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. 2025 Aug 27;1250:155–188. doi: 10.3897/zookeys.1250.145981

On the species status of Blattella germanica and Blattella asahinai (Blattodea, Blattellidae), and other morphologically similar species

Jin-Zhuo Cai 1, Wen-Wen Yao 1, Zong-Qing Wang 1, Yan-Li Che 1,✉
PMCID: PMC12409335  PMID: 40919330

Abstract

Blattella germanica (Linnaeus, 1767), a member of the Blattellidae family within the order Blattodea, is a significant global sanitary pest. Several species within the genus Blattella Caudell, 1903 and its closely related genera (Episymploce Bey-Bienko, 1950; Symploce Hebard, 1916; and Jacobsonina Hebard, 1929) exhibit external morphological traits similar to those of B. germanica. By integrating morphological identification and molecular analyses, one new species was identified: Jacobsonina uncata Cai, Yao & Che, sp. nov. Additionally, Blattella asahinai Mizukubo, 1981 was downgraded to a subspecies of B. germanica. The application of molecular data, specifically cytochrome oxidase c subunit I (COI), has proven to be a straightforward and effective method for distinguishing B. germanica from its morphologically similar relatives.

Key words: ABGD, Blattodea , Blattella germanica asahinai , Jacobsonina , species delimitation, subspecies

Introduction

Due to its rapid reproduction rate, strong adaptability, and effective concealment, Blattella germanica is widely distributed worldwide (Ren et al. 2023). It serves as a vector for various bacteria, viruses, and parasites that can transmit pathogens to humans through contact with contaminated food surfaces, ultimately leading to food poisoning and other health complications (Akinjogunla et al. 2012; Moges et al. 2016; Naqqash et al. 2014). Additionally, allergens present in their molts and excrement can trigger allergic reactions and asthma attacks in sensitive individuals (Gore and Schal 2007; Santos et al. 1999).

Several species within the Blattella genus, such as Blattella asahinai Mizukubo, 1981, Blattella lituricolis (Walker, 1868), and Blattella nipponica Asahina, 1963, as well as species from closely related genera like Jacobsonina aliena (Brunner von Wattenwyl, 1893), exhibit a high degree of morphological similarity to B. germanica. Males of these morphologically similar species are slender, measuring approximately 15.0 mm in body length, and displaying coloration that ranges from pale to dark yellowish brown, with or without markings on the pronotum. They possess well-developed eyes, distinct ocelli, specialized terga, and a supra-anal plate. The significant morphological similarity between B. germanica and its morphologically similar species poses a challenge for accurate differentiation based on subtle variations in male characteristics, such as the pronotum, specialized dorsal glands, and external genitalia (Roth 1985, 1986; Wang et al. 2010), and this may lead to potential errors in population estimates and miscalculations of the amount of control chemicals needed for effective pest management. Therefore, there is an urgent need for a systematic comparison of these subtle variations to clarify the distinguishing characteristics of these morphologically similar species and to develop novel methods for rapidly differentiating B. germanica from its closely related species.

In recent years, COI-based DNA barcoding (658 bp) has emerged as the most widely utilized molecular method for distinguishing cockroach species, demonstrating high precision (Deng et al. 2020; Wang et al. 2021; Han et al. 2022; Li et al. 2023). Favorable results have also been reported for the genera Blattella and Jacobsonina (Yao et al. 2024). Among these species, B. asahinai closely resembles B. germanica morphologically and displays a smaller COI-based genetic distance (0.92%), whereas the genetic divergences between B. germanica and other Blattella species range from 9.44% to 20.25% (Yao et al. 2024). Moreover, B. asahinai is inferred to have diverged from B. germanica approximately 2,100 years ago (Tang et al. 2024). Thus, the taxonomic status of B. germanica and B. asahinai requires clarification through further research. Additionally, the external female genitalia have proven useful in identifying certain cockroach species (Cryptocercus: Bai et al. 2018; Anaplecta: Zhu et al. 2022; Eupolyphaga: Han et al. 2024). However, it remains uncertain whether the external female genitalia can be used to distinguish B. germanica from morphologically similar species.

Consequently, this study integrates morphological and molecular data to accurately distinguish B. germanica from its morphologically similar species. This establishes reliable criteria for their identification and explores the role of female external genitalia in the classification of Blattella species. These findings provide a foundation for the precise identification and evolutionary analysis of the genus Blattella and its close relatives.

Materials and methods

Samples were collected from the southeastern and southwestern regions of China. Specimens were preserved in analytical-grade ethanol and stored at -80 °C until processing. All voucher and type specimens (with details provided in Table 1) examined in this study were deposited at the College of Plant Protection, Southwest University, Chongqing, China (SWU).

Table 1.

Samples used in molecular species delimitation.

Species Location Voucher number GenBank ID
B. bisignata Huizhou, Guangdong BB1 PP730854
Nanning, Guangxi BB2 PP730855
Panzhihua, Sichuan BB3 PP730856
Baoting, Hainan BB4 PP730857
Guigang, Guangxi / KY349784.1
Guangzhou, Guangdong BB5 PP730858
B. germanica laboratory culture BG1 PP730863
Zhongshan, Guangdong / KF640071.1
B. lituricolis Zhongshan, Guangdong / KX962535
Pu’er, Yunnan BL1 PP730864
Yinggeling, Hainan BL2 PP730865
Ganzhou, Jiangxi BL3 PP730866
B. nipponica Chiba, Japan / LC619061
Fuzhou, Fujian BN1 PP730868
Guiyang, Guizhou BN2 PP730869
Hangzhou, Zhejiang BN3 PP730870
Nanjing, Jiangsu BN4 PP730871
Huangshan, Anhui BN5 PP730872
Huanggang, Hubei BN6 PP730873
Qianjiang, Chongqing BN7 PP730874
Meishan, Sichuan BN8 PP730875
Weihai, Shandong BN9 PP730876
Shaoyang, Hunan BN10 PP730877
Chongzuo, Guangxi BN11 PP730878
Huanggang, Hubei BN12 PP730879
B. germanica asahinai State of Florida, United States of America / MG458949
Dehong, Yunnan BA3 PP730853
B. sauteri Putian, Fujian / KY349679
Putian, Fujian BS1 PP730881
Putian, Fujian BS3 PP730883
Bangzhou, Hunan BS2 PP730882
B. radicifera Xishuangbanna, Yunnan / KY349677.1
Xishuangbanna, Yunnan / KY349676.1
Xishuangbanna, Yunnan BR1 PP730880
B. ligulata Xishuangbanna, Yunnan BLI1 PP730867
Dianyuan,Yunnan BlatLigu PV939656
B. foliolata Panzhihua, Sichuan BF1 PP730862
B. biligata Yuxi, Yunnan BBL1 PP730859
Yuxi, Yunnan BBL2 PP730860
B. confusa Yingjiang, Yunnan BC1 PP730861
Tengchong, Yunnan BlatConf PV939657
B. punctoria Xishuangbanna, Yunnan BlatPunc1 PP730894
Xishuangbanna, Yunnan BlatPunc2 PV939658
Xishuangbanna, Yunnan BlatPunc3 PV939659
B. subvittata Sanya, Hainan BlatBisp2 PV939676
Sanya, Hainan BlatBisp1 PV939675
J. aliena Pu’er, Yunnan JA1 PP730884
Qianxinan, Guizhou JA2 PP730885
Pingtangxian, Guizhou JacoAlie OQ736932
J. platysoma Yuxi, Yunnan JP1 PP730886
J. tortuosa Jinghong, Yunnan JT1 PP730887
J. plicata Xishuangbanna, Yunnan JacoPlic1 PP730888
Xishuangbanna, Yunnan JacoPlic2 PP730889
J. subapiculata Yingjiang, Yunnan JacoSuba1 PP730890
Yingjiang, Yunnan JacoSuba2 PP730891
Yingjiang, Yunnan JacoSuba3 PP730892
J. ericonvexa Ruili, Yunnan JacoEric PP730893
J. uncata sp. nov. Xishuangbanna, Yunnan JacoUnca PV939674
E. longiloba Mt. Dawei, Yunnan EpisLong PV939660
E. wulingensis Mt. Limu, Hainan EpisWuli PV939661
Mt. Limu, Hainan EpisWuli2 OQ736929
E. torchaceus Baoting, Hainan EpisTorc1 PV939662
Baoting, Hainan EpisTorc2 PV939663
Maoganxiang, Hainan EpisTorc3 OQ736927
E. brevis Honghe, Yunnan EpisBrev1 PV939664
Qiannan, Guizhou EpisBrev2 PV939665
E. kryzhanovshii Guiyang, Guizhou EpisKryz1 PV939666
Xinping, Yunnan EpisKryz2 PV939667
Xinping, Yunnan EpisKryz3 PV939668
E. spinosa Mt. Dawei, Yunnan EpisSpin PV939669
E. paradoxura Mt. Dawei, Yunnan EpisPara1 PV939670
Mt. Dawei, Yunnan EpisPara2 PV939671
Mt. Dawei, Yunnan EpisPara3 PV939672
S. marginata Mt. Jinyun, Chongqing SympMarg1 PV944124
Mt. Jinyun, Chongqing SympMarg2 PV939673
M. concava / / MF136390
D. punctata / / MF479156
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Morphological terminology used mainly follows Roth (2003) for external morphology, McKittrick (1964) for female external genitalia, Klass (1997) for male external genitalia, and Li et al. (2018) for venation. The abbreviations for female genitalia in this study are as follows: aa.-anterior arch; bsv.-basivalvula; cp.-crosspiece; intc.s.-intercalary sclerite; p.l.-posterior lobes of valvifer II; pp.-paraprocts; pt.-paratergites; SVII-sternum VII; T I–X-abdominal tergites I–X; v.I, II, III- valvules I–III; vlf.I-first valvifer; vlf.Ia-first valvifer arm; vst.s.-vestibular sclerite; and sp.pl.-spermathecal plate. The abbreviations for venation are: CuA-cubitus anterior; CuP-cubitus posterior; M-media; Pcu-postcubitus; R-radius; RA-radius anterior; RP-radius posterior; ScP-subcosta posterior; and V-vannal.

Genital segments of the examined specimens were placed in centrifuge tubes and soaked in 10% NaOH. The tubes were then immersed in hot water (~90 °C) for 15–20 minutes to remove excess fat. Afterward, the genital segments were rinsed with distilled water, and observed in glycerin using a Motic K400 stereomicroscope. Photographs of the specimens and genitalia were captured with a Leica M205A stereomicroscope. All images were edited and assembled into plates using Adobe Photoshop CC 2019.

DNA extraction, PCR, and sequencing were conducted following the methodology outlined by Yao et al. (2024). All 22 newly acquired sequences were submitted to GenBank (https://www.ncbi.nlm.nih.gov/nuccore) with accession numbers PV939656 to PV939676, and PV944124 (Table 1).

A total of 77 COI sequences (658 bp) were analyzed, including 46 sequences from Blattella, 29 from its closely related genera (Episymploce, Symploce and Jacobsonina) (Wang et al. 2023), and two outgroups (Diploptera punctata (Eschscholtz, 1822) and Margattea concava Wang, Che & Wang, 2009). These sequences were aligned using MEGA 11.0 (Kumar et al. 2007) and visually adjusted after translation into amino acid sequences. Genetic divergence values, both intraspecific and interspecific, were quantified using the Kimura 2-parameter (K2P) distance model (Kimura 1980) in MEGA 11.0. The maximum likelihood (ML) tree was constructed in PhyloSuite v. 1.2.3 (Zhang et al. 2020) using IQ-TREE v. 2.1.3 (Nguyen et al. 2014) with models (COI_pos 1, TRN+I+G; COI_pos 2, TIM+I; COI_pos 3, GTR+G) selected by PartitionFinder v. 2.1.1 (Lanfear et al. 2017) based on the corrected Akaike Information Criterion (AICc). Ten independent likelihood searches (each for 10,000 ultrafast bootstrap replicates) were performed, and the result with the highest likelihood was selected. The molecular species delimitation was conducted using the Automatic Barcode Gap Discovery (ABGD) method (Puillandre et al. 2012) on the online platform (https://bioinfo.mnhn.fr/abi/public/abgd/). Default parameters were used, except for the relative gap width, which was set to 1.0, and the Jukes-Cantor (JC69) model was applied.

Results

Morphology

From the general appearance perspective, it is quite challenging to distinguish B. germanica and its morphologically similar species. However, by integrating external morphological traits with genital characteristics – i.e. body size, body coloration, head, male pronotum, specialized abdominal terga, dorsal glands, supra-anal plate, subgenital plate, phallomere, and sclerite structures of female genitalia – we identified a total of 28 morphospecies, which includes one new species, J. uncata Cai, Yao & Che, sp. nov. The identified morphospecies are distributed as follows: Episymploce (7 morphospecies), Symploce (1 morphospecies), Jacobsonina (7 morphospecies), and Blattella (13 morphospecies) among 75 specimens. The results of the morphological comparisons are presented below.

Compared to most species, Blattella ligulata (Bey-Bienko, 1957), Episymploce torchaceus (Feng & Woo, 1999), and Episymploce spinosa (Bey-Bienko, 1969) demonstrate significantly larger body sizes (Figs 1K, 2C, D), while J. aliena and J. uncata sp. nov. are generally smaller (Fig. 2A, B). In terms of body coloration, most species are pale yellowish brown to yellowish brown, while B. ligulata, B. confusa, E. torchaceus, E. spinosa, and Symploce marginata Bey-Bienko, 1927 are overall dark brown (Figs 1J, K, 2C–E).

Figure 1.

Figure 1.

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Male habitus of B. germanica and of its similar species. A. B. germanica; B. B. lituricolis; C. B. asahinai; D. B. nipponica; E. B. bisignata; F. B. sauteri; G. B. radicifera; H. B. punctoria; I. B. biligata; J. B. confusa; K. B. ligulata; L. B. subvittata Scale bars: 5 mm.

Figure 2.

Figure 2.

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Male habitus of B. germanica and of its similar species. A. J. aliena; B. J. uncata sp. nov.; C. E. torchaceus; D. E. spinosa; E. S. marginata. Scale bars: 5 mm.

Most of B. germanica and its similar species are hard to distinguish by characteristics of male head, except for B. confusa, which has a black head (Fig. 3J). In addition, the faces of B. germanica, B. lituricolis, B. asahinai, B. radicifera, Blattella punctoria Yao & Che, 2024, Blattella biligata (Walker, 1868), B. subvittata, and J. aliena are without distinct markings (Fig. 3A–C, G–I, L, N), while other species have distinct markings (Fig. 3D–F, K, O–Q).

Figure 3.

Figure 3.

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Head of B. germanica and of its similar species. A. B. germanica; B. B. lituricolis; C. B. asahinai; D. B. nipponica; E. B. bisignata; F. B. sauteri; G. B. radicifera; H. B. punctoria; I. B. biligata; J. B. confusa; K. B. ligulata; L. B. subvittata; M. J. aliena; N. J. uncata sp. nov.; O. E. torchaceus; P. E. spinosa; Q. S. marginata. Scale bars: 1 mm.

Markings of male pronotum are similar in B. germanica, B. lituricolis, B. asahinai, B. bisignata, and B. nipponica, all with two black longitudinal strips (Fig. 4A–E). The pronotum of B. sauteri, B. radicifera, B. punctoria, B. ligulata, E. torchaceus, E. spinosa, and S. marginata also have distinct markings (Fig. 4F–H, K, O–Q). the pronotum of B. confusa has two large black markings and a thin white marking in the middle part, which is easily recognizable (Fig. 4J) while the pronota of B. biligata and J. aliena lack distinct markings (Fig. 4I, M).

Figure 4.

Figure 4.

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Male pronotum of B. germanica and of its similar species. A. B. germanica; B. B. lituricolis; C. B. asahinai; D. B. nipponica; E. B. bisignata; F. B. sauteri; G. B. radicifera; H. B. punctoria; I. B. biligata; J. B. confusa; K. B. ligulata; L. B. subvittata; M. J. aliena; N. J. uncata sp. nov.; O. E. torchaceus; P. E. spinosa; Q. S. marginata. Scale bars: 1 mm.

The abdominal tergites, TVII and TVIII are specialized in B. germanica, B. lituricolis, B. asahinai, B. bisignata and B. nipponica. TI and TVII are specialized in S. marginata. B. sauteri, B. punctoria, B. radicifera, B. biligata, B. confusa, B. ligulata, B. subvittata, and E. torchaceus all have only one specialized abdominal tergite, TVIII. Specialization of TI, VII, and IX occurs in E. spinosa. All species of Jacobsonina lack specialized abdominal tergites. TVII of B. germanica, B. lituricolis, and B. asahinai has two transverse grooves near the anterior margin of the middle area (Fig. 5A–C, Table 2). TVII of B. germanica and B. lituricolis have two transverse grooves on the posterior margin of the median of TVII, but the grooves of B. lituricolis are narrower. B. asahinai lacks grooves on the posterior margin of TVII. A pair of open grooves is present in the anterior margin of the median domain of TVII in B. bisignata and B. nipponica. In addition, B. bisignata has a narrow groove in the posterior margin of TVII, but B. nipponica does not (Fig. 5D, E, Table 2). The groove on TVII of B. bisignata is not covered by TVI and was obviously exposed, the groove on TVII of B. nipponica is not significantly exposed (Fig. 6D, E, Table 2).

Figure 5.

Figure 5.

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Abdominal tergite 7 of B. germanica and of its similar species. A. B. germanica; B. B. lituricolis; C. B. asahinai; D. B. nipponica; E. B. bisignata; F. B. sauteri; G. B. radicifera; H. B. punctoria; I. B. biligata; J. B. confusa; K. B. ligulata; L. B. subvittata; M. E. spinosa; N. S. marginata; O. E. torchaceus; P. J. aliena. Scale bars: 0.5 mm.

Table 2.

Comparison of important distinguishing features of B. germanica and its morphologically similar relatives.

Species Abdominal tergite 7 Glandular fossae of abdominal tergite 8 Abdominal tergite 1 Abdominal tergite 9 Supra-anal plate Subgenital plate
B. germanica two transverse grooves near the anterior margin of the middle area exposed and broad, the posterior margin setose / / left and right paraprocts broad and similar, both bifurcated with a flat apical part and a subrectangular notch at the left corner
B. lituricolis the grooves narrower distinct, glandular openings not attached / / left and right paraprocts broad and similar, both bifurcated with a flat apical part and a subrectangular notch at the left corner
B. asahinai no grooves on the posterior margin partially obscured by tergite 7 and only two upward-elevated hairy margins visible / / left and right paraprocts broad and similar, both bifurcated with a flat apical part and a subrectangular notch at the left corner
B. nipponica the groove not significantly exposed inconspicuously exposed / / left and right paraprocts broad and similar, both bifurcated with a flat apical part and a subrectangular notch at the left corner
B. bisignata the groove not covered by tergite 6 and obviously exposed obviously exposed / / left and right paraprocts broad and similar, both bifurcated with a flat apical part and a subrectangular notch at the left corner
B. sauteri the triangular region of posterior margin with setae / / / the base of the right paraproct expanded and tapered toward the end with small spines on the middle of both sides
B. radicifera the posterior margin of the ridge with a densely setose area / / / right paraproct with a trifurcate protrusion with small spines on the middle of both sides
B. punctoria the triangular region of posterior margin with setae / / / with a small spine at each posterior lateral corner with a small spine on the left side
B. biligata a small area between the two fossae bearing dense setae / / / with a broad and rounded posterior margin no spines on either margin
B. confusa a central ridge and a deep rounded fossa on each side of the ridge / / / right paraproct tapers to a point with a small protuberance between the styli
B. ligulata a triangular and setose area with two large fossae on either side / / / right paraproct slender, arched and curved outer margin of the left stylus spiny
B. subvittata two distinct fossae and a setose area / / / the middle part of the posterior margin bearing two spines protuberance in the middle lateral margins long
J. aliena unspecialized / / / right paraproct pincer-like lower margin truncate
J. uncata sp. nov. unspecialized / / / left posterior lateral corner bearing three spinules and right bearing two spinules left hind lateral corner bearing many spinules
E. torchaceus sparsely covered with setae / / / left margin bearing three spinules and right margin bearing four spinules left stylus folded from center to the upper left
E. spinosa an obscure protrusion with a small dimple on both sides / specialized with the middle part bearing tufted setae with a serrated and slightly curved margin left posterior margin bearing two spine-like protrusions left margin arched and outer margin densely covered with small spines
S. marginata two fossae with small setae / specialized with the middle part bearing tufted setae / with a small protrusion on its left lateral margin left stylus points from left towards right with the apical part sharp
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Figure 6.

Figure 6.

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Dorsal glands of B. germanica and of its similar species. A. B. germanica; B. B. lituricolis; C. B. asahinai; D. B. bisignata; E. Blattella confusa; F. B. sauteri; G. B. radicifera; H. B. punctoria; I. B. biligata; J. B. nipponica; K. B. ligulata; L. S. marginata; M. E. spinosa; N. E. torchaceus. Scale bars: 0.5 mm.

There is no obvious difference between the TVII of B. sauteri and B. punctoria. The anterior margin of the median domain of TVII has an upwardly protruding ridge, the triangular region of posterior margin has setae, and a rounded socket is present on each side (right and left), which is covered by TVI when not dissected (Fig. 6F, H, Table 2). The remaining species have clearly differentiated characteristics of TVII, making it easy to distinguish. That of B. radicifera has a sub-trapezoidal elevated ridge in the middle part, the posterior margin of the ridge has a densely setose area, and a rounded fovea is present on each side of the ridge (Fig. 5G, Table 2). TVII of B. biligata is distinctly broad, with the anterior half having a pair of deep fossae, a longitudinal ridge between the two fossae, and a small area between the two fossae bearing dense setae (Fig. 6I, Table 2). TVII of B. confusa is distinctly broad, with a central ridge and a deeper rounded fossa on each side of the ridge (Fig. 5J, Table 2). The middle part of TVII of B. ligulata has a triangular and setose area, with two large fossae on either side (Fig. 5K, Table 2). TVII of B. subvittata has two distinct fossae and a setose area (Fig. 5L, Table 2). The middle part of TVII of E. spinosa has an obscure protrusion, with a small dimple on both sides (Figs 5M, 6M, Table 2). TVII of S. marginata has two fossae, and the anterior margin of the fossae has small setae (Figs 5N, 6L, Table 2). The middle part of TVII of E. torchaceus is sparsely covered with setae (Figs 5O, 6N, Table 2). Jacobsonina aliena does not have a specialized abdominal TVII (Fig. 5P, Table 2).

Morphological differences of TVIII among B. germanica, B. lituricolis, B. asahinai, B. bisignata, and B. nipponica are pronounced. The median longitudinal groove of tergite 8 in B. germanica is conspicuous, dorsal glandular fossae exposed, broad, and suborbicular or ellipsoid. The glandular openings are connected or nearly connected at the anterior margin, and the posterior margin is setose (Fig. 7A, Table 2). The glandular fossa in TVIII of B. lituricolis is covered by TVII near the anterior margin (Fig. 6B, Table 2). The glandular fossa is distinct, with glandular openings not attached; the inner margin extends toward the center, and the basal extension is thicker than the terminal one (Fig. 7B, Table 2). Glandular fossae in TVIII of B. asahinai are partially obscured by TVII, only with two upward-elevated hairy margins visible (Fig. 6C, Table 2). Two dorsal glandular fossae are oblate, their anterior margins nearly connected, posterior margins medially setose, unconnected, and slightly upwardly curved (Fig. 7C, Table 2).

Figure 7.

Figure 7.

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Abdominal tergites 1, 8 and 9 of B. germanica and of its similar species. A. B. germanica; B. B. lituricolis; C. B. asahinai; D. B. nipponica; E. B. bisignata; F. S. marginata; G. E. spinosa; H. E. spinosa. Scale bars: 0.5 mm.

When not dissected, the glandular fossa in TVIII of B. bisignata is obviously exposed (Fig. 6D, Table 2), whereas that of B. nipponica is inconspicuously exposed (Fig. 6E, Table 2). TVIII of B. bisignata and B. nipponica has a longitudinal ridge in the middle, two flaky glandular fossae, a nearly connected anterior margin of the fossae, and posterior margins that are not closed and slightly retracted toward the middle ridge (Fig. 7D, E, Table 2).

TI of S. marginata and E. spinosa is specialized, with the middle part bearing tufted setae (Fig. 7F, G, Table 2). The ventral margin of the right dorsal lobe of TIX in E. spinosa extends backward, with a serrated and slightly curved margin (Fig. 7H, Table 2).

The supra-anal plates of B. germanica, B. lituricolis, B. asahinai, B. nipponica, and B. bisignata are similar in morphology: distinctly longer than the subgenital plates overall; left and right paraprocts broad and similar, both being bifurcated (Fig. 8A–E, Table 2). The posterior margin of supra-anal plate of B. sauteri is concave inward at the middle part; the apex of the left paraproct is bifurcated, and the base of the right paraproct is expanded and tapered toward the end (Fig. 8F, Table 2). The posterior margin of supra-anal plate of B. radicifera is concave inward at the middle part, with a small spinule at each posterior lateral angle. The left paraproct has a bifurcate protrusion, and the right paraproct has a trifurcate protrusion (Fig. 8G, Table 2).

Figure 8.

Figure 8.

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Supra-anal plate of B. germanica and of its similar species. A. B. germanica; B. B. lituricolis; C. B. asahinai; D. B. nipponica; E. B. bisignata; F. B. sauteri; G. B. radicifera; H. B. punctoria; I. B. biligata; J. B. confusa; K. B. ligulata; L. B. subvittata; M. J. aliena; N. J. uncata sp. nov.; O. E. torchaceus; P. E. spinosa; Q. S. marginata. Scale bars: 1 mm.

The supra-anal plate of B. punctoria has a small spine at each posterior lateral corner; both paraprocts are bifurcate. The left paraproct bears multiple small spines at basal part, and the right paraproct has two small spines in middle of both branches (Fig. 8H, Table 2). The supra-anal plate of B. biligata is symmetrical, with a broad and rounded posterior margin. Both paraprocts are pointed at apex, with the left paraproct positioned above and the right paraproct below (Fig. 8I, Table 2). The supra-anal plate of B. confusa is ligulate, with the posterior margin slightly smooth in middle part. The left paraproct gradually expands from the base toward the tip, and the right paraproct gradually tapers to a point (Fig. 8J, Table 2). The supra-anal plate of B. ligulata is ligulate. The left paraproct is broad at basal part, with apical part bearing four small bifurcations. The right paraproct is slender, arched (Fig. 8K, Table 2). The supra-anal plate of B. subvittata is nearly symmetrical, with the middle part containing a hyaline area and the middle part of the posterior margin bearing two spines. The left paraproct has a terminal curved hook-like protrusion and a tapering protrusion; the right paraproct has a protrusion slightly twisted at the apex (Fig. 8L, Table 2). The supra-anal plate of J. aliena is symmetrical, with a smooth posterior margin. The left paraproct is finger-like, with the lower margin densely covered with small spines; the right paraproct is pincer-like (Fig. 8M, Table 2). The supra-anal plate of J. uncata sp. nov. is unsymmetrical, with the left posterior lateral corner bearing three spinules and the right bearing two spinules. The left paraproct is simple, with the apical part bearing four spinules and the basal part having one curved and short fork (the fork’s apex with 5 spinules). The right paraproct is complex: the apical part without spinules, one of its two forks is robust with a strongly curved hooked end, and the other fork is long and bent towards the right (Fig. 8N, Table 2). The supra-anal plate of E. torchaceus is symmetrical and subtrapezoidal, with the middle of posterior margin slightly concave inwards, the left margin bearing three spinules, and the right margin bearing four spinules. The left paraproct is bifurcated, with one long and one short bifurcation. The right paraproct has a rounded area bearing spinules and a trifurcated protrusion (Fig. 8O, Table 2). The supra-anal plate of E. spinosa is asymmetrical, with the left posterior margin bearing two spine-like protrusions (1 straight, the other curved upwards). The left paraproct has two small forks, the right paraproct has one small protrusion (Fig. 8P, Table 2). The posterior margin of supra-anal plate of S. marginata is slightly concave inwards medially. The apical part of the left paraproct is bifurcated: one surface bears spinules, and the other has an acutely protruding apex. The supra-anal plate exhibits a small protrusion on its left lateral margin (Fig. 8Q, Table 2).

The subgenital plates of B. germanica, B. lituricolis, B. asahinai, B. nipponica, and B. bisignata are similar: featuring a flat apical part and a subrectangular notch at the left corner (Fig. 9A–E, Table 2). The left stylus is situated at the end of the notch, with the apex bearing several small spinules. The right stylus is small, rounded, and is positioned very close to the left stylus.

Figure 9.

Figure 9.

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Subgenital plate of B. germanica and of its similar species. A. B. germanica; B. B. lituricolis; C. B. asahinai; D. B. nipponica; E. B. bisignata; F. B. sauteri; G. B. radicifera; H. B. punctoria; I. B. biligata; J. B. confusa; K. B. ligulata; L. B. subvittata; M. J. aliena; N. J. uncata sp. nov.; O. E. torchaceus; P. E. spinosa; Q. S. marginata. Scale bars: 1 mm.

The subgenital plates of B. sauteri, B. radicifera, B. punctoria and B. biligata are similar and asymmetrical, with posterior margins protruding medially and two finger-like styli (Fig. 9F–I, Table 2). Both B. sauteri and B. radicifera bear small spines on the middle of both sides of the subgenital plate, but B. radicifera is broader overall than B. sauteri. The right stylus is located on the right side of the posterior margin in B. sauteri, while in B. radicifera, it is located at the middle of the posterior margin (Fig. 9F, G, Table 2). The subgenital plate of B. biligata lacks spines on either margin. B. punctoria bears a small spine on the left side only, with the notch in the left posterior lateral corner being more pronounced (Fig. 9H, I, Table 2).

The subgenital plates of B. confusa, B. ligulata, and B. subvittata are readily distinguishable. The two styli of B. confusa are long, with the basal part expanded, the apical part pointed, and a small protuberance between the styli (Fig. 9J, Table 2). The outer margin of the left stylus of B. ligulata is spiny (Fig. 9K, Table 2). The protuberance in the middle lateral margins of B. subvittata is long (Fig. 9L, Table 2).

The subgenital plate of J. aliena is asymmetrical, with the posterior margin medially protruded and the lower margin truncate. Margins bear some small spines. Styli absent (Fig. 9M, Table 2). The subgenital plate of J. uncata sp. nov. is asymmetrical, with the left side thickened and the left hind lateral corner bearing many spinules. Styli absent (Fig. 9N, Table 2). The subgenital plate of E. torchaceus is asymmetrical, with the posterior margin slightly protruded medially, the right margin rounded, and the left margin slightly concave internally in the terminal half. Two styli are inserted at the middle of the posterior margin. The left stylus is folded from center to the upper left, with small spines at the folded corners. The right stylus is smaller and bears three small spines (Fig. 9O, Table 2).

The subgenital plate of E. spinosa is asymmetrical, with the left margin arched, the outer margin densely covered with small spines, and the apical extension acuminate. The spiny tip of the right extension is distinctly smaller than left. The left stylus is long; The right stylus is short (Fig. 9P, Table 2). The subgenital plate of S. marginata is asymmetrical, with the posterior margin bearing two projections: one longer, projecting from the right side towards the left, and the other stout, short and projecting downwards. The left stylus points from the left towards the right, with the apical part sharp; the right stylus extends vertically downwards (Fig. 9Q, Table 2).

The morphology of the left phallomere is similar in most B. germanica and its morphologically similar species, but there are some exceptions. The left phallomere of B. germanica, B. lituricolis, B. asahinai, B. nipponica, and B. bisignata is similar, while the inner edge of the curved hook of B. lituricolis is dentate and the others are smooth (Fig. 10A–E). The curved hook portion of the left phallomere of B. ligulata is short, broad, and twisted with a sharp apex (Fig. 10K). The left phallomere of J. aliena has a banded and hairy accessory sclerite (Fig. 10M). The left phallomere of J. uncata sp. nov. bears two bristly accessory sclerites (Fig. 10N). The left phallomere of E. torchaceus is unusually robust except for the curved hook-like portion (Fig. 10O). The accessory sclerite of S. marginata is lamellar, broad (Fig. 10Q). The morphology of the middle phallomere is similar in most B. germanica and its morphologically similar species, all possessing an elongate, poorly sclerotized basal part and an acute, strongly sclerotized apical part. The apical part of the middle phallomere of B. punctoria has a bifurcation (Fig. 11H); the apical part of B. subvittata bears an elongate bony sclerite (Fig. 11L); and the middle part of S. marginata is wide (Fig. 11Q). The right phallomere of B. germanica and its morphologically similar species has an inverted Y-shaped elongate sclerite and a curved lamellate sclerite. In addition, the right phallomere of many species also has other sclerites. Blattella sauteri has a spiny, irregular sclerite on the surface (Fig. 12F); B. radicifera has an oval sclerite bearing some spines at the lateral margins, with a basal expanded protrusion attached to the left side (Fig. 12G); B. punctoria has an oval sclerite bearing three long spines at the basal part, to which also attached a lamellate, bristly-margined sclerite (Fig. 12H); B. biligata has a lamellar and spiny sclerite (Fig. 12I); B. confusa has a bifurcated sclerite (Fig. 12J); B. ligulata has a large, spiky-ended sclerite (Fig. 12K); B. subvittata has a sclerite with ten small spines on the margin and a short protruding, the apex of which with four spines (Fig. 12L). Jacobsonina aliena has a thin, flaky, poorly sclerotized sclerite (Fig. 12M). Episymploce torchaceus has a broad sclerite with five small spines on the right middle part (Fig. 12O); E. spinosa has a bifurcate sclerite and an ovoid and lamellar sclerite (Fig. 12P). Symploce marginata has a sclerite bearing small spines on posterior margin (Fig. 12Q).

Figure 10.

Figure 10.

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Left phallomere of B. germanica and of its similar species. A. B. germanica; B. B. lituricolis; C. B. asahinai; D. B. nipponica; E. B. bisignata; F. B. sauteri; G. B. radicifera; H. B. punctoria; I. B. biligata; J. B. confusa; K. B. ligulata; L. B. subvittata; M. J. aliena; N. J. uncata sp. nov.; O. E. torchaceus; P. E. spinosa; Q. S. marginata. Scale bars: 1 mm.

Figure 11.

Figure 11.

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Middle phallomere of B. germanica and of its similar species. A. B. germanica; B. B. lituricolis; C. B. asahinai; D. B. nipponica; E. B. bisignata; F. B. sauteri; G. B. radicifera; H. B. punctoria; I. B. biligata; J. B. confusa; K. B. ligulata; L. B. subvittata; M. J. aliena; N. J. uncata sp. nov.; O. E. torchaceus; P. E. spinosa; Q. S. marginata. Scale bars: 1 mm.

Figure 12.

Figure 12.

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Right phallomere of B. germanica and of its similar species. A. B. germanica; B. B. lituricolis; C. B. asahinai; D. B. nipponica; E. B. bisignata; F. B. sauteri; G. B. radicifera; H. B. punctoria; I. B. biligata; J. B. confusa; K. B. ligulata; L. B. subvittata; M. J. aliena; N. J. uncata sp. nov.; O. E. torchaceus; P. E. spinosa; Q. S. marginata. Scale bars: 1 mm.

The structure of the female external genitalia of Blattella species is broadly similar (Fig. 13). The posterior margin of supra-anal plate prominent. Paraprocts are broadly lamellar. Paratergites are banded. Intercalary sclerite are symmetrical, lamellar, mostly subtriangular, and slightly rounded in a few cases. Valves are not well sclerotized, short. Crosspieces are distinct, with a slender basal part and an oval or irregular shaped apical part. Posterior lobes of valvifer II are sub-rectangular. First valvifer arm are nearly symmetrical, almost U-shaped, relatively flat, and with a spiny or smooth surface. Basivalvula are lamellar and slightly broad, with a surface that may or may not bear spines. Laterosternal shelf are well sclerotized or not, irregular shaped. Vestibular sclerite are well sclerotized and either lamellar or long-banded. Among these species, the main sclerite structures in which differences exist are the following: the intc.s. of B. germanica and B. bisignata are nearly right triangles (Fig. 14A, D); those of B. lituricolis, B. asahinai, and B. nipponica are fan-shaped (Fig. 14B, C, E); intc.s. of B. radicifera and B. punctoria are similar with rounded edges and an overall approximate trapezoid shape (Fig. 14G, H); and the intc.s. of B. ligulata is nearly heart-shaped (Fig. 14I). The middle part of the outer margins of the pp. of B. germanica, B. lituricolis, B. asahinai, B. bisignata, B. nipponica, and B. ligulata is concave inwardly (Fig. 15A–E, I); B. germanica and B. nipponica both with a sharp apex (Fig. 15A, E), while B. lituricolis, B. asahinai, B. bisignata, and B. ligulata have a more rounded apex (Fig. 15D, I). The pp. of B. sauteri is the most recognizable, with its posterior margins sharp and converging toward the middle (Fig. 15F) while the pp. of B. radicifera and B. punctoria are similar (Fig. 15G, H).

Figure 13.

Figure 13.

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Female external genitalia of B. germanica and of its similar species. A. B. germanica; B. B. lituricolis; C. B. asahinai; D. B. bisignata; E. B. nipponica; F. B. sauteri; G. B. radicifera; H. B. punctoria; I. B. ligulata. Scale bars: 1 mm. Abbreviations: aa.-anterior arch; bsv.-basivalvula; cp.-crosspiece; intc.s.-intercalary sclerite; p.l.-posterior lobes of valvifer II; pp.-paraprocts; pt.-paratergites; SVII-sternum VII; T I–X-abdominal tergites I–X; v.I, II, III- valvules I–III; vlf.I-first valvifer; vlf.Ia-first valvifer arm; vst.s.-vestibular sclerite; and sp.pl.-spermathecal plate.

Figure 14.

Figure 14.

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The intc.s. of B. germanica and of its similar species. A. B. germanica; B. B. lituricolis; C. B. asahinai; D. B. bisignata; E. B. nipponica; F. B. sauteri; G. B. radicifera; H. B. punctoria; I. B. ligulata. Scale bars: 0.5 mm.

Figure 15.

Figure 15.

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The pp. of B. germanica and of its similar species. A. B. germanica; B. B. lituricolis; C. B. asahinai; D. B. bisignata; E. B. nipponica; F. B. sauteri; G. B. radicifera; H. B. punctoria; I. B. ligulata. Scale bars: 0.5 mm.

The vlf.Ia of B. germanica, B. lituricolis, B. asahinai, B. bisignata, and B. nipponica is not setose (Fig. 16A–E), but that of B. sauteri, B. radicifera, B. punctoria, and B. ligulata is setose (Fig. 16F–I). The setae are evenly distributed on the surface of vlf.Ia in B. sauteri (Fig. 16F), but are only distributed on the edges of the vlf.Ia in B. radicifera, B. punctoria, and B. ligulata (Fig. 16G–I).

Figure 16.

Figure 16.

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The vlf.Ia of B. germanica and of its similar species. A. B. germanica; B. B. lituricolis; C. B. asahinai; D. B. bisignata; E. B. nipponica; F. B. sauteri; G. B. radicifera; H. B. punctoria; I. B. ligulata. Scale bars: 0.5 mm.

Molecular analysis based on COI sequences

The maximum likelihood (ML) tree constructed from COI sequences demonstrated that samples identified as the same morphospecies based on morphological traits were clearly grouped together. Additionally, most terminal branches exhibited relatively strong support values (Fig. 17). The ABGD analysis categorized 75 ingroup COI sequences into 27 molecular operational taxonomic units (MOTUs), which closely aligned with the results of the morphological delimitation. The only discrepancy was the relationship between B. germanica and B. asahinai.

Figure 17.

Figure 17.

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Maximum likelihood (ML) tree based on COI sequences. Branch labels represent bootstrap support percentages. Colored bars indicate species delimitation results obtained through different methods. A. Morphology (blue); B. ABGD results (purple).

The morphological similarities between B. germanica and B. asahinai are evident in several aspects: body coloration yellowish brown (Fig. 18A, B, K, L), interocular space approximately equal to the distance between ocelli (Fig. 18C, M), male pronotum with two black longitudinal strips (Fig. 18G, Q), the male abdominal tergites 7 and 8 specialized (Fig. 18D, H, N, R), left and right paraprocts of supra-anal plate bifurcated (Fig. 18F, P), and subgenital plates with a sub-rectangular notch at the left corner (Fig. 18J, T). The sclerite structures of female external genitalia also show striking resemblances, including TX, pp., pt., intc.s., cp., p.l., vlf.Ia, bsv., and ltst.sh (Fig. 18U, V). Despite these similarities, several differences were observed: (1) the male abdominal tergite 8: the posterior margin of the glandular fossae in B. asahinai not curved forward and not extending beyond the anterior margin, in contrast to B. germanica (Fig. 18H, R) (Roth 1986); (2) the first ootheca (refers to the first ootheca cockroach produced, the original author’s meaning) and first instars of B. asahinai smaller than those of B. germanica; with colorless (white) spots present at the margins and central region of abdominal tergite in late instars of B. asahinai, whereas these spots on B. germanica are lightly pigmented (n = 10 specimens per species; Ross and Mullins 1988); (3) additionally, B. germanica primarily inhabits indoor environments (Tang et al. 2019), while B. asahinai predominantly lives outdoors (Richard et al. 1988). In this study, specimens of B. germanica used for morphological observations and COI sequencing were laboratory-reared, while specimens of B. asahinai were collected from wild forest habitats in Yunnan Province. Given the limited length (658 bp) of the COI sequences and the nearly exclusive Chinese origin of the samples, we recommend expanding genetic sampling across broader geographical ranges and incorporating morphological analyses, supplemented by whole-genome sequencing approaches, to clarify the relationship between B. germanica and B. asahinai. Despite these limitations, the extremely low genetic distance (0.92%) between B. germanica and B. asahinai, coupled with their high morphological congruence, distinct ecological niches, and successful laboratory hybridization yielding viable F1 and F2 generations (Roth 1986), strongly support reclassifying B. asahinai as a subspecies of B. germanica (see Taxonomy section).

Figure 18.

Figure 18.

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Comparative morphology of B. germanica and B. asahinai. A–J, U. B. germanica; K–T, V. B. asahinai. A. Habitus, dorsal view; B. Habitus, ventral view; C. Head, ventral view; D. Abdominal tergite 7, ventral view; E. Dorsal glands, dorsal view; F. Supra-anal plate, ventral view; G. Pronotum, dorsal view; H. Abdominal tergite 8, ventral view; I. Phallomere; J. Subgenital plate, ventral view; K. Habitus, dorsal view; L. Habitus, ventral view; M. Head, ventral view; N. Abdominal tergite 7, ventral view; O. Dorsal glands, dorsal view; P. Supra-anal plate, ventral view; Q. Pronotum, dorsal view; R. Abdominal tergite 8, ventral view; S. Phallomere; T. Subgenital plate, ventral view; U, V. Female external genitalia. Scale bars: 5 mm (A, B, K, L); 1 mm (C, F, G, I, J, M, P, Q, S–V); 0.5 mm (D, E, H, N, O, R). Abbreviations: aa.-anterior arch; bsv.-basivalvula; cp.-crosspiece; intc.s.-intercalary sclerite; p.l.-posterior lobes of valvifer II; pp.-paraprocts; pt.-paratergites; SVII-sternum VII; T I–X-abdominal tergites I–X; v.I, II, III- valvules I–III; vlf.I-first valvifer; vlf.Ia-first valvifer arm; vst.s.-vestibular sclerite; and sp.pl.-spermathecal plate.

Based on the combined results of molecular analysis and morphological data, we successfully classified morphologically similar samples into 28 species (including one potential subspecies). The ABGD results corroborated the morphological delimitations, demonstrating that molecular data (COI) are effective for distinguishing B. germanica from its morphologically similar species. The intra- and interspecific genetic distances of 75 ingroup sequence are provided in Suppl. material 1. The interspecific genetic distances observed in this study ranged from 5.61% (between B. nipponica Asahina, 1963 and B. bisignata (Brunner von Wattenwyl, 1893) and between E. paradoxura Bey-Bienko, 1950 and E. spinosa (Bey-Bienko, 1969)) to 23.27% (between B. radicifera (Hanitsch, 1928) and B. confusa Princis, 1950). For B. germanica, the smallest genetic distance was 9.44% (to B. bisignata), while the largest was 20.81% (to E. brevis Qiao & Che, 2022).

Taxonomy

. Jacobsonina uncata

Cai, Yao & Che sp. nov.

FF93F04E-68B3-5F38-9C0C-871FBA1E5520

https://zoobank.org/6C27ABAD-966B-4DD9-83EB-12E1F878DD8E

Fig. 19A–J

Figure 19.

Figure 19.

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Holotype of Jacobsonina uncata Cai, Yao & Che, sp. nov. A. Habitus, dorsal view; B. Habitus, ventral view; C. Pronotum, dorsal view; D. Head, ventral view; E. Supra-anal plate, ventral view; F. Front femur, ventral view; G. Subgenital plate, ventral view; H. Left phallomere, ventral view; I. Median phallomere, ventral view; J. Right phallomere, ventral view. Scale bars: 5 mm (A, B); 1 mm (C–J).

Type material.

Holotype: China • male; Yunnan Province, Xishuangbanna City, Jinuo Township, Situ Xinzhai; 13 July 2020; Li-Kang Niu, Yi-Shu Wang leg. Paratypes: China • 1 male & 1 female, same collection data as holotype.

Measurements

(mm). Male, overall length (including tegmen): 11.2, tegmina length: 8.8, pronotum length × width: 2.3 × 2.5.

Diagnosis.

The principal morphological distinction between J. uncata sp. nov. and congeneric species resides in the medial region of posterior margin of the supra-anal plate: Jacobsonina species generally exhibit either a slight concavity or rounded convexity, whereas J. uncata sp. nov. displays a pronounced concave configuration. This species resembles Jacobsonina tortuosa Wang, Jiang & Che, 2009 in body size and coloration, but can be distinguished by the following characteristics: 1) J. uncata sp. nov. with spines on the posterior lateral corner of the supra-anal plate (absent in J. tortuosa); 2) the hook phallomere of J. uncata sp. nov. with two hairy accessory sclerites, whereas only one accessory sclerite in J. tortuosa; 3) the conspicuous curved hook structure on the posterior margin of right paraproct in J. uncata sp. nov. (absent in J. tortuosa).

Description.

Male. Coloration. Body yellowish. (Fig. 19A, B). Head and face yellowish brown. Pronotum yellowish brown, without distinct markings. Ocelli pink. Basal part of antennae yellowish brown. Maxillary palpi dark brown (Fig. 19C, D). Abdomen pale brown. Legs yellowish brown (Fig. 19F).

Head. Interocular space about same as the distance between antennal sockets, slightly narrower than the distance between ocelli. Pronotum. Anterior margin slightly convex, lateral margins rounded, posterior margin slightly protruded medially (Fig. 19C). Tegmina and wings. Both fully developed, extending beyond the end of abdomen. Legs. Anteroventral margin of front femur Type B3 (Fig. 19F). Pulvilli present. Tarsal claws symmetrical and unspecialized, with arolia present. Abdomen and genitalia. Abdominal tergum unspecialized. Supra-anal plate unsymmetrical, left posterior lateral corner with two spines, the right with three spines. Paraprocts dissimilar. Left paraproct specialized, with apical part and distal part both hooked; the former comparatively short, strongly bent with the apex smooth and directed to the right; the latter strongly elongated and curved to the left, four spines present near the apex. Right paraproct simple, apical part with four stout spines; basal part with the hooked projection slightly curved, inner margin with four spines present (Fig. 19E). Subgenital plate unsymmetrical with left side thickened, left posterior lateral corner with several spines; styli absent (Fig. 19G). The terminal incision of the hook phallomere distinct, two accessory sclerites with long hairs (Fig. 19H). Median phallomere slender, the basal part widened at base and sharply narrowed at apex (Fig. 19I). Right phallomere complex: anterior sclerite weakly sclerotized and expanded basally; middle sclerite well sclerotized, posterior sclerite with small projection (Fig. 19J).

Etymology.

The specific epithet originates from the Latin term uncatus, which refers to the conspicuous curved hook structure on the posterior margin of right paraproct.

Distribution.

China (Yunnan).

. Blattella subvittata

Hebard, 1929

2ABA7987-DCD2-5BCF-AE62-964DFF5C0CC4

Fig. 20A–O

Figure 20.

Figure 20.

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Blattella subvittata Hebard A, B, E–O. Male; C, D. Female. A. Habitus, dorsal view; B. Habitus, ventral view; C. Habitus, dorsal view; D. Habitus, ventral view; E. Pronotum, dorsal view; F. Head, ventral view; G. Tegmen, ventral view; H. Hind wing, ventral view; I. Abdominal tergite 7, ventral view; J. Front femur, ventral view; K. Median phallomere, ventral view; L. Supra-anal plate, ventral view; M. Left phallomere, ventral view; N. Right phallomere, ventral view; O. Subgenital plate, ventral view. Scale bars: 5 mm (A, B, C, D, G, H); 1 mm (E, F, I–O).

Type locality.

“Pasoeroean, eastern Java”.

New material examined.

China • 1 male & 1 female; Hainan Province, Sanya City, Jiyang Town, Liupan Cun; 8 Apr. 2015; Xin-Ran Li, Zhi-Wei Qiu leg. • 1 female; Guangdong Province, Gaozhou City, Genzi Town; 11 June 2019; Rong Chen, Shan Gao leg. • 2 males; Hainan Province, Yinggeling, Nankai protection station; 14 July 2023; Yi-Shu Wang, Jin-Zhuo Cai leg. • 1 female; Hainan Province, Jianfeng Town; 18 July 2023; Yi-Shu Wang, Jin-Zhuo Cai leg.

Distribution.

China (Guangdong, Hainan, Taiwan); Indonesia, Philippines, Malaysia, Thailand.

Remark.

Based on the markings of pronotum, the shape of abdominal tergite 7, and the structure of subgenital plate and supra-anal plate, samples from Hainan and Guangdong were identified as B. subvittata, with the closest genetic distance to B. punctoria (12.32%).

. Blattella germanica asahinai

(Mizukubo, 1981) stat. nov.

0FFEADDB-1596-58BA-ACB7-8ADD0E0AAD93

  • Blattella asahinai Mizukubo, 1981: 153; Roth 2003: 87.

  • Blattella beybienkoi Roth, 1985: 28. Synonymized by Roth 1986: 371.

Material examined.

China • 3 females; Yunnan Province, Baoshan City, Baihualing, Jiu Jiezi; 24 Aug. 2015; Xin-Ran Li, Zhi-Wei Qiu leg. • 1 male; Yunnan Province, Dehong Dai and Jingpo Autonomous Prefecture, Yingjiang County, Nabang Town; 11 July 2012; Dong Wang leg.

Remarks.

Based on morphological comparisons, the genetic distance, and the ABGD delineation results, B. asahinai is considered to be a subspecies of B. germanica. The primary distinctions between B. germanica and B. asahinai are primarily observed in the morphology of the glandular fossae present on the eighth abdominal tergite, the varying sizes of their first ootheca, the coloration of the abdominal tergite during the later instars, and their distinct habitat environments (see Results and Fig. 18 for further details).

Distribution.

China (Taiwan, Yunnan); England, India, Indonesia, Japan, Malaysia, Myanmar, Thailand, United States.

Conclusions

Our results indicate that the ABGD methodology generates species hypotheses for B. germanica and its morphologically similar species that are highly consistent with those derived from traditional morphological techniques. The DNA-based method demonstrates significant potential as a rapid, accurate, and autonomous identification tool for B. germanica and its morphologically similar species, making it particularly valuable for quarantine inspections at ports of entry. This study establishes a foundation for the identification of B. germanica and its morphologically similar species, thereby enhancing control and management efforts. Furthermore, our findings suggest that B. asahinai is not an independent species and should be classified as a subspecies of B. germanica. While this study advances the differentiation of B. germanica from its morphologically similar species, its scope is currently limited to those found in China. Broader sampling and further in-depth research, including the incorporation of additional molecular data for large-scale comparative analysis, are necessary to effectively distinguish these similar species.

Supplementary Material

XML Treatment for Jacobsonina uncata
XML Treatment for Blattella subvittata
XML Treatment for Blattella germanica asahinai

Acknowledgements

We sincerely thank our colleagues for contributing specimens to this study. We thank Dr. John Richard Schrock for proofreading the draft.

Citation

Cai J-Z, Yao W-W, Wang Z-Q, Che Y-L (2025) On the species status of Blattella germanica and Blattella asahinai (Blattodea, Blattellidae), and other morphologically similar species. ZooKeys 1250: 155–188. https://doi.org/10.3897/zookeys.1250.145981

Funding Statement

National Natural Sciences Foundation of China (Nos. 32470462, 32170458)

Additional information

Conflict of interest

The authors have declared that no competing interests exist.

Ethical statement

No ethical statement was reported.

Use of AI

No use of AI was reported.

Funding

This study was supported by the National Natural Sciences Foundation of China (Nos. 32470462, 32170458).

Author contributions

Conceptualization: Yan-Li Che, Zong-Qing Wang. Formal analysis: Yan-Li Che, Zong-Qing Wang. Funding acquisition: Yan-Li Che, Zong-Qing Wang. Investigation: Jin-Zhuo Cai. Methodology: Yan-Li Che. Software: Yan-Li Che. Supervision: Yan-Li Che. Visualization: Jin-Zhuo Cai, Wen-Wen Yao. Writing – original draft: Jin-Zhuo Cai, Wen-Wen Yao. Writing – review and editing: Jin-Zhuo Cai, Wen-Wen Yao, Zong-Qing Wang, Yan-Li Che.

Author ORCIDs

Jin-Zhuo Cai https://orcid.org/0009-0007-2343-9517

Wen-Wen Yao https://orcid.org/0009-0006-9329-8329

Zong-Qing Wang https://orcid.org/0000-0001-9413-1105

Yan-Li Che https://orcid.org/0000-0003-3214-9494

Data availability

All of the data that support the findings of this study are available in the main text or Supplementary Information.

Supplementary materials

Supplementary material 1

Genetic distances between COI gene of B. germanica and its morphologically similar relatives

This dataset is made available under the Open Database License (http://opendatacommons.org/licenses/odbl/1.0/). The Open Database License (ODbL) is a license agreement intended to allow users to freely share, modify, and use this Dataset while maintaining this same freedom for others, provided that the original source and author(s) are credited.

Jin-Zhuo Cai, Wen-Wen Yao, Zong-Qing Wang, Yan-Li Che

Data type

xlsx

References

  1. Akinjogunla OJ, Odeyemi AT, Udoinyang EP. (2012) Cockroaches (Periplaneta americana and Blattella germanica): Reservoirs of multidrug resistant (MDR) bacteria in Uyo, Akwa Ibom State. Scientific Journal of Biological Sciences 1(2): 19–30. [Google Scholar]
  2. Asahina S. (1981) Notes on the Blattella species of Taiwan. II. What is “Ischnoptera sauteri Karny 1915?”. Japanese Journal of Sanitary Zoology 32(4): 255–259. 10.7601/mez.32.255 [DOI] [Google Scholar]
  3. Bai QK, Wang LL, Wang ZQ, Lo N, Che YL. (2018) Exploring the diversity of Asian Cryptocercus (Blattodea: Cryptocercidae): species delimitation based on chromosome numbers, morphology and molecular analysis. Invertebrate Systematics 32(1): 69–91. 10.1071/IS17003 [DOI] [Google Scholar]
  4. Bruijning CFA. (1948) Studies on Malayan Blattidae-Zool. Rijksmuseum van Natuurlijke Historie, Leiden 29: 1–174. [Google Scholar]
  5. Deng WB, Liu YC, Wang ZQ, Che YL. (2020) Eight new species of the genus Anaplecta Burmeister, 1838 (Blattodea: Blattoidea: Anaplectidae) from China based on molecular and morphological data. European Journal of Taxonomy 720: 77–106. 10.5852/ejt.2020.720.1117 [DOI] [Google Scholar]
  6. Gore JC, Schal C. (2007) Cockroach allergen biology and mitigation in the indoor environment. Annual Review of Entomology 52(1): 439–463. 10.1146/annurev.ento.52.110405.091313 [DOI] [PubMed] [Google Scholar]
  7. Han W, Qiu L, Zhu J, Wang ZQ, Che YL. (2022) Exploring the diversity of Eupolyphaga Chopard, 1929 (Blattodea, Corydioidea): Species delimitation based on morphology and molecular analysis. ZooKeys 1120: 67–94. 10.3897/zookeys.1120.87483 [DOI] [PMC free article] [PubMed] [Google Scholar]
  8. Han W, Che YL, Zhang PJ, Wang ZQ. (2024) New species of Eupolyphaga Chopard, 1929 and Pseudoeupolyphaga Qiu & Che, 2024 (Blattodea, Corydioidea, Corydiinae), with notes on their female genitalia. ZooKeys 1211: 151–191. 10.3897/zookeys.1211.128805 [DOI] [PMC free article] [PubMed] [Google Scholar]
  9. Hebard M. (1929) Studies in Malayan Blattidae (Orthoptera). Proceedings. Academy of Natural Sciences of Philadelphia 81: 1–109. [Google Scholar]
  10. Karny H. (1915) Sauter’s Formosa-Ausbeute. Orthoptera et Oothecaria. Supplementa Entomologica 4: 56–108. [Google Scholar]
  11. Kimura M. (1980) A simple method for estimating evolutionary rates of base substitutions through comparative studies of nucleotide sequences. Journal of Molecular Evolution 16(2): 111–120. 10.1007/BF01731581 [DOI] [PubMed] [Google Scholar]
  12. Klass KD. (1997) The external male genitalia and the phylogeny of Blattaria and Mantodea. Bonner Zoologische Monographien 42: 1–341. [Google Scholar]
  13. Kumar NP, Rajavel AR, Natarajan R, Jambulingam P. (2007) DNA barcodes can distinguish species of Indian mosquitoes (Diptera: Culicidae). Journal of Medical Entomology 44(1): 1–7. 10.1093/jmedent/41.5.01 [DOI] [PubMed] [Google Scholar]
  14. Lanfear R, Frandsen PB, Wright AM, Senfeld T, Calcott B. (2017) PartitionFinder 2: New methods for selecting partitioned models of evolution for molecular and morphological phylogenetic analyses. Molecular Biology and Evolution 34(3): 772–773. 10.1093/molbev/msw260 [DOI] [PubMed] [Google Scholar]
  15. Li XR, Zheng YH, Wang CC, Wang ZQ. (2018) Old method not old-fashioned: Parallelism between wing venation and wing-pad tracheation of cockroaches and a revision of terminology. Zoomorphology 137(4): 519–533. 10.1007/s00435-018-0419-6 [DOI] [Google Scholar]
  16. Li QQ, Yao WW, Zhang K, Wang ZQ, Che YL. (2023) Six new species of Margattea Shelford, 1911 (Blaberoidea, Pseudophyllodromiidae, Neoblattellini) from China. ZooKeys 1191: 339–367. 10.3897/zookeys.1191.113147 [DOI] [PMC free article] [PubMed] [Google Scholar]
  17. McKittrick FA. (1964) Evolutionary studies of cockroaches. Memoirs of the Cornell University Agricultural Experiment Station 389: 1–197. [Google Scholar]
  18. Mizukubo T. (1981) A revision of the genus Blattella (Blattaria: Blattellidae) of Japan, I. terminology of the male genitalia and description of a new species from Okinawa Island. Kyushu University Institutional Repository 17: 149–159. 10.5109/2418 [DOI] [Google Scholar]
  19. Moges F, Eshetie S, Endris M, Huruy K, Muluye D, Feleke TG, Silassie F, Ayalew G, Nagappan R. (2016) Cockroaches as a source of high bacterial pathogens with multidrug resistant strains in Gondar town, Ethiopia. BioMed Research International 2016: 1–6. 10.1155/2016/2825056 [DOI] [PMC free article] [PubMed] [Google Scholar]
  20. Naqqash MN, Saeed Q, Saeed S, Jaleel W, Zaka SM, Faheem M, Bakhtawar M, Rehman S. (2014) A cross sectional survey of community awareness about typhoid and its major vector cockroach in southern punjab, Pakistan. Middle East Journal of Scientific Research 21(4): 602–608. [Google Scholar]
  21. Nguyen LT, Schmidt HA, Von Haeseler A, Minh BQ. (2014) IQ-TREE: A fast and effective stochastic algorithm for estimating maximum-likelihood phylogenies. Molecular Biology and Evolution 32(1): 268–274. 10.1093/molbev/msu300 [DOI] [PMC free article] [PubMed] [Google Scholar]
  22. Princis K. (1950) Indomalaische und australische Blattarienaus dem Entomologischen Museum der Lund. Opuscula Entomologica 15: 161–188. [Google Scholar]
  23. Princis K. (1953) Kleine Beitröge zur Kenntnis der Blottorien und ihrer Verbreitung. Opuscula Entomologica 18: 53–58. [Google Scholar]
  24. Princis K. (1957) Zur Kenntniss der Blattarien der Kleinen Sundainseln. Verhandlungen der Naturforschenden Gesellschaft in Basel 68: 132–159. [Google Scholar]
  25. Princis K. (1969) Blattariae: Subordo Epilamproidea, Fam.: Blattellidae. Orthopterorum Catalogus 13: 712–1038. [Google Scholar]
  26. Puillandre N, Lambert A, Brouillet S, Achaz G. (2012) ABGD, automatic barcode gap discovery for primary species delimitation. Molecular Ecology 21(8): 1864–1877. 10.1111/j.1365-294X.2011.05239.x [DOI] [PubMed] [Google Scholar]
  27. Ren CH, Chen N, Li S. (2023) Harnessing “little mighty” cockroaches: Pest management and beneficial utilization. Innovation 4(6): 1–2. 10.1016/j.xinn.2023.100531 [DOI] [PMC free article] [PubMed] [Google Scholar]
  28. Richard J, Brenner RS, Patterson PG. (1988) Koehler, ecology, behavior, and distribution of Blattella asahinai (Orthoptera: Blattellidae) in central Florida. Annals of the Entomological Society of America 3(81): 432–436. 10.1093/aesa/81.3.432 [DOI] [Google Scholar]
  29. Ross MH, Mullins DE. (1988) Nymphal and oöthecal comparisons of Blattella asahinai and Blattella germanica (Dictyoptera: Blattellidae). Journal of Economic Entomology 81(6): 1645–1647. 10.1093/jee/81.6.1645 [DOI] [Google Scholar]
  30. Roth LM. (1985) A taxonomic revision of the genus Blattella Caudell (Dictyoptera: Blattaria: Blattellidae). Atherosclerosis. Supplements 22: 1–221. [Google Scholar]
  31. Roth LM. (1986) Blattella asahinai introduced into Florida (Blattaria: Blattellidae). Psyche 93(3–4): 371–374. 10.1155/1986/60130 [DOI] [Google Scholar]
  32. Roth LM. (2003) Systematics and phylogeny of cockroaches (Dictyoptera: Blattaria). Oriental Insects 37(1): 1–186. 10.1080/00305316.2003.10417344 [DOI] [Google Scholar]
  33. Santos ABR, Chapman MD, Aalberse RC, Vailes LD, Ferriani VP, Oliver C, Rizzo MC, Naspitz CK, Arruda LK. (1999) Cockroach allergens and asthma in Brazil: Identification of tropomyosin as a major allergen with potential cross-reactivity with mite and shrimp allergens. The Journal of Allergy and Clinical Immunology 104(2): 329–337. 10.1016/S0091-6749(99)70375-1 [DOI] [PubMed] [Google Scholar]
  34. Tang Q, Bourguignon T, Willenmse L, De Coninck E, Evans TA. (2019) Global spread of the German cockroach, Blattella germanica. Biological Invasions 21(3): 693–707. 10.1007/s10530-018-1865-2 [DOI] [Google Scholar]
  35. Tang Q, Vargo EL, Ahmad I, Jiang H, Varadínová ZK, Dovih P, Kim D, Bourguignon T, Booth W, Schal C, Mukha DV, Rheindt FE, Evans TA. (2024) Solving the 250-year-old mystery of the origin and global spread of the German cockroach, Blattella germanica. Proceedings of the National Academy of Sciences of the United States of America 121(22): 1–3. 10.1073/pnas.2401185121 [DOI] [PMC free article] [PubMed] [Google Scholar]
  36. Wang ZQ, Jiang HY, Che YL. (2009) Two new species and one new record of the genus Jacobsonina Hebard (Blattaria, Blattellidea) from China. Dong Wu Fen Lei Xue Bao 34(4): 751–756. [Google Scholar]
  37. Wang ZQ, Che YL, Feng PZ. (2010) The taxonomic study of the genus Blattella Caudell 1903 from China with description of one new species (Blattaria: Blattellidae). Acta Entomologica Sinica 53(8): 908–913. [Google Scholar]
  38. Wang YS, Chen R, Jin DT, Che YL, Wang ZQ. (2021) New record of Cyrtonotula Uvarov, 1939 (Blaberidae, Epilamprinae) from China, with three new species based on morphological and COI data. ZooKeys 1021: 127–143. 10.3897/zookeys.1021.59526 [DOI] [PMC free article] [PubMed] [Google Scholar]
  39. Wang YS, Zhang JW, Lo N, Bourguignon T, Guo L, Li BL, Che Y-L, Wang Z-Q. (2023) Phylogenetic analysis of Blaberoidea reveals non‐monophyly of taxa and supports the creation of multiple new subfamilies. Cladistics 39(3): 198–214. 10.1111/cla.12535 [DOI] [PubMed] [Google Scholar]
  40. Yao WW, Li QQ, Li LW, Wang ZQ, Che YL. (2024) Discovery of four new Chinese species of Jacobsonina Hebard, 1929 and Blattella Caudell, 1903 (Blaberoidea: Blattellidae). Zootaxa 5474(4): 427–440. 10.11646/zootaxa.5474.4.5 [DOI] [PubMed] [Google Scholar]
  41. Zhang D, Gao F, Jakovlic I, Zo H, Zhang J, Li WX, Wang GT. (2020) PhyloSuite: An integrated and scalable desktop platform for streamlined molecular sequence data management and evolutionary phylogenetics studies. Molecular Ecology Resources 20(1): 348–355. 10.1111/1755-0998.13096 [DOI] [PubMed] [Google Scholar]
  42. Zhu J, Zhang JW, Luo XX, Wang ZQ, Che YL. (2022) Three cryptic Anaplecta (Blattodea, Blattoidea, Anaplectidae) species revealed by female genitalia, plus seven new species from China. ZooKeys 1080: 53–97. 10.3897/zookeys.1080.74286 [DOI] [PMC free article] [PubMed] [Google Scholar]

Associated Data

This section collects any data citations, data availability statements, or supplementary materials included in this article.

Supplementary Materials

XML Treatment for Jacobsonina uncata
zookeys.1250.145981-treatment1.xml (10.6KB, xml)
XML Treatment for Blattella subvittata
zookeys.1250.145981-treatment2.xml (11.5KB, xml)
XML Treatment for Blattella germanica asahinai
zookeys.1250.145981-treatment3.xml (12.5KB, xml)
Supplementary material 1

Genetic distances between COI gene of B. germanica and its morphologically similar relatives

This dataset is made available under the Open Database License (http://opendatacommons.org/licenses/odbl/1.0/). The Open Database License (ODbL) is a license agreement intended to allow users to freely share, modify, and use this Dataset while maintaining this same freedom for others, provided that the original source and author(s) are credited.

Jin-Zhuo Cai, Wen-Wen Yao, Zong-Qing Wang, Yan-Li Che

Data type

xlsx

zookeys-1250-155_article-145981__-s001.xlsx (39.8KB, xlsx)

Data Availability Statement

All of the data that support the findings of this study are available in the main text or Supplementary Information.

Articles from ZooKeys are provided here courtesy of Pensoft Publishers

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