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. 2016 Nov 24;(636):51–65. doi: 10.3897/zookeys.636.10592

A new earwig of the genus Echinosoma from Penang Island, Peninsular Malaysia, with notes on the taxonomic and nomenclatural problems of the genus Cranopygia (Insecta, Dermaptera, Pygidicranidae)

Yoshitaka Kamimura 1,2, Masaru Nishikawa 3, Chow-Yang Lee 2
PMCID: PMC5126516  PMID: 27917064

Abstract Abstract

The pygidicranid earwigs (Dermaptera) of Penang Island, Peninsular Malaysia were re-examined based on material collected in extensive field surveys in 2012–2013 and 2015. Echinosoma roseiventre Kamimura & Nishikawa, sp. n. is described and illustrated, and Cranopygia pallidipennis (de Haan, 1842) is reported from the island for the first time. The taxonomic and nomenclatural problems of the genus Cranopygia sensu Hincks (1959) [A Systematic Monograph of the Dermaptera of the World. Part II. Pygidicranidae excluding Diplatyinae. British Museum (Natural History)] are also discussed. For the members of the subfamily Pygidicraninae from Indo-Austral and Oriental regions, the system, definitions of genera, and key of Hincks (1959) are followed. The genus Mucrocranopygia Steinmann, 1986 is synonymized with Cranopygia Burr, 1908. A key to the males of small Echinosoma from the Oriental region is provided.

Keywords: Cranopygia pallidipennis, Cranopygia similis, Echinosoma roseiventre, south-east Asia

Introduction

Penang Island (Pulau Pinang) is a 299-km2 island located in the Straits of Malacca, approximately 5 km from the western coast of the mainland of Peninsular Malaysia. Thirty-one species of Dermaptera (earwigs) from this small tropical island are reported, based on an extensive field survey conducted in 2012–2013 (Kamimura et al. 2016), including an undescribed species of the genus Echinosoma Audinet-Serville, 1839 (Pygidicranidae). An additional field survey by the first author (YK) in 2014 resulted in the discovery of a species from the genus Cranopygia Burr, 1908 (Pygidicranidae) sensu Hincks (1959), which was not collected during the 2012–2013 survey (Kamimura et al. 2016). Cranopygia similis (Zacher, 1911) was recorded from “Penang” (Burr 1910, Hincks 1959) in the early 20th century, although whether it was collected on the island or from the mainland state of Penang is unclear. Based on a comparison of the samples collected during our surveys with material preserved in museums, the identity of Cranopygia from Penang Island is discussed, as well as the taxonomic and nomenclatural problems of the genus Cranopygia sensu Hincks (1959).

Methods

An extensive field survey of earwigs was conducted on Penang Island from March 2012 to March 2013 (see Kamimura et al. 2016 for details). Based on the samples collected during this survey a new species of Echinosoma is described. The type material of the new species and some representative samples collected during this study will be deposited in the collections of the Osaka Museum of Natural History (OMNH; Osaka, Japan) and the Lee Kong Chian Natural History Museum (LKCNHM; Singapore).

An additional field survey was conducted by YK on 9–13 March, 2015, during which time two Cranopygia samples were collected from Bukit Jambul (5.348821N, 100.285692E). The site is a hill with a maximum elevation of approximately 200 m a.s.l that is covered with plantations of rubber, durian, banana, and other fruit trees, and is surrounded by secondary forests. A nymphal sample collected this location was reared to adulthood in the laboratory. For comparison, we examined specimens of Cranopygia species from Manchester Museum (MM) and the Natural History Museum (NHM), UK, and the entomological specimen collections of the School of Biological Sciences, Univerisiti Sains Malaysia, Penang, Malaysia.

Male and female genitalia removed from the examined specimens were mounted in Euparal (Waldeck GmbH & Co. KG, Münster, Germany) between two cover slips, and attached to the pin of the respective specimen. The terminologies of Klass (2003) and Kamimura (2014) are used for female and male genital structures, respectively.

Taxonomy

Genus Echinosoma Audinet-Serville, 1839

Echinosoma roseiventre

Kamimura & Nishikawa sp. n.

http://zoobank.org/A1DA37A5-838E-4B46-A5A1-977893C9460A

Figs 1a , 2–6 , 7–9

Figure 1.

Figure 1.

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Holotype (male) of Echinosoma roseiventre sp. n. (a), a male (b–d) and a female (e–f) of Cranopygia pallidipennis from Penang Island, and a male of Cranopygia similis from Java (MM No. 3639) (g–i). (a, b, e, g) habitus; (c, d, h, i) male genitalia; (f) female genitalic region and ovipositor. The red and blue arrowheads indicate the expanded outer angle of the parameres (c) and the distal process of the virgae (c, d, i), respectively. Abbreviations: AP; ce; gl8; gl9; gp8; gp9; LC9; LP; TG8–TG10. Scale bars: 3 mm in a, b, e, and g; 1 mm in c, f and h; 200 µm in d and i.

Figures 2–6.

Figures 2–6.

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Echinosoma roseiventre sp. n. Holotype (male) 2 Head and thorax 3 The basal part of left antenna 4 Penultimate sternite (pubescence omitted) 5 Ultimate tergite and forceps 6 Genitalia (before mounting in Euparal). Scale bars: 0.5 mm.

Figures 7–9.

Figures 7–9.

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Echinosoma roseiventre sp. n. Holotype (male). 7 Right paramere 8 The tip of right virga 9 The base of right virga (indicated by the gray arrowhead) with the funnel-shaped sclerite (indicated by the solid arrowhead) and the long ellipse sclerite (indicated by the open arrowhead). Scale bars: 200 µm.

Diagnosis.

Echinosoma roseiventre sp. n. is a small species less than 8 mm including the forceps. This species differs from all other similar sized species of Echinosoma with the combination of the following characters: abdomen uniformly reddish brown or rosy without a distinct pattern; ultimate tergite not pubescent, but with small rounded swellings; pygidium broader than long; virga very long, more than five times longer than parameres, tubular and simple.

Description.

Holotype (male): length of body (without forceps): 7 mm. Length of forceps: 0.9 mm. Head width: 1.5 mm. Pronotum width: 1.6 mm. Pronotum length: 1.1 mm.

Color: General body color dull smoky black but abdomen, especially caudal part, pygidium, and forceps reddish brown or rosy (Fig. 1a). Mouth parts brownish. Antennae dark brown except for first three segments dirty white. Legs dirty white but femora with a broad fuscous band near the base. Caudal margin of tegmina with distinct, narrow whitish band. First abdominal segment whitish. Body covered with obtuse bristles sparsely. Head (Fig. 2) slightly broader than long; frons convex; transverse and median suture indistinct; caudal margin feebly emarginated in middle. Antennae (Fig. 3); 17 segments (left side partly broken, 16 segments remaining), segments mostly stout; 1st expanded apically, nearly half long as the distance between antennal bases; 2nd short, quadrate, almost as long as broad; 3rd long, twice as long as broad; 4th and 5th short, as long as broad; 6th and beyond gradually becoming longer and narrowing basally rendering some segments subpyriform. Eyes long, approx. as long as the post-ocular length. Post-ocular margin with a row of five long bristles. Pronotum (Fig. 2) broader than long; surface rough; sides rounded; frontal and caudal angles weakly and strongly rounded, respectively; caudal margin convex with distinct emargination in middle; prozona distinctively raised; median sulcus week but visible; row of long bristles on frontal and lateral margins. Tegmina almost as long as pronotum; surface rough; humeral angle weak and anal angle shortly rounded off to show a small, triangular scutellum; caudal margin obliquely truncate, outer and caudal margins with long bristles. Hind wings wanting. Legs stout; femora not compresed, ecarinate; arolium small; hind tarsi with 1st segment longer than the third. Abdomen stout, more or less parallel-sided, except first three segments narrowed; sides of segments almost straight; tergites with scattered granules or very short obtuse bristles with whitish apex; first two tergites and lateral sides of 3rd tergites onward with long bristles near caudal margins. Penultimate sternite (Fig. 4) transverse, narrowed posteriorly with caudal margin being nearly half of the anterior, widely emarginated. Ultimate tergite (Fig. 5) transverse, with small rounded swellings above the base of forceps; caudal margin almost straight. Pygidium short, rectangular, transverse. Forceps (Fig. 5) short, strongly curving inwards, tapering apically; surface, smooth at tips. Genitalia (Figs 6–9) with slender, finger-like parameres with obtuse tips and broad base (Fig. 7); penis lobe almost twice length of parameres; virga very long, more than five times longer than parameres, tubular and simple (Figs 6, 8); penis lobes also enclose a funnel-shaped sclerite at the base of virga, and a long ellipse sclerite distally (Fig. 9).

Paratype (male). Length of body (without forceps), 6.5 mm; length of forceps, 0.8 mm; head width, 1.2 mm; pronotum width, 1.2 mm; pronotum length, 0.8 mm. Antennae broken, five (right) and eleven (left) segments remaining. Tegmina longer, approx. 1.5 times longer than pronotum. Penultimate sternite not strongly narrows posteriorly, almost rectangular.

Female. Unknown.

Type series.

Holotype: 1 male (genitalia mounted in Euparal between two coverslips and attached to the pin of the specimen), Bukit Jambul, Penang Island, West Malaysia, 27.XI.2012, Y. Kamimura leg. [OMNH]. Paratype: 1 male (genitalia mounted in Euparal between two coverslips and attached to the pin of the specimen), same locality as holotype, 24.VI.2012 (8.VII.2012 emerged from a nymph), Y. Kamimura leg. [LKCNHM].

Distribution.

Penang Island, Peninsular Malaysia

Etymology.

The specific epithet refers to the characteristic rosy abdomen of this new species.

Remarks.

Echinosoma roseiventre sp. n. is very close to Echinosoma andamanensis Srivastava, 1988, described from India. Currently these two species can only be distinguished by differences in the length of the virgae (shorter than five times the parameres in Echinosoma andamanensis), the shape of the pygidium (longer than broad in Echinosoma andamanensis), and body coloration (Echinosoma andamanensis is generally dull smoky black but the abdomen, pygidium, and forceps are shiny; Srivastava 1988).

In addition to the species listed in the key below, Echinosoma rufomarginatum Borelli, 1931, which Hincks (1959), Steinmann (1986) and Srivastava (1988) treated as a doubtful species, also has a small body size (body length with forceps of ~11 mm; Hincks 1959). However, according to the original description by Borelli (1931), the male penultimate sternite of this species has a very deep emargination on the caudal margin. The male genitalia of Echinosoma burri Hincks, 1959, recorded from Java and Sumatra, are very similar to those of Echinosoma roseiventre sp. n., but the body size is much larger (male body length with forceps of 18–20 mm; Hincks 1959).

Key to the small Echinosoma species (body length + forceps = 10 mm or less) from the Oriental Region (males only)

1 Abdomen with distinct pattern consisting of three light longitudinal stripes or series of spots 2
– Abdomen more or less uniformly colored, without distinct pattern 4
2 Sides of pronotum rounded. Virga almost straight Echinosoma affine Hincks, 1959
– Sides of pronotum straight, parallel. 3
3 Virga slightly undulate Echinosoma trilineatum Borelli, 1921
– Virga very long, convoluted Echinosoma sarawacense Borelli, 1959
4 Pygidium characteristic, forming a large rounded lobe, filling the space between forceps, produced into a sharp pointed spine above posteriorly Echinosoma maai Srivastava, 2003
– Pygidium normal, without a sharp pointed spine above posteriorly 5
5 Ultimate tergite with long pubescence 6
– Ultimate tergite setose or with very short, sparse, adpressed setae 8
6 Virga not longer than penis lobe Echinosoma sumatranum (de Haan, 1842)
– Virga longer than penis lobe 7
7 Virga convoluted Echinosoma convolutum Hincks, 1959
– Virga almost straight, not convoluted Echinosoma komodense Bey-Bienko, 1970
8 Virga not longer than penis lobe 9
– Virga longer than penis lobe 10
9 Penis lobe with long strong bristles (or toothed pad) beside virga Echinosoma setulosum Hincks, 1959
– Penis lobes without long strong bristles (or toothed pad) Echinosoma parvulum Dohrn, 1863
10 Virgae shorter than five times of parameres in length. Pygidium longer than broad Echinosoma andamanensis Srivastava, 1988
– Virgae longer than five times of parameres in length. Pygidium broader than long Echinosoma roseiventre sp. n.
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Genus. Cranopygia

Burr sensu Hincks (1955)

  • Cranopygia pallidipennis (de Haan, 1842)

Material examined.

Male, preserved in the collection of the laboratory of entomology (Makmal Entomologi), School of Biological Sciences, Universiti Sains Malaysia: Taman Rimba (Teluk Bahang Recreational Park), Penang Island, 9 XII 2009, Tan Chia Chi leg. The specimen has now been transferred to the entomological specimen collections of the School of Biological Sciences, Universiti Sains Malaysia. Two females (one emerged from nymph on 30 III 2015): Bukit Jambul (secondary forest of a rubber plantation), Penang Island, 11 III 2015, Y. Kamimura leg.

Comparative material examined.

Cranopygia similis (Zacher, 1911): Male, preserved in the collection of the Manchester Museum, the University of Manchester, England: “H. LUCHT, K. O. Blawan, 900/1500 Mr., Idjan Plateau [with unreadable handwritten characters: ? 205.39] / 3639 / Cranopygia similis (Zacher) ♂, det W. D. Hinks” [MM No. 3639].

Known distribution.

Malaysia (Kuala Lumpur, Bukit Kuru), Myanmar, Indonesia (Java, Sumatra, Borneo).

Remarks.

First record for Penang Island.

Discussion

Problems in the taxonomic treatment of Cranopygia Burr sensu Hincks (1955)

Within the family Pygidicranidae, the subfamily Pygidicraninae Verhoeff, 1902 is characterized by a medium to large body size (rarely less than 20 mm), antennae with 25 segments or more in which the 4th and 5th are wider than they are long, depressed femora, and equally developed right and left penis lobes (Burr 1915a, Hincks 1955, Steinmann 1986, Srivastava 1988). Indo–Austral and Oriental species of this subfamily are usually classified in the genus Tagalina Dohrn, 1863, in which the second tarsal segments are characteristically enlarged, or the genus Cranopygia Burr, 1908 sensu Hincks (1955). The taxonomy of the latter is rather unstable and unsettled. Including this group, for several species that were formerly in the genus Pygidicrana Audinet-Serville, 1831, Burr (1908) erected the following four genera based on differences in the shapes of the penultimate sternite, pronotum, and elytra: Cranopygia (type species, Pygidicrana cumingi Dohrn, 1863), Pyge (type species, Pygidicrana modesta de Bormans, 1894), Dicrana (type species, Pygidicrana frontalis Kirby, 1903), and Picrania (type species, Pygidicrana liturata Stål, 1855). Subsequently, Zacher (1911) established the genus Kalocrania (type species: Pygidicrana marmoricrura Audinet-Serville, 1839), to which two additional species of Oriental Pygidicrana were transferred, with the description of a new species. However, the species of Cranopygia sensu Burr (1908) were apparently unknown to Zacher, which resulted in a lack of agreement as to how to distinguish between Cranopygia and Kalocrania (see Hincks 1955 for more details). To settle this problem, Burr (1915a) consistently examined the male genitalia of this group for the first time, and redefined the genus Cranopygia based on the shape of the virga. Simultaneously, Pyge was synonymized with Kalocrania, and a new genus Acrania was established (type species, Pygidicrana picta Guérin-Méneville, 1838). Hincks (1955), who examined the genital armatures for many more species in this group, concluded that Cranopygia, Kalocrania, and Acrania could not consistently be distinguished based on their genital morphologies, and he later synonymized the latter two genera with Cranopygia, with the formation of five species groups (Hincks 1959). Several species formerly in the genus Dicrana were also included in Cranopygia by Hincks (1959).

Nearly 25 years later, Steinmann (1986) erected three new genera, Epicranopygia (type species: Pygidicrana picta Guérin-Méneville, 1838), Mucrocranopygia (type species: Pygidicrana horsfieldi Kirby, 1891), and Paracranopygia (type species: Forficula pallidipennis de Haan, 1842), for the species of Cranopygia sensu Hincks (1959) with virgae that were not straight. Srivastava (1993a) considered that the traits for diagnosing these genera (i.e., the shapes of the penis lobes and the virgae) were unstable and therefore unsuitable for generic classification. Instead, he focused on the shape of the parameres, which are robust and resistant to the artifacts of mounting, and reinstated Acrania for species with parameres that are neither knobbed nor hooked externally or internally (but occasionally with a slight convexity of the external apical angle).

Engel and Haas (2007), who omitted to cite Srivastava (1993a), noted that the generic names Acrania and Pyge, which Steinmann (1986) considered invalid, were available for the group containing the respective type species. Accordingly, they reinstated Acrania and Pyge, making Epicranopygia and Paracranopygia junior objective synonyms. Although they did not provide the species lists for Cranopygia and Mucrocranopygia (sensu Steinmann 1986), Engel and Haas (2007) followed Steinmann’s (1986) taxonomic system for the subfamily, except for the abovementioned changes in generic names.

Srivastava’s (1993a) taxonomic treatment is also problematic. He reinstated Acrania, the type species of which is Pygidicrana picta Guérin-Méneville, 1838. However, he simultaneously synonymized Epicranopygia, which was created with the same type species (Pygidicrana picta), with Cranopygia. According to his list of new combinations, Srivastava (1993a) transferred three species of Epicranopygia to Cranopygia, but transferred three others, including Echinosoma picta, to Acrania. Thus, the declaration of synonyms in Srivastava (1993a), and those cited in subsequent papers (Srivastava 1993b, 1995) are incorrect: Srivastava (1993a) synomyzed Epicranopygia (pars) and Paracranopygia (pars) with Acrania and Cranopygia.

Subsequently, Sakai (1996, 2000) generally followed Srivastava’s (1993a) system (and possibly the identification key), but concurrently adopted Hincks’s (1959) species-group level classification. However, instead of using the Cranopygia siamensis species group (Hincks 1959), he treated Paracranopygia as a valid subgenus for most species of Paracranopygia sensu Steinmann (1986), as well as including Cranopygia tianshanskyi and Cranopygia chirurga, which were originally described by Gorochov and Anisyutkin (1993) under the genus Paracranopygia.

In addition to these nomenclatural problems, recent studies have shown that the morphology of earwig virgae, particularly the length, evolves rapidly due to sperm competition, resulting in considerable variation even among very closely related congeners (Kamimura 2000, 2014, Lieshout and Elgar 2011). Therefore, although useful for species diagnosis, generic classification systems based primarily on virgal characteristics (e.g., length, convolution) likely do not reflect accurately the phylogenetic relationships. In contrast, the functional significance of male genital parameres is largely unknown for earwigs (Kamimura 2014). Nevertheless, the presence or absence of a tooth or process of the parameres, which Srivastava (1993a) proposed to distinguish Cranopygia and Acrania, is also likely an unreliable trait for the generic classification of this group. For example, male Cranopygia vittipennis Hincks, 1955 have a tiny process at the outer angle of the paramere, whereas a similar but weaker process is found in Acrania luzonica (Brindle, 1955) in the equivalent position (compare figs. 2 and 12 of Srivastava 1993a). A similar observation was made for Cranopygia pallidipennis from Penang Island, which is described below. Therefore, for the taxonomy of pygidicranine earwigs, we propose to follow the system, definitions of the genera, and key of Hincks (1959); that is, all of the species from Indo–Austral and Oriental regions (except for some species of Dacnodes) are classified either in the genera Tagalina (species with an enlarged second tarsal segment) or Cranopygia (species with a simple second tarsal segment). Accordingly, we propose to place all of the following species in the genus Cranopygia.

Genus Cranopygia Burr and its synonyms

Cranopygia Burr, 1908: 384, 389 [type-species: Pygidicrana cumingi Dohrn, 1868 (original designation)]; 1910: 53, 61; 1911: 16, 19; 1915a: 432, 435 (Pyge Burr, proposed synonymy with Cranopygia Burr). – Townes 1945: 346 (catalogue). – Hincks 1955: 809 (Kalocrania Zacher and Acrania Burr, proposed synonymy with Cranopygia); 1959: 52 (revision). – Popham 1965: 132 (in key). – Brindle 1970: 647. – Sakai 1971: 12 (catalogue); 1982: 15 (list of species); 1996: 3 (list of species); 2000: 89 (in key). – Steinmann 1973a: 148 (list); 1973b: 396 (in key); 1975: 202 (in key); 1983: 56 (synopsis); 1986: 240 (revision); 1989: 122 (catalogue). – Srivastava 1988: 37 (classification same as Hincks 1959); 1993a (1992): 43 (Epicranopygia Steinmann and Paracranopygia Steinmann, proposed synonymy with Cranopygia); 1995: 293 (Epicranopygia Steinmann and Paracranopygia Steinmann, as synonyms of Cranopygia).

Pygidicrana (pars) Audinet-Serville, 1831: 30 [type-species: Pygidicrana v-nigrum Audinet-Serville, 1831 (Monobasic)]; 1839: 19. – Dohrn 1863: 46. – Scudder 1876: 298. – de Bormans and Kraus 1900: 15. – Kirby 1904: 4. – Burr 1908: 384; 1910: 53.

Pyge (pars) Burr, 1908: 384, 390 [type-species: Pygidicrana modesta de Bormans, 1894 (original designation)]; 1910: 53, 65; 1911: 16, 20; 1915a: 435. – Shiraki 1928: 3. – Townes 1945: 354 (catalogue). – Engel and Haas 2007: 19 (Paracranopygia Steinmann, proposed synonymy with Pyge).

Dicrana (pars) Burr, 1908: 384, 387 [type-species: Pygidicrana frontalis Kirby, 1903 (original designation)]; 1910: 53, 60; 1911: 16, 19. – Townes 1945: 347 (catalogue).

Picrania (pars) Burr, 1908: 390 [type-species: Pygidicrana liturata Stål, 1855 (original designation)]; 1910: 53, 63; 1911: 16, 19. – Townes 1945: 353 (catalogue).

Kalocrania Zacher, 1910: 105 [type-species: Pygidicrana marmoricrura Audinet-Serville, 1839 (original designation)]. – Zacher 1911: 335, 336. – Burr 1911: 16, 18 (pars), pl. 8, fig. 18 (opisthomeres); 1915a: 432, 435; 1915b: 258, fig. 1 (opisthmeres), fig. 19 (gonapophyses). – Townes 1945: 350 (catalogue).

Acrania Burr, 1915a: 432, 436 [Type species: Pygidicrana picta Guérin-Méneville, 1838 (original designation)]. – Townes 1945: 343 (catalogue). – Srivastava 1993a (1992): 44 (Mucrocranopygia Steinmann, proposed synonymy with Acrania); 1993b: 373 (Mucrocranopygia Steinmann and Epicranopygia Steinmann (pars), as synonyms of Acrania); 1995: 293 (Mucrocranopygia Steinmann, as synonym of Acrania). – Sakai 1996: 2 (list of species); 2000: 100 (in key). – Engel and Haas 2007: 19 (Epicranopygia Steinmann, proposed synonymy with Acrania).

Epicranopygia Steinmann, 1986: 269 (proposed new name for Acrania Burr, 1915) [type-species: Pygidicrana picta Guérin-Méneville, 1838 (original designation)]; 1989: 146 (catalogue). – Sakai 1982: 16 (list of species).

Paracranopygia Steinmann, 1986: 277 [type-species: Forficula pallidipennis de Haan, 1842 (original designation)]; 1989: 150 (catalogue). – Sakai 1982: 15 (list of species).

Cranopygia (Paracranopygia) Sakai, 1996: 4 [= siamensis-group, Hincks (1959)] (list of species); 2000: 104 (in key).

Mucrocranopygia Steinmann, 1986: 266 [type-species: Pygidicrana horsfieldi Kirby, 1891 (original designation)]; 1989: 149 (catalogue). – Sakai 1982: 15 (list of species). New synonym.

List of species to be included in the genus Cranopygia

Cranopygia angustata (Dohrn, 1862); Cranopygia appendiculata Hincks, 1955; Cranopygia assamensis Hincks, 1955; Cranopygia bakeri (Borelli, 1921); Cranopygia beybienkoi Gorochov & Anisyutkin, 1993; Cranopygia bhallaie Kapoor, 1966; Cranopygia bifurcata Srivastava, 1980; Cranopygia brindlei Srivastava, 1988; Cranopygia burmensis Hincks, 1955; Cranopygia burri Hincks, 1955; Cranopygia carinata Hincks, 1959; Cranopygia celebensis (de Bormans, 1903); Cranopygia chirurga (Gorochov & Anisyutkin, 1993); Cranopygia comata Hincks, 1955; Cranopygia constricta Hincks, 1955; Cranopygia corymbifera Anisyutkin, 1997; Cranopygia crockeri Anisyutkin, 2014; Cranopygia cumingi (Dohrn, 1862); Cranopygia curtula Hincks, 1955; Cranopygia daemeli (Dohrn, 1869); Cranopygia dravidia (Burr, 1914); Cranopygia eximia (Dohrn, 1862); Cranopygia fletcheri Bharadwaj & Kapoor, 1967; Cranopygia formosa Hincks, 1955; Cranopygia gialaiensis Gorochov & Anisyutkin, 1993; Cranopygia guttata (Kirby, 1903); Cranopygia horsfieldi (Kirby, 1891); Cranopygia imperatrix (Burr, 1899); Cranopygia jacobsoni (Boeseman, 1954); Cranopygia javana Hincks, 1955; Cranopygia kallipygos (Dohrn, 1862); Cranopygia lueddemanni Srivastava, 1984; Cranopygia luzonica Brindle, 1967; Cranopygia maculipes Hincks, 1955; Cranopygia manipurensis Srivastava, 1975; Cranopygia marmoricrura (Audinet-Serville, 1839); Cranopygia modesta (de Bormans, 1894); Cranopygia nietneri (Dohrn, 1862); Cranopygia nova Anisyutkin, 2015; Cranopygia okunii (Shiraki, 1928); Cranopygia ophthalmica (Dohrn, 1862); Cranopygia pallidipennis (de Haan, 1842); Cranopygia parva Brindle, 1975; Cranopygia philippinica Burr, 1914; Cranopygia picta (Guerin-Méneville, 1838); Cranopygia pluto Hebard, 1923; Cranopygia proxima Hincks, 1959; Cranopygia raja (Burr, 1911); Cranopygia rostrata Brindle, 1970; Cranopygia sarawacensis Hincks, 1959; Cranopygia sauteri (Burr, 1912); Cranopygia semenoffi (Burr, 1912); Cranopygia siamensis (Dohrn, 1862); Cranopygia similis (Zacher, 1911); Cranopygia spenceri Srivastava, 2003; Cranopygia steineri Srivastava, 1993; Cranopygia steinmanni Srivastava, 1988; Cranopygia tianshanskyi (Gorochov & Anisyutkin, 1993); Cranopygia tonkinensis Hincks, 1955; Cranopygia tumida Borelli, 1931; Cranopygia valida (Dohrn, 1867); Cranopygia vanderdoesi Boeseman, 1954; Cranopygia variegata Brindle, 1965; Cranopygia vicina Hincks, 1959; Cranopygia vietnamensis Gorochov & Anisyutkin, 1993; Cranopygia vitticollis (Stål, 1855); Cranopygia vittipennis Hincks, 1955.

Identification of specimens of Cranopygia from Penang

The external morphology, coloration, and genitalia of the male specimen collected at Taman Rimba (Teluk Bahang Recreational Park), Penang Island are very similar to those of Cranopygia pallidipennis (de Haan, 1842) described by de Haan (1842), Burr (1910), Zacher (1911), and Hincks (1959) (Fig. 1b-d). The external morphologies and coloration of the female specimens from Bukit Jambul, Penang Island also match the descriptions of Cranopygia pallidipennis (de Haan 1842, de Bormans and Kraus 1900, Zacher 1911, Hincks 1959). The female genital region was also examined for a female specimen that emerged in the laboratory (Fig. 1f). Although the female genitalia are rarely described for the genus (but see Zacher 1911; Anisyutkin 2014) and thus diagnostic features have not been established, the observed morphology (Fig. 1f) matches that described by Zacher (1911) for Cranopygia pallidipennis.

A male specimen of Cranopygia was recorded from “Penang” in the early 20th century (Burr 1910; Hincks 1959). Burr (1910) identified it as Cranopygia siamensis (Dohrn, 1863). Later, Hincks (1959) tentatively identified the specimen as Cranopygia similis (Zacher, 1911) based on features of the genitalia. However, according to Hincks (1959), the large body size (36 mm) of the specimen and the following external morphology are not typical of Cranopygia similis; “In the Penang male the pronotum is as broad as long, and the sides are strongly rounded; the occiput is marmorated with fuscous dots and streaks; the pronotum has the dark bands much more broken; the femora are dotted with fuscous and not longitudinally streaked; the forceps are rather longer and more curved, enclosing an oblong–ovate space.” Some of these characteristics suggest a very close affinity of the specimen to Cranopygia pallidipennis, but the shape of the forceps is different (Burr 1910).

Cranopygia pallidipennis seems to be very close to Cranopygia similis and can be distinguished from the latter by a larger body size; the pattern of fuscous markings on the head, pronotum, and femora (Fig. 1b, e vs. Fig. 1g); a larger space enclosed by the distal part of the forceps (Fig. 1b vs. Fig. 1g); a less pronounced convexity at the outer angle of the parameres (Fig. 1c vs. Fig. 1h); and the presence of a single, long filamentous projection at the tip of the virgae (Fig. 1d vs. Fig. 1i). The last characteristic is likely a diagnostic feature distinguishing Cranopygia pallidipennis from Cranopygia similis. Unfortunately, we could not reexamine the male specimen from “Penang” described by Burr (1910) as it is currently missing; it was not found in the collections of the NHM (including Burr’s collection) or the MM. In conclusion, our study shows that Cranopygia pallidipennis is a member of the contemporary earwig fauna of the island, whereas the identity of Burr’s specimen of Cranopygia from “Penang” requires further investigation including determining the exact location from which it was collected.

Supplementary Material

XML Treatment for Echinosoma roseiventre
zookeys.636.10592-treatment1.xml (20.3KB, xml)
XML Treatment for Cranopygia
zookeys.636.10592-treatment2.xml (4.3KB, xml)

Acknowledgments

This study was conducted with the approval of the Economic Planning Unit, Malaysia (Reference No. UPE: 40/200/19/2844). We thank D.V. Logunov, G. Beccaloni, S. Khatijah, and C.L. Liew for helping us with specimen examination, and L.N. Anisyutkin and P. Kočárek for useful comments on a previous version of the manuscript. This study was partly supported by a grant for overseas research from Keio University to Y.K. and a Grant-in-Aid for Scientific Research to Y.K. (Kakenhi, Nos. 22770058 and 15K07133) from the Japan Society for the Promotion of Science.

Citation

Kamimura Y, Nishikawa M, Lee C-Y (2016) A new earwig of the genus Echinosoma from Penang Island, Peninsular Malaysia, with notes on the taxonomic and nomenclatural problems of the genus Cranopygia (Insecta, Dermaptera, Pygidicranidae). ZooKeys 636: 51–65. doi: 10.3897/zookeys.636.10592

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Associated Data

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

Supplementary Materials

XML Treatment for Echinosoma roseiventre
zookeys.636.10592-treatment1.xml (20.3KB, xml)
XML Treatment for Cranopygia
zookeys.636.10592-treatment2.xml (4.3KB, xml)

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