AnimaliaColeopteraHydrophilidaeSmithRachel R.ShortAndrew Edward Z.Review of the genus Chasmogenus Sharp, 1882 of northeastern South America with an emphasis on Venezuela, Suriname, and Guyana (Coleoptera, Hydrophilidae, Acidocerinae)Zookeys1952020934257910.3897/zookeys.934.493598953983E-25C9-5B6B-9AF3-2CE9DC81098E Chasmogenus clavijoi http://zoobank.org/02C1D58C-E5EC-493D-A4E4-182972AD729B sp. nov.Figures 9D, 14B, 17, 20BMaterial examined.

Holotype (male): “Venezuela: Guárico State/ 8°8.296'N, 66°24.459'W/ San Nicolasito Field Station/ 10.i.2009; leg. Short & Miller/ VZ09-0110-02X; morichal”/ “[barcode]/ SEMC0855289/ KUNHM-ENT”, “HOLOTYPE/ CHASMOGENUS/ clavijoi sp. n./ des. Smith & Short” (MIZA). Paratypes (5): same data as holotype (5 exs. SEMC, including DNA voucher SLE1198).

10.3897/zookeys.934.49359.figure14A22CFA6D-CC03-5534-BB5E-F52714B400B0

Aedeagi of (dorsal view) of Chasmogenus spp. AC. ampliusBC. clavijoiCC. gatoDC. berbicensisEC. brownsbergensisFC. schmitsG, HC. guianensisG specimen from Suriname H specimen from Guyana. Scale bar: 0.25 mm.

https://binary.pensoft.net/fig/411769
Differential diagnosis.

Though C. clavijoi shares a smaller body size and similar morphology as C. gato, it may be differentiated by the paler dorsal coloration.

Description.

Size and color. Total body length 3.8–4.5 mm. Body form elongate oval with slightly curved lateral margins. Dorsum of head bicolored, frons dark brown, clypeus and labrum orange-brown (Fig. 9D). Pronotum dark orange brown, slightly paler marginally. Elytra yellow-orange with serial dark brown spots. Head. Ground punctation on head fine. Clypeus with anteroposterior emargination which exposes a broadly rounded gap between clypeus and labrum (Fig. 9D). Mentum moderately depressed in anterior half with subtriangular anteromedial notch. Maxillary palps long, longer than width of head immediately posterior to eyes. Thorax. Ground punctation on pronotum fine. Prosternum slightly tectiform. Mesoventrite with weak elevation forming a posteromedial longitudinal carina. Metafemora densely pubescent in basal nine-tenths. Aedeagus. Aedeagus (Fig. 14B) with median lobe widest at base, appearing weakly constricted medially, slightly tapering until the apical quarter, then narrowing abruptly to form an acute triangular apex which is even with the apex of the parameres. Sclerite of the median lobe not expanded. Gonopore situated less than half of one gonopore width below the apex of the median lobe. Parameres symmetrical, with outer margins straight, with apex slightly inwardly curved and bluntly rounded. Basal piece long, ca. four-fifths the length of the parameres.

Etymology.

Named in honor of Venezuelan entomologist José (Pepe) Clavijo, retired director of MIZA, for all his contributions to Neotropical entomology. To be treated as a noun in apposition.

Distribution.

Known only from the San Nicolasito Research Station in the Llanos of Venezuela (Fig. 17).

Biology.

This species was collected along the margins of a morichal, a riparian habitat of slow-moving water through a savannah (Fig. 20B).

10.3897/zookeys.934.49359.figure15DEC4EAB8-D457-5756-B737-C921943747D2

Aedeagi of Chasmogenus spp. A–DC. pandusA dorsal view (Suriname) B side view (Suriname) C specimen from French Guiana D specimen from Brazil EC. ligulatusFC. sinnamarensisGC. undulatusH, IC. acuminatusH specimen from Suriname I specimen from Guyana. Scale bars: 0.25 mm.

https://binary.pensoft.net/fig/411770
10.3897/zookeys.934.49359.figure9AC0CB1D9-D01F-5E94-8289-DF066EC00BA2

Dorsal view of heads of Chasmogenus spp. AC. ampliusBC. acuminatusCC. berbicensisDC. clavijoiEC. undulatusFC. gato.

https://binary.pensoft.net/fig/411764
10.3897/zookeys.934.49359.figure17DC3C1004-D485-57B4-AF53-777636B24026

Distribution of Chasmogenus spp.

https://binary.pensoft.net/fig/411772
10.3897/zookeys.934.49359.figure205DAF7D61-C9A3-5F5C-BD36-D75F1A631DD9

Habitat of Chasmogenus spp. A Type locality and habitat for C. amplius and C. gato, Venezuela: Amazonas, Caño Gato (collecting event VZ09-0116-01X) B type locality and habitat for C. clavijoi, Venezuela: Guarico, San Nicolasito Field Station (collecting event VZ09-0110-02X) C–F habitat for C. australis: C Venezuela, Barinas, 13 km southeast of Ciudad Bolivia (collecting event VZ12-0125-02A) D Guyana, near Kusad Mountains (collecting event GY13-1027-01A). E, F Brazil, Roraima, near Caracarai, red circles showing live individuals of C. australis floating on the water surface (collecting event BR18-0116-05A).

https://binary.pensoft.net/fig/411775