Chasmogenus clavijoi, Smith & Short, 2020

Smith, Rachel R. & Short, Andrew Edward Z., 2020, Review of the genus Chasmogenus Sharp, 1882 of northeastern South America with an emphasis on Venezuela, Suriname, and Guyana (Coleoptera, Hydrophilidae, Acidocerinae), ZooKeys 934, pp. 25-79 : 25

Chasmogenus clavijoi sp. nov. Figures 9D , 14B , 17 , 20B

Material examined.

Holotype (male): "Venezuela: Guárico Stat e / 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).

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 ).

Figures

Figure 9. Dorsal view of heads of Chasmogenus spp. A C. amplius B C. acuminatus C C. berbicensis D C. clavijoi E C. undulatus F C. gato.

Figure 14. Aedeagi of (dorsal view) of Chasmogenus spp. A C. amplius B C. clavijoi C C. gato D C. berbicensis E C. brownsbergensis F C. schmits G, H C. guianensis G specimen from Suriname H specimen from Guyana. Scale bar: 0.25 mm.

Figure 17. Distribution of Chasmogenus spp.

Figure 20. Habitat of Chasmogenus spp. A Type locality and habitat for C. amplius and C. gato, Venezuela: Amazonas, Cano Gato (collecting event VZ 09 - 0116 - 01 X) B type locality and habitat for C. clavijoi, Venezuela: Guarico, San Nicolasito Field Station (collecting event VZ 09 - 0110 - 02 X) C-F habitat for C. australis: C Venezuela, Barinas, 13 km southeast of Ciudad Bolivia (collecting event VZ 12 - 0125 - 02 A) D Guyana, near Kusad Mountains (collecting event GY 13 - 1027 - 01 A). E, F Brazil, Roraima, near Caracarai, red circles showing live individuals of C. australis floating on the water surface (collecting event BR 18 - 0116 - 05 A).