Chasmogenus tafelbergensis, 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

publication ID

https://dx.doi.org/10.3897/zookeys.934.49359

publication LSID

lsid:zoobank.org:pub:B9F2C8D8-C031-4191-B6F5-1E78D4D6881E

persistent identifier

https://treatment.plazi.org/id/D3640B54-0826-4469-A091-AF1164BBEA14

taxon LSID

lsid:zoobank.org:act:D3640B54-0826-4469-A091-AF1164BBEA14

treatment provided by

ZooKeys by Pensoft

scientific name

Chasmogenus tafelbergensis
status

sp. nov.

Chasmogenus tafelbergensis sp. nov. Figures 16A-D View Figure 16 , 17 View Figure 17 , 21C View Figure 21

Type material.

Holotype (male). "Suriname: Sipaliwini District/ 3°55.600'N 56°11.300'W, 600m/ CSNR: Tafelberg Summit, nr/ Augustus Creek Camp, pools &/ creeks on trail into Arrowhead/ basin; leg. Short & Bloom. 17.viii.2013; SR13-0817-01A", "HOLOTYPE/ CHASMOGENUS/ tafelbergensis sp. n./ des. Smith & Short", "DNA VOUCHER/ Extraction #/ SLE-1825". (NZCS).

Differential diagnosis.

The strongly asymmetrical parameres, highly reduced basal piece, and extraordinary depth of the aedeagus (Fig. 16A-D View Figure 16 ) will easily separate this species from all others except C. ignotus , from which it may be differentiated by its narrower aedeagal profile. Examination of the aedeagus is the only way to definitively identify this species. Unassociated females may not be determined with certainty.

Description.

Size and color. Total body length 3.3 mm. Body form elongate oval with slightly curved lateral margins. Dorsum of head bicolored, frons dark red-brown, clypeus and labrum dark orange-brown. Pronotum and elytra uniformly dark brown. Head. Ground punctation on head moderately coarse. Clypeus with anteromedial emargination, which exposes angulate gap between clypeus and labrum. Mentum moderately depressed in anterior half with anteromedial subtriangular notch. Maxillary palps long, longer than width of head immediately posterior to eyes. Thorax. Ground punctation on pronotum moderately coarse. Prosternum mildly tectiform. Mesoventrite with very weak elevation forming a posteromedial longitudinal carina. Metafemora densely pubescent in basal six-sevenths. Aedeagus. Aedeagus (Fig. 16A-D View Figure 16 ) with median lobe highly modified, appearing as a narrow subparallel-sided strap and partly rotated laterally, with apex extending to the apex of the parameres. Sclerite of the median lobe extremely well developed and appearing as a thin curved strut that extends the full length of the genitalia. Gonopore oriented laterally (Fig. 15B View Figure 15 ); situated twice gonopore width below the apex of the median lobe. Parameres asymmetrical, with left paramere wider than right paramere; outer margins of parameres strongly sclerotized, with the sclerotized region on the right paramere thicker than the left. Aedeagus, especially the parameres, thickened, such that it takes on a highly three-dimensional appearance (Fig. 16B, C View Figure 16 ); in lateral view widest in basal half, with dorsal surface strongly convex, with ventral surface nearly flat. Basal piece short, less than half the length of the parameres; partly obscured by the strongly sclerotized and enlarged base of the median lobe and parameres.

Etymology.

Named after Tafelberg, a low elevation sandstone tepui in central Suriname. To be treated as a noun in apposition.

Distribution.

This species only known from the summit of Tafelberg Tepui in Suriname (Fig. 17 View Figure 17 ).

Biology.

The single specimen of this species was collected from forested pools which contained extremely dense layers of leaf litter detritus (Fig. 21C View Figure 21 ).

Kingdom

Animalia

Phylum

Arthropoda

Class

Insecta

Order

Coleoptera

Family

Hydrophilidae

Genus

Chasmogenus