Chasmogenus Sharp, 1882

Glynn, Rachel D. & Short, Andrew Edward Z., 2021, New species and records of Chasmogenus Sharp, 1882 from the southwestern margin of the Guiana Shield (Coleoptera: Hydrophilidae: Acidocerinae), Zootaxa 5048 (3), pp. 435-443 : 442-443

publication ID

https://doi.org/ 10.11646/zootaxa.5048.3.8

publication LSID

lsid:zoobank.org:pub:B1B24583-1DFC-49BA-BDF7-A48F3D74E7E2

DOI

https://doi.org/10.5281/zenodo.5569566

persistent identifier

https://treatment.plazi.org/id/03B487A0-7F14-FFCF-FF30-16D56EFBA669

treatment provided by

Plazi

scientific name

Chasmogenus Sharp
status

 

Key to the species of Chasmogenus Sharp View in CoL of Venezuela, Suriname, Guyana, French Guiana, and Brazil north of the Amazon River

We have modified the key presented in Smith & Short (2020) to insert the three species described here. All three species would key to couplet 13 in the original key, so we have not repeated those here. We emphasize that examination of the genitalia is crucial to accurate identifications and unassociated females of the three species described here cannot be identified with precision.

13 Aedeagus with apex of median lobe long, distinctly extending beyond the apex of the parameres; basal piece short, one-third the total length of the parameres or less (e.g. Smith & Short 2020: fig. 15A–E, 15G–I)............................. 14

- Aedeagus with apex of median lobe shorter or not extending beyond the apex of the parameres; basal piece long, up to one-half the length of the entire aedeagus........................................................................ 17

14 Parameres of aedeagus smooth along outer edges, not sinuate or undulate, apex of median lobe acuminates at the apex ( Smith & Short 2020: fig. 15H, I); gonopore situated toward the apex of the median lobe............ C. acuminatus Smith & Short View in CoL

- Parameres moderately sinuate along outer margins; gonopore situated about in the middle of the median lobe............15

15 Median lobe of aedeagus terminating in a broadly rounded apex past the apex of the parameres (e.g. Smith & Short 2020: fig. 15E);.......................................................................... C. ligulatus Smith & Short View in CoL

- Median lobe narrowing to a moderately to acutely pointed apex past the apex of the parameres...................... 16a

16a Median lobe with apex acuminate (e.g. Smith & Short 2020: fig. 15A–D); emargination of the clypeus narrow (e.g. Smith & Short 2020: figs 5D–F, 10D).......................................................................... 16b

- Median lobe with apex rounded ( Smith & Short 2020: fig. 15G); dorsal coloration dark brown, emargination of the clypeus rounded to angulate............................................................. C. undulatus Smith & Short View in CoL

16b Outer margins of parameres with two constrictions (bisinuate) (e.g. Smith and Short 2020: fig. 15A–D); dorsal coloration dark reddish brown and translucent (e.g. Smith and Short 2020: figs. 5D–F, 10D)................... C. pandus Smith & Short View in CoL

- Outer margins of parameres with a single constriction (sinuate) (fig. 4A–D); dorsal coloration uniformly dark brown (fig. 2A, B).................................................................................... C. clinatus View in CoL sp. n.

17 Median lobe of aedeagus shorter than length of parameres, aedeagus symmetrical................................. 18

- Apex of median lobe of aedeagus approximately even with apex of parameres.................................... 19

18 Apex of parameres bluntly squared ( Smith & Short 2020: fig. 14F).......................... C. schmits Smith & Short View in CoL

- Apex of parameres rounded ( Smith & Short 2020: fig. 14G, H).......................... C. guianensis Smith & Short View in CoL

19 Distinct dark patches on mesal portion of clypeus and labrum ( Smith & Short 2020: fig.10A).................................................................................................. C. brownsbergensis Smith & Short View in CoL

- Clypeus and labrum without distinct dark patches........................................................... 20

20 Aedeagus with parameres straight along outer margins, only curving inward past the position of the gonopore........... 21

- Aedeagus with parameres that curve slightly inward along the outer margins throughout the entire length (figs. 5A, B)............................................................................................... C. inpa View in CoL sp. n.

21 Apex of median lobe rounded triangular in shape (figs. 5C, D).................................... C. gironae View in CoL sp. n.

- Apex of median lobe acutely triangular in shape............................................................ 22

22 Total body size ≤ 3.8 mm, dorsal coloration very dark brown................................. .. C. gato Smith & Short View in CoL

- Total body length ≥ 3.8 mm, dorsal coloration pale orange-brown..................... C. clavijoi Smith & Short View in CoL (in part)

Kingdom

Animalia

Phylum

Arthropoda

Class

Insecta

Order

Coleoptera

Family

Hydrophilidae

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