Chasmogenus

Superregnum: Eukaryota
Cladus: Unikonta
Cladus: Opisthokonta
Cladus: Holozoa
Regnum: Animalia
Subregnum: Eumetazoa
Cladus: Bilateria
Cladus: Nephrozoa
Cladus: Protostomia
Cladus: Ecdysozoa
Cladus: Panarthropoda
Phylum: Arthropoda
Subphylum: Hexapoda
Classis: Insecta
Cladus: Dicondylia
Subclassis: Pterygota
Cladus: Metapterygota
Infraclassis: Neoptera
Cladus: Eumetabola
Cladus: Endopterygota
Superordo: Coleopterida
Ordo: Coleoptera
Subordo: Polyphaga
Infraordo: Staphyliniformia
Superfamilia: Hydrophiloidea

Familia: Hydrophilidae
Subfamilia: Acidocerinae
Genus: Chasmogenus
Subgenera (2): C. (Chasmogenus) – C. (Crephelochares)
Overview of species (55)

C. abnormalis – C. acuminatus – C. africanus – C. amplius – C. australis – C. balkei – C. bariorum – C. barrae – C. berbicensis – C. brownsbergensis – C. castaneus – C. cattienus – C. clavijoi – C. cuspifer – C. flavomarginatus – C. fragilis – C. gato – C. guianensis – C. ignotus – C. irianus – C. ligulatus – C. lineatus – C. livornicus – C. lorenzo – C. luctuosus – C. lycetus – C. mauritiensis – C. molinai – C. mollis – C. molluscus – C. nitescens – C. occidentalis – C. omissus – C. orbus – C. paramollis – C. parorbus – C. patrizii – C. punctulatus – C. pandus – C. ruandanus – C. rubellus – C. rubricollis – C. rudis – C. rufinasus – C. ruidus – C. rusticus – C. rutiloides – C. rutilus – C. sapucay – C. schmits – C. schoedli – C. sinnamarensis – C. szeli – C. tafelbergensis – C. undulatus – C. yukparum

Add (4): C. fluminensis – C. itatiaia – C. lilianae – C. ubatuba
Name

Chasmogenus Sharp, 1882

References

Sharp, D. 1882. On some New Zealand Coleoptera. Transactions of the Entomological Society of London 1882 [30(1)]: 73–99. DOI: 10.1111/j.1365-2311.1882.tb01570.x Paywall. BHL. Reference page.
García, M. 2000: [Four new species of Chasmogenus Sharp, 1882 (Coleoptera: Hydrophilidae: Hydrophilinae) from Venezuela.] Boletín del Centro de Investigaciones Biológicas Universidad del Zulia, 34(1): 45–58. [in Spanish] PDF
Hansen, M. 1991: The hydrophilid beetles: phylogeny, classification and a revision of the genera (Coleoptera, Hydrophiloidea). Biologiske skrifter, 40 ISSN: 0366-3612 ISBN 87-7304-226-9 Google books
Hebauer, F. 1992: The Species of the Genus Chasmogenus Sharp, 1882 (Coleoptera, Hydrophilidae). Acta coleopterologica, 8(2): 61–92. PDF
Hebauer, F. 1995: The hydrophilid and spercheid beetles of Namibia in consideration of the material of the Namibia Expedition of the Museum of Natural History Berlin in 1992, supplement by results of former Namibia and Kalahari Expeditions (Coleoptera, Hydrophiloidea: Hydrophilidae et Spercheidae). Mitteilungen aus dem Zoologischen Museum in Berlin, 71(2): 251–275. DOI: 10.1002/mmnz.19950710206 [not seen]
Hebauer, F. 2001: Beitrag zur Kenntnis der Hydrophilidae von Neuguinea. Ergebnisse der zoologischen Forschungsreisen von M. Balke und L. Hendrich nach West Neuguinea (Irian Jaya) in den Jahren 1990–1998. (Coleoptera: Hydrophilidae). Acta coleopterologica, 17(1): 3–72. [not seen]
Hebauer, F. 2002: New Hydrophilidae of the Old World (Coleoptera: Hydrophilidae). Acta coleopterologica, 18(3): 3–24. [not seen]
Jia, F-L. & Tang, Y-D. 2018. A faunistic study of genus Chasmogenus Sharp, 1882 of China (Coleoptera, Hydrophilidae). ZooKeys 738: 59–66. DOI: 10.3897/zookeys.738.21711. Reference page.
Short, A.E.Z. 2005: A review of the subtribe Acidocerina of Central America with special reference to Costa Rica (Coleoptera: Hydrophilidae). Koleopterologische rundschau, 75: 191–226. PDF
Short, A.E.Z. 2010: Hydrophilidae: Review of the subtribe Acidocerina of the Southwest Pacific islands (Coleoptera). Pp. 297-318 in: Jäch, M.A. & Balke, M. (eds.): Water beetles of New Caledonia (part 1). Monographs on Coleoptera, 3. ISSN: 1027-8869
Short, A.E.Z.; Hebauer, F. 2006: World Catalogue of Hydrophiloidea – additions and corrections, 1 (1999–2005) (Coleoptera). Koleopterologische rundschau, 76: 315–359. PDF
Smith, R.R. & Short, A.E.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: 25–79. DOI: 10.3897/zookeys.934.49359 Open access Reference page.
Watts, C.H.S. 1995: Revision of the Australasian genera Agraphydrus Regimbart, Chasmogenus Sharp and Helochares Mulsant (Coleoptera: Hydrophilidae). Records of the South Australian Museum 28(1): 113-130. Reference page.

Additional references

Devi, M.B., Devi, O.S., Fikáček, M., Minoshima, Y.N. & Wanghengbam, L. 2016. Redescription and lectotype designation of Chasmogenus abnormalis (Sharp), with notes on its distribution. Zootaxa 4144(2): 296–300. DOI: 10.11646/zootaxa.4144.2.12. Reference page.

Chasmogenus is a Neotropical genus of water scavenger beetles belonging to the family Hydrophilidae.[1]

Taxonomy

The genus Chasmogenus was described for the first time by David Sharp in 1882 for species from Guatemala and Panama.[2]

Since 1919 the genus Crephelochares (from the Old World) was considered a synonym of Chasmogenus,[3] but thanks to the results of a phylogenetic analysis involving molecular data,[4] both taxa are now considered distinct genera on their own right.[1]

Currently, a total of 36 species is identified and documented, most of them recorded from the Guiana Shield Region.
Description

Small size (2.5–5.0 mm), bearing a clearly visible sutural stria; long maxillary palps; metafemora usually densely covered by hydrofuge pubescence. The external morphology in Chasmogenus is very uniform across species, so that most species can only be identified by the shape of the male genitalia.

By the presence of the sutural stria, in the Neotropical region, Chasmogenus can only be confused with some members of the genus Primocerus.[1]
Habitat

According to Girón and Short:[1]

The vast majority of Chasmogenus are known from forested habitats, including the margins of streams and forest pools. A few species are known from open marsh habitats (e.g., Chasmogenus australis García and Chasmogenus sapucay Fernández). They can be found among the vegetation and submerged leaf litter. They are also attracted to lights, though usually not in large numbers. Only one species [Chasmogenus cremobates (Spangler)] has been collected in seepages.
— Girón and Short, The Acidocerinae (Coleoptera, Hydrophilidae): taxonomy, classification, and catalog of species

Species

Chasmogenus acuminatus Smith and Short, 2020 [5]
Chasmogenus amplius Smith and Short, 2020 [5]
Chasmogenus australis García, 2000 [6]
Chasmogenus bariorum García, 2000 [6]
Chasmogenus barrae Short, 2005 [7]
Chasmogenus berbicensis Smith and Short, 2020 [5]
Chasmogenus brownsbergensis Smith and Short, 2020 [5]
Chasmogenus cajuina Alves, Clarkson and Lima, 2020 [8]
Chasmogenus castaneus Smith and Short, 2020 [5]
Chasmogenus clavijoi Smith and Short, 2020 [5]
Chasmogenus clinatus Glynn and Short, 2021 [9]
Chasmogenus cremnobates (Spangler, 1979) [10]
Chasmogenus cuspifer Smith and Short, 2020 [5]
Chasmogenus flavomarginatus Smith and Short, 2020 [5]
Chasmogenus fluminensis Clarkson and Ferreira-Jr, 2014 [8]
Chasmogenus fragilis Sharp, 1882 [2]
Chasmogenus gato Smith and Short, 2020 [5]
Chasmogenus gironae Glynn and Short, 2021 [9]
Chasmogenus guianensis Smith and Short, 2020 [5]
Chasmogenus ignotus Smith and Short, 2020 [5]
Chasmogenus inpa Glynn and Short, 2021 [9]
Chasmogenus itatiaia Clarkson and Ferreira-Jr, 2014 [8]
Chasmogenus ligulatus Smith and Short, 2020 [5]
Chasmogenus lilianae Clarkson and Ferreira-Jr, 2014 [8]
Chasmogenus lineatus Smith and Short, 2020 [5]
Chasmogenus lorenzo Short, 2005 [7]
Chasmogenus pandus Smith and Short, 2020 [5]
Chasmogenus rufinasus (Knisch, 1924) [11]
Chasmogenus ruidus Short, 2005 [7]
Chasmogenus sapucay Fernández, 1986 [12]
Chasmogenus schmits Smith and Short, 2020 [5]
Chasmogenus schoedli Short, 2005 [7]
Chasmogenus sinnamarensis Smith and Short, 2020 [5]
Chasmogenus tafelbergensis Smith and Short, 2020 [5]
Chasmogenus ubatuba Clarkson and Ferreira-Jr, 2014 [8]
Chasmogenus undulatus Smith and Short, 2020 [5]

References

Girón, JC; Short, AEZ (18 June 2021). "The Acidocerinae (Coleoptera, Hydrophilidae): taxonomy, classification, and catalog of species". ZooKeys (1045): 1–236. doi:10.3897/zookeys.1045.63810. PMC 8233300. PMID 34228772.
Sharp, D. (1882). Fam. Hydrophilidae. In: Biologia Centrali-Americana Insecta. Coleoptera. Volume 1. Part 2. Vol. 1. pp. 53–80.
d’Orchymont, A. (1919). "Contribution à l'étude des sous-familles des Sphaeridiinae et des Hydrophilinae (Col. Hydrophilidae)". Annales de la Société entomologique de France. 88 (1–2): 105–168.
Short, Andrew Edward Z.; Girón, Jennifer C.; Toussaint, Emmanuel F. A. (2021). "Evolution and biogeography of acidocerine water scavenger beetles (Coleoptera: Hydrophilidae) shaped by Gondwanan vicariance and Cenozoic isolation of South America". Systematic Entomology. 46 (2): 380–395. doi:10.1111/syen.12467. ISSN 1365-3113. S2CID 232264478.
Smith, Rachel R.; Short, Andrew Edward Z. (2020-05-19). "Review of the genus Chasmogenus Sharp, 1882 of northeastern South America with an emphasis on Venezuela, Suriname, and Guyana (Coleoptera, Hydrophilidae, Acidocerinae)". ZooKeys (934): 25–79. doi:10.3897/zookeys.934.49359. ISSN 1313-2970. PMC 7250940. PMID 32508494.
García, M. (2000). "Four new species of Chasmogenus Sharp, 1882 (Coleoptera: Hydrophilidae: Hydrophilinae) from Venezuela". Boletín del Centro de Investigaciones Biológicas Universidad del Zulia. 34: 45–58.
Short, A. E. Z. (2005). "A review of the subtribe Acidocerina of Central America with special reference to Costa Rica (Coleoptera: Hydrophilidae)" (PDF). Koleopterologische Rundschau. 75: 191–226.
Clarkson, B; Ferreira Jr, N (2014). "Four new species and first nominal record of Chasmogenus Sharp, 1882 (Coleoptera: Hydrophilidae) from Brazil" (PDF). Zootaxa. 3765 (5): 481–494. doi:10.11646/zootaxa.3765.5.6. PMID 24870916. S2CID 46379711. Archived from the original on 2019-03-07.
Glynn, Rachel D.; Short, Andrew Edward Z. (2021-10-07). "New species and records of Chasmogenus Sharp, 1882 from the southwestern margin of the Guiana Shield (Coleoptera: Hydrophilidae: Acidocerinae)". Zootaxa. 5048 (3): 435–443. doi:10.11646/zootaxa.5048.3.8. ISSN 1175-5334. PMID 34810791. S2CID 242935735.
Spangler, P. J. (1979). "A new genus of madicolous beetles from Ecuador (Coleoptera: Hydrophilidae: Hydrobiinae)". Proceedings of the Biological Society of Washington. 92: 753–761.
Knisch, A. (1924). "Neue neotropische Palpicornier. (Col. Hydrophilidae. - Op. 16.)". Wiener Entomologische Zeitung. 41: 114–140.
Fernández, L. A. (1986). "Consideraciones sobre el género Chasmogenus Sharp y descripción de Chasmogenus sapucay sp. nov. (Coleoptera: Hydrophilidae)". Neotrópica. 32: 189–193.