Coelostoma Brulle 1835
- Dataset
- Review of Coelostoma of the Indian subcontinent (Coleoptera: Hydrophilidae) Part 1: Coelostoma s. str. and Holocoelostoma
- Rank
- GENUS
Classification
- kingdom
- Animalia
- phylum
- Arthropoda
- class
- Insecta
- order
- Coleoptera
- family
- Hydrophilidae
- genus
- Coelostoma
description
Mouchamps (1958) defined four subgenera of Coelostoma on the basis of the combination of three characters: (1) the pubescence on the mesofemora (with or without dense pubescence), (2) morphology of the abdominal apex (with or without stout setae) and (3) the morphology of the tarsal claws (simple or bifid, the latter in the subgenus Hammacoelostoma Mouchamps, 1958, not occurring in the Indian subcontinent). These characters have since then been successfully used to place all described species in subgenera (e. g., Hansen 1999). Characters (1) and (2), relevant for recognizing the subgenera occurring in India, were illustrated by Jia et al. (2014). The study of the Indian Coelostoma revealed that the morphological diversity within the genus is much higher than expected, especially in the subgenus Lachnocoelostoma, with some species not fitting the combination of characters used by Mouchamps (1958). To deal with this problem, we are adapting the definition of the subgenera of Coelostoma in the way specified in Table 1, using five characters. The re-examination of C. (Hammacoelostoma) afflatum Knisch, 1922 revealed that the additional strongly sclerotized projections between the tarsal claws are in fact modified empodial setae, and not basal projections of the claws as suggested by Mouchamps (1958). Our concept narrows down the definition of Coelostoma s. str. and significantly widens the concept of Lachnocoelostoma. Reasons for that will be demonstrated in detail in the review of Indian Lachnocoelostoma (Sheth et al., in prep.). The atypical species of Lachnocoelostoma (i. e., those having largely bare mesofemora or abdominal apex without stout setae) always differ from the subgenera treated in this paper in the presence of the abdominal median carina. The carina is absent in all Coelostoma s. str. and in all Holocoelostoma, including all species treated in this paper.
Name
- Homonyms
- Coelostoma Brulle 1835