Loading AI tools
Extinct genus of gastropods From Wikipedia, the free encyclopedia
Asthenotoma is a genus of sea snails, marine gastropod mollusks in the family Borsoniidae.[1]
| Asthenotoma | |
|---|---|
| |
| Shell of Asthenotoma lamothei | |
Scientific classification  | |
| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Mollusca |
| Class: | Gastropoda |
| Subclass: | Caenogastropoda |
| Order: | Neogastropoda |
| Superfamily: | Conoidea |
| Family: | Borsoniidae |
| Genus: | †Asthenotoma Harris & Burrows, 1891 |
| Type species | |
| †Pleurotoma meneghinii Mayer, 1868 | |
| Synonyms | |
|
† Oligotoma Bellardi, 1875 (Invalid: junior homonym of Oligotoma Westwood, 1836; Asthenotoma is a replacement name) | |
This genus, almost entirely represented by extinct species, is of slender form and elevated, evenly and gradually acuminate spire, conspicuous development of the spiral lyrae and short aperture. It should evidently be considered especially with Trypanotoma and allies, but it is somewhat of an annectant form, as the American species at least have true ribbing on the nepionic whorls which becomes completely lost on the larger volutions of the shell. It is therefore one of those puzzling exceptions which render an arrangement of the genera in a dichotomous table so difficult and unsatisfactory. The embryo in the type, Pleurotoma basteroti Desm., of the European Miocene, is said by Cossmann to be paucispiral, but the drawing shows a multispiral protoconch. This is, however, a matter of minor importance. The anal sinus is broad, sometimes very feeble and always median in position on the spire whorls though not identified with any particular one or more of the subequal and rather coarse flat spirals. The beak has no external oblique tumidity. There can be but little doubt, in view of geographical variations and wide distribution of this genus, that Endiatoma, of Cossmann, should be regarded as a synonym or as constituting a slightly differentiated section of Asthenotoma.[2]
Species within the genus Asthenotoma include:
Seamless Wikipedia browsing. On steroids.
Every time you click a link to Wikipedia, Wiktionary or Wikiquote in your browser's search results, it will show the modern Wikiwand interface.
Wikiwand extension is a five stars, simple, with minimum permission required to keep your browsing private, safe and transparent.
