Loading AI tools
Species of gastropod From Wikipedia, the free encyclopedia
Atlanta lesueurii is a species of sea snail, a holoplanktonic marine gastropod mollusk in the family Atlantidae.[3]
Atlanta lesueurii | |
---|---|
Apical view of the shell of Atlanta lesueurii from the Pliocene | |
Oblique apical view of the shell of Atlanta lesueurii | |
Scientific classification | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Mollusca |
Class: | Gastropoda |
Subclass: | Caenogastropoda |
Order: | Littorinimorpha |
Family: | Atlantidae |
Genus: | Atlanta |
Species: | A. lesueurii |
Binomial name | |
Atlanta lesueurii J. E. Gray, 1850[2] | |
Synonyms[3] | |
The maximal shell size of Atlanta lesueurii appears to vary geographically (from 2 mm in Hawaiian and eastern Australian waters to 6 mm in the tropical western Pacific).[5] The shell is transparent, thin and fragile, with a smooth surface (lacking raised sculpture). The spire is very small, somewhat elevated and compact, consisting of about 2½ whorls.[5] Spire sutures are deep, with the result that the whorls are somewhat rounded in profile and can easily be distinguished.[5] After metamorphosis the outermost whorl enlarges and inflates rapidly and the keel becomes progressively taller, becoming very tall in large adults and having a truncate leading edge.[5] The keel base and spire sutures are colorless.[5]
Main features for the recognition of this species are the protoconch composed of just 2¼-3 convex whorls, separated by an incised suture and the absence of any ornament.[1] The first teleoconch whorl expands rapidly and bears a well-developed flange-like keel.[1] In the largest specimens the final three quarters of the teleoconch separates from the penultimate whorl.[1]
Eyes are type b, with a large lens.[5] The Operculum is the type b.[5] Radula is type I, with a narrowly triangular shape.[5]
Atlanta lesueurii is the large species in the genus Atlanta, but Atlanta peronii is larger.
Atlanta lesueurii resembles closely Atlanta oligogyra, in which, however, the first whorls are separated by a superficial suture and the shell remains much smaller.[1]
Overview of description:
Atlanta lesueuri has a Recent circumglobal tropical/subtropical distribution.[1]
The first fossil specimens of Atlanta lesueurii has been found from Pliocene in Tiep, Roxas (map) and Anda, Pangasinan, Luzon, Philippines in 2001 (published in 2007).[1]
Vertical distribution in Hawaiian waters is restricted to upper 150 m, with most individuals in the upper 100 m and some evidence for nocturnal migration into the upper 50 m.[5]
Diel vertical distribution patterns of Atlanta lesueurii (among the 13 species of heteropods in the study) were investigated off leeward Oahu, Hawaii in waters overlying a bottom depth of 2,000 m (between 9 and 11 km off the coast) by Seapy (1990).[5] Heteropods were collected during day and night periods using paired, opening-closing BONGO nets at 50-m depth intervals between the surface and 200 m and at 200–300 m and 300–400 m.[5] Three or four replicated tows were taken in each depth interval.[5] Atlanta lesueurii was found to be the most abundant species, with a maximal density of 59 individuals per 1,000 m3 in a daytime 0–45 m depth interval.[5] The species ranged from the surface to 140 m during both day and night periods.[5] There was an apparent partial populational migration from a depth interval of 45–90 m during the day to 0–45 m at night.[5] However, high variability in densities between the replicated tows in each of the depth intervals resulted in statistically non-significant differences between day and night periods for each of the depth intervals.[5]
In a subsequent study off leeward Oahu (Seapy, 2008), duplicate tows were taken with a MOCNESS multiple, opening-closing net system during day and night periods at three stations located 1, 5 and 15 nm off the island in fall and spring sampling periods.[5] Mean densities were computed (as numbers of individuals beneath 100 m2 of ocean surface) during day and night periods at each station.[5] As in the 1990 study, Atlanta lesueurii was the most abundant species in the fall, although it was a close second to Atlanta plana in the spring.[5] Comparisons were made using the nighttime density data to avoid issues such as daytime net avoidance and to include increased nighttime abundances resulting from possible nocturnal vertical migrator species.[5] Atlanta lesueurii was found to be most abundant at the offshore (15 nm) station during both seasons.[5] Offshore to inshore abundance decreased most dramatically in the fall; from mean nighttime densities of 480 (15 nm) to 124 (5 nm) to 37 (1 nm) individuals beneath 100 m2 of ocean surface.[5] At the 15 nm station the species ranged downward to the greatest depths; to the 120–160 m depth interval in the spring and to the 80–120 m depth interval in the fall.[5] Clear evidence for nocturnal vertical migration was only seen in the spring at the 1-nm station (10-m depth interval tows were taken in the upper 100 m at this shallow-water station).[5] Highest abundances were recorded between 60 and 30 m during the day to 30 m to the surface at night.[5]
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.