Overview

Brief Summary

Introduction

Atlanta brunnea is a small species (shell diameter to 2.0 mm) that is darkly pigmented (brown to reddish-and golden-brown). The keel is tall and colorless, and inserts between the last and penultimate shell whorls in animals larger than 1.5 mm. The spire is tall and conical, consisting of 4 whorls and possessing a complex pattern of spiral sculpture that ends on the protoconch and is replaced by spiral rows of small punctae on the teleoconch. Coloration ranges from brown to amber and reddish-brown. Eyes type a, operculum type a, and radula type I. Geographic distribution is cosmopolitan in tropical to subtropical waters.

Diagnosis

  • Maximal shell diameter = 2.0 mm
  • Keel tall and colorless, and inserts between last and penultimate whorls in shells > 1.5 mm diameter
  • Spire tall and conical, with ornate, complex sculpture
  • Coloration brown to amber and reddish-brown
  • Eyes type a; operculum type a; radula type I

Trusted

Article rating from 0 people

Default rating: 2.5 of 5

Comprehensive Description

Characteristics

  1. Shell
    1. Small, with maximal shell diameter = 2.0 mm
    2. Keel tall and rounded
    3. Keel inserts between the last and penultimate shell whorls in shells larger than 1.5 mm

      Figure. Scanning electron micrographs of Atlanta brunnea shell. Left: right side, perpendicular to shell plane. Right: right side, tilted 60°. Scale bars = 0.5 mm. © Roger R. Seapy

    4. Spire (protoconch) of four whorls, with ornate and complex surface sculpture and a prominent spiral ridge on the outer margin of the whorls that progresses in height and begins on the second whorl (see enlarged views of the two images below)

    5. Spire sculpture replaced on teleoconch by spiral rows of small punctae (see enlarged view of second image below)

      Figure. High magnification scanning electron micrographs of shell spire in Atlanta brunnea. Left: view at right angle to shell plane. Right: view at 60º tilt. Scale bars = 0.1 mm. © Roger R. Seapy

    6. Shell and spire coloration light to dark brown, amber and reddish-brown (see title illustrations and below)

      Figure. Adult specimen of Atlanta brunnea to illustrate dark coloration. © Roger R. Seapy

  2. Eyes type a; lacking a transverse slit in the distal pigmented tissue
  3. Operculum type a (macro-oligogyre)
  4. Radula type I, small and ribbon shaped. Like Atlanta turriculata, each tooth row includes (1) a monocuspid central tooth, with a postero-lateral process on each side of the tooth, (2) biscuspid lateral teeth, each with a strong rectangular process on the inner side, and (3) a monocuspid marginal tooth
  5. Larva
    1. The two lobes of the velum in early larvae give rise to the six-lobed velum in late larvae

      Figure. Early (left) and late (right) stage larvae of Atlanta brunnea. Drawings combined from Franc (1948, Figs. 10, 11). © 1948 A. Franc

      Figure. Late veliger larva of Atlanta brunnea with six, ciliated velar lobes. Scale bar = 0.5 mm. Modified from Richter (1968, Fig. 11). © 1968 G. Richter

    2. Surface sculpture of larval shell (following the apical embryonic portion) of multiple, parallel spiral ridges

      Figure. Larval shell of Atlanta brunnea. Left: Scanning electron micrograph of shell viewed in the shell plane. Scale bar = 50 µm. Modified from Thiriot-Quiévreux (1973, Fig. 6b). © 1973 C. Thiriot Right: Sketches of three stages in the development of the larval shell. Scale bar = 250 µm. Modified from Richter (1968, Fig. 10). © 1968 G. Richter

Comments:

Atlanta brunnea is a cosmopolitan species, found at tropical to subtropical latitudes. It is limited to the upper 100 m of the water column in Hawaiian waters (Seapy, 1990b). Comparison of day and night vertical distribution of abundances suggested that a portion of the population from 50-100 m migrated into the upper 50 m at night

Trusted

Article rating from 0 people

Default rating: 2.5 of 5

Ecology

Habitat

Depth range based on 39 specimens in 1 taxon.
Water temperature and chemistry ranges based on 27 samples.

Environmental ranges
  Depth range (m): 37.5 - 4766
  Temperature range (°C): 5.743 - 21.004
  Nitrate (umol/L): 0.316 - 18.078
  Salinity (PPS): 35.232 - 38.778
  Oxygen (ml/l): 3.565 - 5.477
  Phosphate (umol/l): 0.092 - 1.129
  Silicate (umol/l): 0.754 - 12.706

Graphical representation

Depth range (m): 37.5 - 4766

Temperature range (°C): 5.743 - 21.004

Nitrate (umol/L): 0.316 - 18.078

Salinity (PPS): 35.232 - 38.778

Oxygen (ml/l): 3.565 - 5.477

Phosphate (umol/l): 0.092 - 1.129

Silicate (umol/l): 0.754 - 12.706
 
Note: this information has not been validated. Check this *note*. Your feedback is most welcome.

Trusted

Article rating from 0 people

Default rating: 2.5 of 5

Wikipedia

Atlanta brunnea

Atlanta brunnea is a species of sea snail, a holoplanktonic marine gastropod mollusk in the family Atlantidae.[4]

Contents

Description

Atlanta brunnea is a small species (shell diameter to 2.0 mm) that is darkly pigmented (brown to reddish-and golden-brown).[5] The keel is tall and colorless, and inserts between the last and penultimate shell whorls in animals larger than 1.5 mm.[5] The spire is tall and conical, consisting of 4 whorls and possessing a complex pattern of spiral sculpture that ends on the protoconch and is replaced by spiral rows of small punctae on the teleoconch.[5] Coloration ranges from brown to amber and reddish-brown.[5]

lateral view of the protoconch of Atlanta brunnea

Juveniles of this species are easily recognised by their shape and ornament.[1] The protoconch is rather high conical and has 3½ - 3¾ whorls, slowly increasing in diameter.[1] On the first whorl, in front of the nucleus, an ornament is seen of some nine or ten irregular spirals.[1] Two stronger spirals from the second whorl on delimit a subsutural zone and the base of the shell.[1] On these spirals the whorl profile is slightly angular.[1] The whole surface of the protoconch is furthermore covered with numerous finer spirals in an irregular zigzag shape, also on the base and within the umbilicus.[1] The boundary with the teleoconch is made distinct by the sudden disappearance of these spirals.[1] From that point on the whorl diameter increases rapidly, by which the shape of the shell becomes lenticular.[1] Somewhat more than one teleoconch whorl is present in the largest specimens.[1] The periphery of the body whorl is angular and bears a distinct flange-like keel.[1] The protoconch is visible in an apertural view.[1]

Eyes aretype a, operculum is type a, and radula type I.[5]

Description overview:

  • The maximum recorded shell length is 1.7 mm.[6] / Maximal shell diameter is 2.0 mm.[5]
  • Keel tall and colorless, and inserts between last and penultimate whorls in shells > 1.5 mm diameter[5]
  • Spire tall and conical, with ornate, complex sculpture[5]
  • Coloration brown to amber and reddish-brown[5]
  • Eyes type a; operculum type a; radula type I[5]

Distribution

Atlanta brunnea has an almost worldwide tropical and subtropical distribution pattern.[1]

Fossil distribution

Atlanta brunnea is known from the Pliocene of Anda, Pangasinan, Luzon, Philippines.[1]

Ecology

It is limited to the upper 100 m of the water column in Hawaiian waters.[5] Comparison of day and night vertical distribution of abundances suggested that a portion of the population from 50–100 m migrated into the upper 50 m at night.[5]

References

This article incorporates CC-BY-3.0 text from references.[1][5]

  1. ^ a b c d e f g h i j k l m n o Janssen A. W. (2007). "Holoplanktonic Mollusca (Gastropoda: Pterotracheoidea, Janthinoidea, Thecosomata and Gymnosomata) from the Pliocene of Pangasinan (Luzon, Philippines)". Scripta Geologica 135. http://www.scriptageologica.nl/07/nr135/a02.
  2. ^ Gray J. E. (1850). Catalogue of the Mollusca in the collection of the British Museum, 2. Pteropoda. British Museum and E. Newman, London: iv + 45 pp.
  3. ^ (French) Souleyet F. L. A. (1852). In: Eydoux, [F.] & Souleyet, [F.L.A.] Voyage autour du monde exécuté pendant les années 1836 et 1837 sur la corvette ‘La Bonite’, commandée par M. Vaillant, capitaine de vaisseau, publié par ordre du Gouvernement sous les auspices du département de la marine. Zoologie, 2. Mollusques; Ptéropodes: 37-392, atlas (undated): pls 4-15, 15bis, 16-23, 23bis, 24, 24bis. A. Bertrand, Paris.
  4. ^ a b Atlanta brunnea J. E. Gray, 1850. WoRMS (2010). Atlanta brunnea J. E. Gray, 1850. In: Bouchet, P.; Gofas, S.; Rosenberg, G. (2010) World Marine Mollusca database. Accessed through: World Register of Marine Species at http://www.marinespecies.org/aphia.php?p=taxdetails&id=238118 on 14 August 2010.
  5. ^ a b c d e f g h i j k l m Seapy R. R. (2009). Atlanta brunnea Gray 1850. Atlanta fusca Souleyet 1852. Version 03 September 2009. http://tolweb.org/Atlanta_brunnea/28759/2009.09.03 in The Tree of Life Web Project.
  6. ^ Welch J. J. (2010). "The "Island Rule" and Deep-Sea Gastropods: Re-Examining the Evidence". PLoS ONE 5(1): e8776. doi:10.1371/journal.pone.0008776.
Creative Commons Attribution Share Alike 3.0 (CC BY-SA 3.0)

Source: Wikipedia

Unreviewed

Article rating from 0 people

Default rating: 2.5 of 5

Disclaimer

EOL content is automatically assembled from many different content providers. As a result, from time to time you may find pages on EOL that are confusing.

To request an improvement, please leave a comment on the page. Thank you!