Published December 31, 2015 | Version v1
Taxonomic treatment Open

Axinulus croulinensis Jeffreys 1847

Description

Axinulus aff. croulinensis Jeffreys, 1847

Fig. 4A

Material. Two specimens, Off Ras Madrakah, southern Oman, Discovery cruise 211 st. 12719#1, 19°08´N 58°39´E, 3150 m, collected P.G. Oliver, 31 October 1994. NMW.Z. 1995.009.18.

Description. To 2 mm in height. Very thin shelled. Equivalve. Equilateral. Outline almost circular a little higher than long; anterior dorsal margin very short, horizontal; anterior curved, ventral slightly extended, posterior curved; posterior dorsal short sloping gently. Hinge plate smooth, edentulous.

Remarks. In every respect these shells are identical with A. croulinensis from the Atlantic Ocean (Fig. 4 B). In the Atlantic A. croulinensis has been recorded throughout and from depths a little as 40 m to 3861 m (Payne & Allen 1991). Zelaya (2010) separated off the Antarctic populations as A. antarcticus Zelaya, 2010 but from shell characters there is little difference. The Atlantic abyssal A. brevis (Fig. 4 E) has a more tear-drop shaped shell with a distinct anterior slope while an undescribed species (Fig. 4 C) from the Gulf of Mexico is distinctly oblique. Other species cited in WoRMS under Axinulus do not conform and need reassignment or placed in as yet undescribed genera. The genus Genaxinus is distinct with the very characteristic elevated adductor scars with species known from the Atlantic and SE Australia; Genaxinus eumyarius M. Sars, 1870 and Genaxinus albigena Hedley, 1907. Axinulus careyi Bernard, 1979 has the appearance of a Mendicula and Axinulus hadalis (Okutani, Fujikura & Kojima, 1999) and Axinulus thackergeigeri Valentich-Scott & Coan, 2012 in Coan & Valentich-Scott, 2012 require novel placement.

Notes

Published as part of Oliver, P. Graham, 2015, Deep-water Thyasiridae (Mollusca: Bivalvia) from the Oman Margin, Arabian Sea, new species and examples of endemism and cosmopolitanism, pp. 252-263 in Zootaxa 3995 (1) on page 259, DOI: 10.11646/zootaxa.3995.1.21, http://zenodo.org/record/236857

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Linked records

Additional details

Biodiversity

Family
Thyasiridae
Genus
Axinulus
Kingdom
Animalia
Order
Lucinoida
Phylum
Mollusca
Scientific name authorship
Jeffreys
Species
croulinensis
Taxon rank
species
Taxonomic concept label
Axinulus croulinensis Jeffreys, 1847 sec. Oliver, 2015

References

  • Jeffreys, J. G. (1847) Additional notices on British shells. Annals and magazine of Natural History, 20, 16 - 19. http: // dx. doi. org / 10.1080 / 037454809496005
  • Payne, C. M. & Allen, J. A. (1991) The morphology of deep-sea Thyasiridae (Mollusca: Bivalvia) from the Atlantic Ocean. Philosophical Transactions of the Royal Society of London Series B, 334, 481 - 566. http: // dx. doi. org / 10.1098 / rstb. 1991.0128
  • Zelaya, D. G. (2010) New species of Thyasira, Mendicula, and Axinulus (Bivalvia, Thyasiroidea) from Sub-Antarctic and Antarctic waters. Polar Biology, 33, 607 - 616.
  • Sars, M. (1870) Bidrag til Kundskab om Christiania-fjordens Fauna. Efter Forfatterens efterladte Manuskripter samlet og udgivet af hans Son. Johan Dahlk, Vol. II, 1 - 145.
  • Hedley, C. (1907) The results of the deep sea investigations in the Tasman Sea II. The expedition of the '' Woy Woy' '. Records of the Australian Museum, 6, 356 - 364. http: // dx. doi. org / 10.3853 / j. 0067 - 1975.6.1907.1020
  • Okutani, O., Fujikura, K. & Kojima, S. (1999) Two new hadal bivalves of the Family Thyasiridae from the convergent area of the Japan Trench. Venus, 58 (2), 49 - 59.
  • Coan, E. V. & Valentich-Scott, P. (2012) Bivalve Seashells of Tropical West America. Marine Bivalve Mollusks from Baja California to Northern Peru. Santa Barbara Museum of Natural History Monographs Number 6, Part 1, pp. 1 - 596.