Stenosemus exaratus
Creators
Description
Stenosemus exaratus (G.O. Sars, 1878)
(Figures 23A, B 24–26)
Lophyrus exaratus G.O. Sars, 1878: 113, pl. 8, fig. 1, pl. II, fig. 1.
Lepidopleurus dorsuosus Haddon, 1886: 18, pl. 1, fig. 5, pl. 3, figs. 5a–i.
Lepidopleurus dallii Haddon, 1886: 19, pl. 1, fig. 6, pl. 3, figs. 6a–i.
Ischnochiton (Chondropleura) affinis Thiele, 1906, 334, pl. 29, figs. 17–20.
Lepidopleurus (Leptochiton) nicomedes Dall, 1919: 501.
Ischnochiton johnstoni Cotton, 1937: 11, figs. 10–18.
Lepidopleurus nicomedes; Leloup, 1956: 15 (bibliography).
Ischnochiton exaratus; Leloup, 1956: 41, fig. 21; Kaas, 1972: 92, figs. 195–199, pl. 6, fig. 9.
Ischnochiton dorsuosus; Dell, 1964: 114 (bibliography); Kaas, 1979: 29; Ferreira, 1980: 59.
Ischnochiton (Stenosemus) exaratus; Kaas, 1979: 29; Kaas & Van Belle 1990: 62, fig. 25. maps 1, 23 (synonymy and bibliography).
Stenosemus exaratus; Ferreira, 1981: 327.
Type material. Two syntypes (NHMO D33573). Type locality. Norway, Bodö (67°17’N, 14°25’E) and Florö (61°36’N, 5°0’E), 180–360 m.
Material examined. Southern Ocean, Macquarie Islands, R/V Dmitry Mendeleev, cruise 16, stn 1294, 54°56.5’S, 158°49.7’E, 320 m, Sigsby trawl, 4 spms, BL 11.0–14.0 mm, 25.01.1976; Macquarie Islands, offshore to W, 54.7119°S, 158.7679°E, 200–468 m, stn SS1999_01_060Lot_60, Benthic dredge, CSIRO, 1 spm (TMAG, E 45537) BL 16.0 mm, 22.01.1999. Macquarie Islands, offshore to E, 54.5959°S, 158.9433°E, 250–500 m, stn SS1999_093Lot_093, Benthic dredge, CSIRO, 28 spm (TMAG, E 45535) BL 10.5–17.0 mm, 26.01.1999; Southern Tasmania Slope: Southern Sirveyor, 44.0306°S, 147.5796°E, 830–1030 m, stn SS0207_08_Lot_8, Sherman sled, CSIRO, 2 spm (TMAG, E 45526) BL 11.0–12.0 mm, 31.03.2007.
Distribution. Wide-spread species. It inhabits the Atlantic Ocean from Greenland, Iceland, Norway up to Terra del Fuego, South Shetlands and South Orkney Islands, Pacific Ocean near Southern Chile, Indian Ocean near Prince Edward, Kerguelen and Amsterdam Islands. The four above mentioned samples of this species are the first find for South Australia and Macquarie Islands. The species lives at depths from 23 up to 2580 m (Kaas & Van Belle 1990; Schwabe & Sellanes 2010).
Remarks. The specimen (TMAG, E 45526, BL 11.5 mm) studied under SEM has 21 gills on each side arranged from valve IV to the anus; radula 4.1 mm long with 31 transverse rows of mature teeth. Gut content contains detritus (50%), foraminifera (40%, about 100% calcareous shells) and sand (10%).
The studied specimen collected south of Tasmania, as well as individuals collected from Macquarie, differs from Norwegian individuals in the almost complete absence of radial grooves on the postmucronal area of the tail valve and the presence of granules on the top of the dorsal calcareous corpuscles (not metioned in the description by Kaas & Van Belle 1990).
Stenosemus exaratus and S. beui (O’Neill, 1987) have a very similar sculptured tegmentum but S. exaratus differs from S. beui by having slightly striated dorsal calcareous corpuscles (vs. coarse lattice-like sculptured, longitudinally ribbed corpuscles in S. beui), the head of major lateral teeth lacks a small appendix at its outer side (vs. head of major lateral teeth with small appendix at outer side in S. beui).
Notes
Files
Files
(4.0 kB)
| Name | Size | Download all |
|---|---|---|
|
md5:c0583f3eb20d05433e94bae2ecbaac79
|
4.0 kB | Download |
System files
(41.0 kB)
| Name | Size | Download all |
|---|---|---|
|
md5:ba453fd5726a8197d89caf35d98d00c7
|
41.0 kB | Download |
Linked records
Additional details
Identifiers
Biodiversity
- Collection code
- BL , CSIRO , NHMO
- Event date
- 1976-01-25 , 1999-01-22 , 1999-01-26 , 2007-03-31
- Family
- Ischnochitonidae
- Genus
- Stenosemus
- Kingdom
- Animalia
- Material sample ID
- D33573 , E 45526 , E 45535 , E 45537
- Order
- Chitonida
- Phylum
- Mollusca
- Scientific name authorship
- G. O. Sars
- Species
- exaratus
- Taxon rank
- species
- Type status
- syntype
- Verbatim event date
- 1976-01-25 , 1999-01-22 , 1999-01-26 , 2007-03-31
- Taxonomic concept label
- Stenosemus exaratus (Sars, 1878) sec. Sirenko, 2023
References
- Sars, G. O. (1878) Mollusca regionis Arcticae Norvegiae, Christiania, i-xiii, 466 pp.
- Haddon, A. C. (1886) Report on the Polyplacophora collected by H. M. S. " Challenger " during the years 1873 - 76. Challenger Reports, 15, 1 - 50, pls. 1 - 3.
- Thiele, J. (1906) Uber die Chitonen der deutschen Tiefsee-Expedition. Wissenschaftliche Ergebnisse der Deutschen Tiefsee-Expedition, 9 (2), 327 - 334, pl. 29.
- Dall, W. H. (1919) Descriptions of new species of chitons from the Pacific coast of America. Proceedings of the United States National Museum, 55, 499 - 516. https: // doi. org / 10.5479 / si. 00963801.55 - 2283.499
- Cotton, B. C. (1937) Loricata. Reports of the British Australian and New Zealand Antarctic Research Expedition, Series B, 4 (1), 9 - 19, figs. 1 - 29, pl. 1. [1929 - 1931]
- Leloup, E. (1956) Polyplacophora. Reports of the Lund University Chile expedition 1948 - 1949. Acta Universitatis Lundensis, New Series, 52, 1 - 94, figs. 1 - 53.
- Kaas, P. (1972) Polyplacophora of the Caribbean region. Studies on the fauna of Curacao and other Caribbean islands, 41 (137), 1 - 162, figs. 1 - 247, pls. 1 - 9. https: // doi. org / 10.5962 / p. 283216
- Dell, R. K. (1964) Antarctic and subantarctic Mollusca: Amphineura, Scaphopoda, and Bivalvia. Discovery Reports, 33, 93 - 250, figs. 1 - 4, pls 2 - 7.
- Kaas, P. (1979) On a collection of Polyplacophora (Mollusca, Amphineura) from the Bay of Biscay. Bulletin du Museum National d'Histoire Naturelle. Paris, 4 (A), A (1), 13 - 31, pls. 1 - 5.
- Ferreira, A. J. (1980) A new species of Lepidopleurus Risso, 1826 (Mollusca: Polyplacophora) in the deep waters of the Eastern Pacific. The Veliger, 23 (1), 55 - 61, figs. 1 - 6.
- Kaas, P. & Van Belle, R. A. (1990) Monograph of living chitons (Mollusca: Polyplacophora). Vol. 4 Suborder Ischnochitonina: Ischnochitonidae: Ischnochitoninae (continued). Additions to Vols. 1 - 3. E. J. Brill, Leiden, 298 pp. https: // doi. org / 10.1163 / 9789004431706
- Ferreira, A. J. (1981) A new species of Stenosemus Middendorff, 1847 (Mollusca: Polyplacophora) in the abyssal Northeastern Pacific. The Veliger, 23 (4), 325 - 328, figs. 1 - 9.
- Schwabe, E. & Sellanes, J. (2010) Revision of Chilean bathyal chitons (Mollusca: Polyplacophora) associated with cold-seeps, including description of a new species of Leptochiton (Leptochitonidae). Organisms Diversity & Evolution, 10 (1), 31 - 55. https: // doi. org / 10.1007 / s 13127 - 009 - 0002 - 6
- O'Neill, M. H. B. (1987) Lepidozona beui n. sp. (Mollusca: Polyplacophora) from New Zealand. New Zealand Journal of Zoology, 14, 131 - 134, figs. 1 - 3. https: // doi. org / 10.1080 / 03014223.1987.10422690