Acanthochitona

Acanthochitona crinita, copyright Serge Gofas.

Belongs within: Ischnochitonina.

Acanthochitona is a cosmopolitan genus of chitons in which the dorsum of valves is ornamented with a sculpture of rounded nodules (Smith 1960).

Characters (from Smith 1960): Small to medium-sized chitons, rather narrow and elongated, tegmentum sculpture consisting of separated nodules or pustules of round to tear-drop shape, generally arranged in radial lines or rows. Valve coverage complete. Tail valves with submedian mucro and no dorsal ribs. Insertion plates generally with five slits in head valve, one on each side of intermediate valves, and in tail valve one on each side with a wide shallow sinus between; all teeth sharp and nearly smooth; sutural laminae large. Girdle varying from nude to densely hairy, but invariably with series of bristle-bearing pores (normally 18), situated around head valve with single row on each side at valve sutures.

<==Acanthochitona Gray 1821 SF77 (see below for synonymy)
    |--*A. fascicularis (Linné 1766) S60 [=Chiton fascicularis S60, *Acanthochiton fascicularis P61]
    |--A. achates [=Chiton (Acanthochaetes) achates] C64
    |--A. adelaidae S60
    |--A. arragonites (Carpenter 1857) SF77
    |--‘Acanthochites’ asbestoides (Smith 1884) [=Chiton asbestoides] H09
    |--A. avicula (Carpenter 1866) [=Acanthochites avicula] SF77
    |--‘Acanthochiton’ brookesi Ashby 1926 P61
    |--‘Acanthochiton’ costatus A23
    |--A. crinita GO06
    |--A. crocodilus S60
    |    |--A. c. crocodilus S60
    |    `--A. c. debilior S60
    |--A. diegoensis Pilsbry 1893 [=A. arragonites var. diegoensis] O27
    |--A. hirudiniformis (Sowerby 1832) (see below for synonymy) SF77
    |--A. jacquelinae Smith & Ferreira 1977 SF77
    |--A. mariae HS01
    |--A. pilsbryoides S60
    |--A. retrojecta H15
    |--‘Acanthochiton’ speciosus A23
    |--A. spiculosa S60
    |--A. stygma (Rochebrune 1889) SF77
    |--‘Acanthochiton’ subviridis A23
    |--‘Acanthochiton’ thileniusi Thiele 1909 P61
    |--A. trianguloides S60
    |--A. violacea HS01
    `--A. zelandica (Quoy & Gaimard 1835) HS01, P61 [=Acanthochiton zelandicus P61]
         |--A. z. zelandica P61
         |--‘Acanthochiton zelandicus’ amplificatus Iredale & Hull 1930 P61
         `--‘Acanthochiton zelandicus’ hookeri Gray 1843 P61

Acanthochitona Gray 1821 SF77 [=Acanthochaetes (l. c.) S60, Acanthochetes (l. c.) S60, Acanthochistes (l. c.) S60, Acanthochites Leach in Risso 1826 S60, Acanthochiton Iredale 1915 S60, Acanthochitus (l. c.) S60, Acanthochoetes (l. c.) S60, Acanthocites (l. c.) S60, Acantochiton (l. c.) S60, Acantoctites (l. c.) S60; incl. Amycula Adams in Tapparone-Canefri 1874 S60, Chitonellus deBlainville 1825 non Lamarck 1819 S60, Crocochiton Cotton & Weeding 1939 S60, Eoplax Ashby & Cotton 1936 S60, Hamachiton Middendorff 1848 S60, Meturoplax Pilsbry 1894 S60, Phacellopleura Agassiz 1846 S60, Phacelopleura (l. c.) S60, Phakellopleura Guilding 1830 S60, Pseudoacanthochiton Šulc 1934 S60, Stectoplax Carpenter in Dall 1882 S60, Strecochiton Adams in Tapparone-Canefri 1874 S60, Stretochiton (l. c.) S60]

Acanthochitona hirudiniformis (Sowerby 1832) [=Chiton hirudiniformis, Acanthochites hirudiniformis, Tonicia hirudiniformis; incl. Acanthochitona coquimbensis Leloup 1941, Acanthochitona peruvianus Leloup 1941, Acanthochitona tabogensis Smith 1961] SF77

*Type species of generic name indicated

REFERENCES

[A23] Ashby, E. 1923. A new species and sub-species of Acanthochiton. Journal of the Royal Society of Western Australia 10 (4): 13–16.

[C64] Carpenter, P. P. 1864. Supplementary report on the present state of our knowledge with regard to the Mollusca of the west coast of North America. Report of the British Association for the Advancement of Science 33: 517–686.

[GO06] Giribet, G., A. Okusu, A. R. Lindgren, S. W. Huff, M. Schrödl & M. K. Nishiguchi. 2006. Evidence for a clade composed of molluscs with serially repeated structures: monoplacophorans are related to chitons. Proceedings of the National Academy of Sciences of the USA 103 (20): 7723–7728.

[HS01] Hayward, B. W., A. B. Stephenson, M. S. Morley, W. M. Blom, H. R. Grenfell, F. J. Brook, J. L. Riley, F. Thompson & J. J. Hayward. 2001. Marine biota of Parengarenga Harbour, Northland, New Zealand. Records of the Auckland Museum 37: 45–80.

[H09] Hedley, C. 1909. The Marine Fauna of Queensland: Address by the President of Section D. Australasian Association for the Advancement of Science: Brisbane.

[H15] Hedley, C. 1915. Presidential address. Journal and Proceedings of the Royal Society of New South Wales 49 (1): 1–77, pls 1–7.

[O27] Oldroyd, I. S. 1927. The Marine Shells of the West Coast of North America vol. 2 pt 3. Stanford University Press: Stanford University (California).

[P61] Powell, A. W. B. 1961. Shells of New Zealand: An illustrated handbook 4^th ed. Whitcombe and Tombs Limited: Christchurch.

[S60] Smith, A. G. 1960. Amphineura. In: Moore, R. C. (ed.) Treatise on Invertebrate Paleontology pt I. Mollusca 1: Mollusca—General Features, Scaphopoda, Amphineura, Monoplacophora, Gastropoda—General Features, Archaeogastropoda and some (mainly Paleozoic) Caenogastropoda and Opisthobranchia pp. I41–I76. Geological Society of America, and University of Kansas Press.

[SF77] Smith, A. G., & A. J. Ferreira. 1977. Chiton fauna of the Galápagos Islands. Veliger 20 (2): 82–97.