Ferreiraella plana ( Nierstrasz, 1905 )

Sigwart, Julia D. & Sirenko, Boris I., 2012, Deep-sea chitons from sunken wood in the West Pacific (Mollusca: Polyplacophora: Lepidopleurida): taxonomy, distribution, and seven new species, Zootaxa 3195, pp. 1-38 : 27

Ferreiraella plana ( Nierstrasz, 1905)

Lepidopleurus planus Nierstrasz 1905: 9 , figs 6, 56–59.

Leptochiton planus: Kaas & Van Belle 1985: 114 –116, fig. 50, map 22.

Ferreiraella plana: Sirenko 1988: 1782 ; 1997b: 81; 2001: 59–61, figs 147–161, figs 192–195; 2004: 1, table 1; Sigwart et al. 2007: appendix 1; Schwabe 2008: 212; Sigwart, 2009b: 457; Sigwart et al. 2011: table 3, fig. 1E, 2; Yearsley & Sigwart 2011: table 1.

Material examined. Holotype (ITZ). 20 specimens in 7 lots from Vanuatu, 6 specimens in 1 lot from the Solomon Islands.

Distribution. Prior to Sirenko’s (2001) report, F. plana was known only from the holotype collected in Indonesia (3.45°N 125.31°E: Nierstrasz 1905). Sirenko’s (2001) study extended the known range of this species south to New Caledonia. Found living and feeding on sunken terrestrial plant remains, from 560–799 m with deeper records at 1040 m in Vanuatu (Boa 1 sta. CP2434) and 2053 m in Indonesia (holotype: Nierstrasz 1905).

Remarks. The material reported here is distributed in the intermediate part of the range of F. plana . However, no specimens were recovered in the material examined from the Philippines [Panglao 2005]; the northernmost record of this species in the present material is 7.65°S, 157.72°E.

The holotype of L. planus is preserved as a dried specimen and is in poor condition, and the radula has been lost. Nierstrasz (1905) reported the ventral side of the girdle to be naked; Kaas & Van Belle (1985) reported the morphology of the ‘ventral’ spicules. Sirenko (2001) speculated that the poor preservation of the specimen may have led to some confusion over the existence of ventral girdle armature. However, a slide preparation of the girdle of the holotype of L. planus does clearly show five rows of differentiated median or ventral spicules that are distinct from the dorsal armature. The statement that ferreiraellids are ventrally ‘naked’ is a slight over-generalisation; these species do have differentiated non-dorsal girdle armature in that they have a distinct marginal fringe.