Akanthophoreus

Bird, Graham J, 2007, Family incertae cedis *, Zootaxa 1599, pp. 121-149 : 127-128

Akanthophoreus cf gracilis ( Krøyer, 1842)

(Restricted synonymy and bibliography)

Leptognathia gracilis ( Krøyer, 1842) : Kudinova-Pasternak, 1970: 354 –355, fig. 8 [an uncertain synonym]. Kudinova-Pasternak, 1976: 118 –119, [an uncertain synonym]. Kudinova-Pasternak, 1984: 829 [an uncertain synonym]. Lang, 1957: 13 –30, figs G–M, O–P.

Leptognathia longiremis ( Lilljeborg, 1864) : G.O. Sars, 1896: 27, plate XII (not longiremis sensu Lilljeborg, 1864 . Leptognathia Sarsii Hansen, 1901 : Hansen, 1909: 229 –231, plate V fig 3a–b.

Paraleptognathia gracilis ( Krøyer, 1842) : Guerrero-Kommritz, 2004: 25 –30, figs 9–10.

See Sieg (1983) for the very complex synonymy and bibliography up to date of publication.

Remarks. In the Japanese region, under the name Leptognathia gracilis , this species has been recorded from the Kurile-Kamchatka Trench at 4895–6710 metres ( Kudinova-Pasternak 1970), the Japan Trench, 7370 metres ( Kudinova-Pasternak 1976), and more widely from the shelf and bathyal of the Sea of Japan, 200– 1900 metres ( Kudinova-Pasternak 1984). It is very probable that species such as Akanthophoreus undulatus n.sp. and Akanthophoreus sp.KK#1 could have (understandably) accounted for the earlier abyssal and hadal records, which should now perhaps be regarded with scepticism. Because of the complexity of this taxon and related species, further study of the shallower Japanese tanaidacean fauna is also required to validate or disregard these records of A. gracilis .