Conicostomatinae, Lowry & Stoddart, 2012

Lowry, J. K. & Stoddart, H. E., 2012, Australian and South African conicostomatine amphipods (Amphipoda: Lysianassoidea: Lysianassidae: Conicostomatinae subfam. nov.), Zootaxa 3248 (1), pp. 43-65 : 45

Conicostomatinae subfam. nov.

Diagnosis. Head partially covered by coxa 1 or completely covered by pereonite 1 and coxa 1. Epistome and upper lip fused. Maxilla 2 inner plate subequal in length to outer plate. Maxilliped coxa and basis enlarged; palp article 4 reduced or absent. Mouthpart bundle subconical. Gnathopod 1 simple; propodus small; dactylus slightly curved. Urosome compressed.

Included genera. Acontiostoma Stebbing, 1888 ; Amphorites gen. nov.; Conicostoma Lowry & Stoddart, 1983 ; Ocosingo J.L. Barnard, 1964 ; Scolopostoma Lowry & Stoddart, 1983 and Stomacontion Stebbing, 1899 .

Remarks. Lowry & Stoddart (1983) also included in their ‘conicostomatid’ group the genera Acidostoma Lilljeborg, 1865 , Phoxostoma K.H. Barnard, 1925 , Shackletonia K.H. Barnard, 1931 and Socarnoides Stebbing, 1888 (type species only). Further study has shown that these genera, although they do have conical or subconical mouthpart bundles, do not belong in the conicostomatine group; Acidostoma and Shackletonia have recently been assigned to a new lysianassoid family, Acidostomatidae by Lowry & Stoddart (in press); Phoxostoma and Socarnoides remain for now in the subfamily Lysianassinae . Phoxostoma differs from conicostomatines in having the outer plate of maxilla 2 offset from the inner plate and in not having a compressed urosome. Socarnoides has a left lacinia mobilis, the epistome and upper lip separate and does not have a compressed urosome – all characters that exclude it from the conicostomatines.

The genus Stomacontion is problematic ( Lowry & Stoddart 1983; Rauschert 1997). It has in the past contained too much generic level variability. One set of species formerly considered in the genus contain a synapomorphy in the form of a vase-shaped palp on maxilla 1. In this paper we remove these taxa to the new genus Amphorites and this appears to stabilise the Stomacontion concept. The very poorly known taxon, Stomacontion capense K.H. Barnard, 1916 , cannot be placed in a genus and is considered as incertae sedis. It is possible that S. insigne and S. bulbus are synonyms.