Acidostoma australis, Stoddart & Lowry, 2012

Stoddart, H. E. & Lowry, J. K., 2012, Revision of the lysianassoid genera Acidostoma and Shackletonia (Crustacea: Amphipoda: Acidostomatidae fam. nov.), Zootaxa 3307 (1), pp. 1-34 : 5-8

Acidostoma australis sp. nov.

( Figs 1–4 )

Type material. HOLOTYPE, sex not known, probably female, 5 mm, AM P.25478, east of Port Kembla, New South Wales, Australia, 34°26–27'S 151°27'E, 1200 m, Globigerina ooze, dredged, 13 December 1976, J.K. Lowry, FRV Kapala stn K76-23-02.

1. Dahl wrote that “to study the structure and contents of the alimentary canal one specimen of A. laticorne was sectioned serially” and “the proctodaeum was filled with a tangle of tubular objects, many of which contained a spiral thread-like structure. Obviously these objects are nematocysts, most probably of Anthozoan origin.” Ansell (1969) and Vader (1967; 1984) have cited these statements as evidence for the association of A. laticorne with sea anemones. However, Dahl’s next sentence stated that “In conjunction with the observations published by Della Valle this seems to indicate that A. neglectum is an ectoparasite of Anthozoans.” It seems that his earlier use of the name A. laticorne was a mistake, the intended species being A. neglectum . This is supported by Dahl’s next two sentences, where he says that the mouthparts of A. obesum and A. nodiferum are similar, but those of A. laticorne are less specialized; and that “no new data are available concerning the food of any one of the three species”- presumably the three species just mentioned, A. obesum , A. nodiferum and A. laticorne . It is also unlikely that, given there is so little material of A. laticorne available, any specimen would be sacrificed for serial sectioning.

Diagnostic description. Mandible molar a small, weakly setose triangular flap. Maxilla 1 palp small, 1- articulate, with apical robust setae. Maxilliped inner plate well developed; outer plate with subapical notch. Gnathopod 2 dactylus reaching corner of palm. Pereopods 5 and 6 merus broader than long. Epimeron 3 posteroventral corner produced, subacute. Uropod 1 peduncle dorsolateral margin with less than 10 robust setae. Uropod 2 peduncle dorsolateral margin not castellate, with very short setae. Uropod 3 reaching to about the end of uropod 2; rami longer than peduncle, without plumose setae; outer ramus article 2 well developed. Telson about as long as broad, deeply cleft (about 80%).

Etymology. Named for Australia, the geographic area of the type locality.

Distribution. South-eastern Australia, Tasman Sea; 1200 m depth.

Figures

FIGURE 1. Acidostoma australis sp. nov., holotype, 5 mm, AM P.25478, east of Port Kembla, New South Wales, Australia.

FIGURE 2. Acidostoma australis sp. nov., holotype, 5 mm, AM P.25478, east of Port Kembla, New South Wales, Australia. Scales represent 0.1 mm.

FIGURE 3. Acidostoma australis sp. nov., holotype, 5 mm, AM P.25478, east of Port Kembla, New South Wales, Australia. Scale represents 0.1 mm.

FIGURE 4. Acidostoma australis sp. nov., holotype, 5 mm, AM P.25478, east of Port Kembla, New South Wales, Australia. Scale represents 0.1 mm.