Ausatelson ule J. L. Barnard 1972

Ausatelson ule

DESCRIPTION.—Pereonite 4 greatly elongate and bulging dorsally; pereonite 5 with lateral ridge locking posterodorsal margin of coxa 4; rostrum of medium size; eyes red in formaldehyde, colorless in alcohol; anterolateral corner of head quadrate; article 1 of antenna 1 with large anterodistal process, articles 2–3 subequal to each other in length, accessory flagellum absent; antenna 2 with article 3 curving medially around front of head, article 5 longer than 4; epistome unproduced, upper lip bilobate slightly asymmetrically; mandible bearing 1-articulate palp (both sides) with 2 apical setae, left lacinia mobilis deeply serrate, right smooth and minutely tuberculate; lower lip with 1 cone on each main lobe, mandibular process obsolescent; palp of maxilla 1 biarticulate, outer plate with 6 spines, inner with 1 long seta; maxilla 2 very small, inner lobe very short (Figure 190X2); inner plates of maxilliped with 2 spines and with or without 1 long seta, palp article 4 without distinct distal nail but apex extremely sharp; coxa 4 with deep lateral pit, invagination pushing inward toward dorsal margin; pereopod 2 much smaller than pereopod 1; gnathopod 1 with palm very oblique, defined by 2–3 stout spines in tandem, dactyl smooth; palm of gnathopod 2 weakly oblique but well defined by slight hump and 2 spines, palm minutely denticulate, dactyl smooth; article 2 of pereopods 3–5 rectolinear, dactyls of all pereopods with apical hook and comb row of pectinations; pleonal epimera 1–2 with softly quadrate posteroventral corners; pleonite 3 weakly inflated dorsally, pleonite 4 with 1 lateral ridge on each side and slight dorsal depression between ridges, pleonites 5 and 6 small and not distinctly separate from each other except distally; telson huge, vertically compressed, lateral surface area subequal to lateral surface area of pleonite 4; uropods 1–3 very slender and elongate, uropod 3 uniramous, ramus biarticulate, article 2 slightly shorter than article 1; body and major coxae covered with small craters and occasional setule, pits and rugosities especially gross on dorsal margins of pleonite 4 and telson.

HOLOTYPE.—WAM, female, 2.2 mm.

TYPE-LOCALITY.—JLB Australia 5, west of Bunker Bay, Cape Naturaliste, Western Australia, intertidal, wash of algae and rocks, 2 September 1968.

RELATIONSHIP.—This species differs from Pseudothaumatelson cyproides Nicholls (1938) in the absence of a dorsal process on pleonite 4, the enlarged hand of gnathopod 2, and the larger telson.

MATERIAL.—The holotype; Shepherd 52 (1).

DISTRIBUTION.—Southwestern and South Australia, intertidal.

Goratelson, new genus

DIAGNOSIS.—Gnathopods 1–2 subchelate, with fully oblique palms, gnathopod 2 much larger than 1; mandible lacking palp; palp of maxilla 1 biarticulate; antenna 1 lacking nasiform processes; article 2 of pereopods 3–5 rectangular but not linear, pereopods 4–5 with distinct posteroventral lobe on article 2; pereonite 4 not elongate; pleonites 4–6 coalesced, telson huge, very broad and low but with slight increase in elevation, fully covering urosome, but lateral surface aspect with area equivalent to lateral area of urosome; pleonite 3 dorsally tumid but lacking process; inner plate of maxilla 2 unproduced.

TYPE-SPECIES.—Goratelson warroo, new species.

RELATIONSHIP.—This thaumatelsonin has little relationship to other thaumatelsonins in the absence of elongation on pereonite 4, the nonlobular inner plate of maxilla 2, and the stout article 2 of pereopods 3–5. The gross telson represents a stage intermediate between that of normal stenothoids and the fully erect telson of the ultimate thaumatelsonin. Goratelson demonstrates the lack of phyletic integrity in the thaumatelsonin concept, as, having an extremely thin article 2 on pereopods 3–5, a well-developed inner plate of maxilla 2, and an elongate pereonite 4, it apparently has been derived from an immediate stenothoid ancestor entirely different from that of other thaumatelsonins.