Lepidepecreellidae, Stoddart & Lowry, 2010

Stoddart, H. E. & Lowry, J. K., 2010, Lepidepecreellidae fam. nov. (Crustacea: Amphipoda: Lysianassoidea) in Australian waters, Zootaxa 2634 (1), pp. 63-68 : 64

Lepidepecreellidae fam. nov.

Diagnostic description. Head exposed, much deeper than long, not extending much below insertion of antenna 2, without cheek notch. Antennae calceoli absent in male and female. Antenna 1 callynophore present in male and female. Antenna 2 peduncular article 3 without distal hook. Epistome and upper lip fused, with proximal portion produced into large triangular keel. Mouthpart bundle subquadrate or subconical. Mandible incisors well developed, symmetrical, left and right straight, smooth; right lacinia mobilis absent; accessory setal row with 5 or less robust setae, without distal setal tuft; molar vestigial or small, flap-like, weakly setose to asetose; palp present, inserted approximately midanteriorly. Maxilla 1 inner plate without apical pappose setae; outer plate with (10–11) setal-teeth in 7/4 arrangement, setal-teeth large, setal-tooth 6 slender, setal-tooth 7 slender, setal-tooth 7 contiguous with setal-tooth 6; palp large, 1- or 2-articulate, without apical robust setae. Maxilla 2 inner plate subequal to or slightly shorter than outer plate, without oblique row of facial setae. Maxilliped coxa and basis normal; outer plate present, medial setae vestigial or absent, without apical setae; palp 4-articulate, article 4 well developed.

Gnathopod 1 simple; coxa vestigial; ischium long (length 3–3.6 x breadth); merus and carpus not rotated; carpus elongate; propodus linear, elongate; dactylus filiform, rarely not so. Gnathopod 2 coxa vestigial; propodus with palmate setae; dactylus minute. Pereopods all simple; distal spurs absent. Pereopod 3 coxa large. Pereopod 4 coxa with well-developed posteroventral lobe. Pereopod 5 coxa posterior lobe much deeper than anterior lobe. Pereopod 6 coxa posterior lobe much deeper than anterior lobe.

Uropod 2 inner ramus without constriction. Uropod 3 uniramous. Telson entire.

Type genus. Lepidepecreella Schellenberg, 1926 .

Generic composition. Lepidepecreellidae includes one genus: Lepidepecreella Schellenberg, 1926 .

Remarks. Lepidepecreellids are difficult to categorise. Based on the 7/4 setal-tooth arrangement, the nontriturating, flap-like molar and the simple gnathopod 1 the group appear to be most similar to scopelocheirids, but gnathopod 1 in scopelocheirids is modified in a different way to that of lepidepecreellids and no scopelocheirids have an entire telson or vestigial first and second coxae.

Among the lysianassoids, aside from the lepidepecreellids, only cyphocarids, the cebocarid, cyclocarid and thoriellid groups and wandinids have vestigial first and second coxae. None of these groups have a nontriturating, flap-like molar, none have a well-developed posteroventral lobe on coxa 4, none have a uniramous third uropod and none have a 7/4 setal-tooth arrangement. Cyphocarids and wandinids have a 6/5 setal-tooth arrangement.

There is evidence to suggest that species of Lepidepecreella are highly derived epi-parasites on sea urchins with a world-wide distribution in the deep-sea. Their relationship to other lysianassoid family level groups is unresolved at this time.