Paraxiopsis pumilus ( Sakai, 1994 )

Poore, Gary C. B. & Collins, David J., 2009, Australian Axiidae (Crustacea: Decapoda: Axiidea), Memoirs of Museum Victoria 66 (2), pp. 221-287 : 266-267

Paraxiopsis pumilus ( Sakai, 1994)

Figures 30 , 31 , 44

Eutrichocheles pumilus Sakai, 1994: 188–192 , figs. 8, 9. Paraxiopsis pumilus .— Kensley, 2003: 373

Paraxiopsis dianae Poore, 2008: 165–168 : fig. 2. (syn. nov.)

Material examined. WA, off Barrow I., 20°59.05'S, 114°54.25'E – 20°59.40'S, 114°54.32'E (stn SS10-2005 170), 101– 100 m, 13 Dec 2005, NMV J53449 (male, cl. 8.3 mm, tl. 21.5 mm). WA, Bonaparte Archipelago, Port George IV (15°23.474'S, 124°37.793'E), 10–16 m, 8 Oct 2007, J. James (stn P23), NMV J59647 (4 juvenile females, cl. 4.8–6.0 mm; female, cl. 7.3 mm)

NT. W side of Barrow Bay , Port Essington (11°22.0'S, 132°12.0'E), low water, J. R. Hanley, 18 Sep 1985 (stn CPV8 ), NTM Cr 013204 (1 female) , NTM Cr 013205 (1 female) . Arafura Sea , 09°36.63'S, 134°10.95'E – 09°36.59'S, 134°10.87'E (stn SS05-2005 BS014 ) , 95 m, 25 May 2005, AM P74506 (1 juvenile) .

Distribution. NT, Cobourg Penisula, Arafura Sea; WA, Barrow Island—Dampier Archipelago, c. 9°– 21°S, 115°– 132°E, 6–100 m depth.

Remarks. The species is distinguished from other species of Paraxiopsis by the possession (in adults) of two pairs of spines at the base of the tapering rostrum and none on the submedian gastric carina ( Kensley, 2003). Poore (2008) compared his new species, Paraxiopsis dianae , with several descriptions of the similar species, P. brocki De Man, 1888 , and concluded that probably more than one species over a wide geographical range had been referred to the latter name. He did not compare it with P. pumilus ( Sakai, 1994) , described as a species of Eutrichocheles , from the Northern Territory and north-western WA. For this paper, topotypic material was compared with the WA material. Sakai figured the tail fan, gastric region and rostrum of two individuals of P. pumilus . The number of lateral spines on the rostrum differed between these two and between individuals in the new collections from WA and NT. On small individuals lateral spines are absent, in others there is one spine on one or both sides, in addition to the supraocular spine (fig. 31). The two individuals of P. dianae fall within this range of variability and the species must be synonymised with P. pumilus .

Most species of Paraxiopsis and Eutrichocheles possess a bifid scaphocerite and illustrations of type material of both Paraxiopsis pumilus and P. dianae show this. Some specimens possess a simple comma-shaped scaphocerite on both antennae, a difference we do not consider of specific importance (cf. figs. 30b, 31g, h). Paraxiopsis johnstoni Edmondson, 1925 from Hawaii was also illustrated with a simple scaphocerite but has a different carapace.

Type material of the two nominal Australian species was collected at 6–40 depth; the new specimen is from 100 m depth but at a similar latitude.

Figures

Figure 30. Paraxiopsis pumilus (Sakai, 1994). a, lateral view. b, dorsal view of carapace, peduncles of antennule and antenna. c, telson and right uropod. d, thoracic sternites 7 and 8, abdominal somite 1 with pleopods 1. e, left thoracic sternites 7 and 8, abdominal somite 1 with pleopod 1 (lateral). f, epistome, left antennule and antenna (ventral). g, maxilliped 3. h, major pereopod 1 (right, lateral). i, male pleopod 2. All figures from male, cl. 8.3 mm, NMV J53449.

Figure 31. Paraxiopsis pumilus (Sakai, 1994). a–c, pereopods 2–4. d–h, anterior carapace, peduncles of antennule and antenna and rostrum of five individuals, cl. 4.8, 4.8, 5.2, 6.0, 7.3 mm. Figs a–c from male, cl. 8.3 mm, NMV J53449; figs. d–e from male, 7.3 mm, NMV J59647.

Figure 44. Paraxiopsis pumilus (Sakai, 1994). Photomicrographs of (left to right) maxilla 1, maxilla 2 (posterior epipod seta truncated), maxilliped 1, maxilliped 2.