Austrothelphusa wasselli ( Bishop, 1963 )

Naser, Murtada D., Davie, Peter J. F. & Waltham, Nathan J., 2018, Redescription of Austrothelphusa wasselli (Bishop, 1963) (Crustacea: Brachyura: Gecarcinucidae), and designation of a new species from the Gilbert River, north Queensland, Australia, Zootaxa 4369 (1), pp. 109-127 : 114-119

Austrothelphusa wasselli ( Bishop, 1963)

( Figs 3 , 4 , 5 , 6A–C , 7A, C, E, F )

Parathelphusa wasselli Bishop, 1963: 229 –230, figs 1A, 2D, 4, pl. 1, fig. 1.

Material examined. Holotype (AM-P.14524), male (11.2 × 9.2 mm), Port Stewart District , Cape York, May-June 1954, J. L. Wassell. QM-W20049, 2 males (25.8 × 20.5 mm, 16.5 × 13.1 mm, Stewart River, Queensland, coll. B. Herbert, J. Peeters ( QDPI, CYPLUS), 21.04.1993 . QM-W29187, male (18.8 × 14.9 mm), Oscar Creek , 2.1 km SSE of Coen, Archer Catchment, Queensland, coll. K. McDonald, 8.05.2013.

Description. Small species (maximum CW of present material 25.8 mm). Carapace broadly oval ( Figs. 3A , 4A ); 1.26 times broader than long (n=3; CW> 16.6 mm); small specimens with less swollen branchial regions so typically narrower (holotype 1.21 times broader than long; CW 11.2 mm). Front projecting beyond level of exorbital angles, broadly bilobed, medial concavity shallow; inner part of supraorbital margin moderately welldefined, merging quite steeply with lateral slope of frontal lobe ( Fig. 7A ). Frontal and orbital margins with raised rim. Postfrontal (epigastric) lobes rounded, not well developed, lacking striated crests; separated by deep narrow groove. Postorbital region moderately depressed, short slightly convex crest laterally adjacent to, but not quite reaching, epibranchial tooth. Anterolateral margins smoothly cristate, evenly convex, with one distinct but small epibranchial tooth. Branchial regions not swollen, bearing punctations; anteriorly lacking striations but with striated ridges posterolaterally. Cervical groove shallow, relatively poorly defined; gastro-cardiac (H-shaped) grooves not strongly marked. Posterolateral borders straight, convergent posteriorly.

Male pleon ( Figs. 4B , 6C ) broadly triangular; telson tapering, apex rounded, length subequal to breadth at base. Somite 6 slightly tapering (proximal width 1.3 times distal width), c. 1.64 times wider at base than long.

Somite 5 more strongly tapering (proximal width 1.6 times distal width), c. 2.97 times wider at base than long. Somite 4 also strongly tapering (proximal width 1.52 times distal width), c. 4.4 times wider at base than long. Somites 2 and 3 broad, with lateral margins evenly rounded, narrow longitudinally. [The figure given of the pleon of A. wasselli by Bishop (1963: fig. 2D) appears to be in error by showing somite 5 to be longer than somite 6. This is not found in any other species of Austrothelphusa and does not represent the holotype ( Fig. 3C ) or other topotypic males in the present study.]

Walking legs moderately long, total length of P5 (basis to tip of dactyl) c. 1.1 times maximum carapace width. P5 ( Fig. 7C ): merus with anterior and posterior borders subparallel, slightly convex, 2.77 times longer than wide; propodus short, anterior border moderately convex, 1.94 longer than wide; dactylus short, similar in length to propodus (1.04 times).

G1 ( Fig. 7E, F ) short, broad basally but tapering and slender over distal half, moderately curved inward apically. Outer lateral margin (in sternal view) relatively straight (slightly concave) over basal two-thirds, before curving inwards towards apex. Terminal opening very small, V-shaped, apical flanges smoothly tapering. Some sparse long simple setae along inner margin towards tip.

Colour. Preserved material retains a smattering of tiny red dots on the anterolateral regions of the carapace. Live colours not recorded.

Distribution and ecology. Here recorded from the Stewart and adjacent Archer River Catchments, Cape York, Queensland ( Fig. 1 ). Holotype was collected from under leaves on the hard bottom of a temporary freshwater lagoon.

Remarks. Bishop (1963) described A. wasselli based on small specimens collected from the Port Stewart District, Cape York, with carapace widths ranging from 8 to 19 mm. Thus the biggest male we examined here (25.8 mm CW) is considerably larger than the types, but nevertheless it and our other samples agree in all morphological respects with the holotype ( Fig. 3 ). Although not designated as part of the type series, Bishop also identified samples from the Coen River, at Coen as being conspecific. While these two localities represent two separate catchments, the easterly flowing Stewart Catchment, and the westerly flowing Archer Catchment ( Fig. 1 ), we have not found any morphological differences, and the genetic divergence is low (1.8%), as is discussed more fully later. We therefore agree that A. wasselli does also occur in the Archer Catchment. This seems understandable because the two catchments are separated by only a low and narrow section of the McIlwraith Range to the east of Coen, with the creeks at the headwaters of each catchment being geographically very close.

Riek (1951: 354) reported Paratelphusa ( Liotelphusa ) planifrons ( Bürger, 1894) from the Mitchell Catchment (Walsh River and Mutchilba), but Bishop (1963: 229, 230) considered these samples to be a misidentification, and instead re-identified Riek’s samples as his own new species, A. wasselli ( Bishop, 1963) . However Bishop (as with the Coen River samples), specifically did not include them as part of his type series of A. wasselli . As part of a larger study of A. wasselli sensu lato, the present authors suspect that the crabs from the Mitchell River Catchment may belong to a discrete species for which the name Austrothelphusa plana (McCulloch, 1917) is likely to be available ( Geothelphusa leichardti var. plana McCulloch, 1917 , was described from Eureka Creek, Walsh River, within the Mitchell Catchment), and we have thus not included Riek’s identification as part of the synonymy for A. wasselli .

The type locality of “Cape York” for Telphusa planifrons Bürger, 1894, is now considered to have been erroneous, and it seems clear that T. planifrons is generically unrelated to Austrothelphusa (see Bott 1970: 50–51). Bishop (1963) identified six female crabs collected from the Upper Naru River, New Guinea as appearing to agree with Bürger’s (1894) description, thus inferring that Telphusa planifrons was most likely a New Guinean species. However, Bott (1970) pointed out that Bürger compared his T. planifrons with specimens he had identified as T.

transversa from Calcutta, but that species is otherwise indigenous to Australia. Thus the most parsimonious explanation is that the labels became mismatched, with the “Indian” T. tranversa coming from Australia, and the “Australian” T. planifrons from Calcutta, India. Bott (1970) somewhat inexplicably placed T. planifrons as a subspecies of Liothelphusa laevis , while otherwise stating in his remarks that its closest relative was L. bakeri (Alcock, 1909) [now in Globithelphusa, see Ng et al. 2008]. The holotype of Telphusa planifrons was originally deposited in the Göttingen Zoological Museum, but is now in the collections of the Senckenberg Museum, Frankfurt (SMF-ZMG699). It will need to be carefully re-examined, but from the description and figures of Bürger (1894) and of Bott (1970, pl. 7, figs 79–81) we agree with Bott (1970) that it cannot belong to Austrothelphusa and it looks most like a Globithelphusa species as indicated by Ng et al. (2008). In particular, “ Telphusa” planifrons has a strongly vaulted carapace, with the body much deeper than in Austrothelphusa species; and the front is longer significantly more deflexed, and the lateral margins subparallel, unlike anything seen in Austrothelphusa .

Figures

FIGURE 1. Map of Cape York, Queensland showing catchments and localities that were sampled for the present study. In the GilbertCatchment,black pentagon = Venture Creek, dark green hexagon = small branchof GilbertRiver,and purple diamond= Pleasant Creek; in the Normanby Catchment, light green spot= Healy Creek; in the Jeannie catchment, blue oval = Howick River; in the Stewart Catchment, red rectangle = Stewart River; and in the Archer Catchment, yellow triangle = Oscar Creek (see Table 1 for precise localities). The crab shown is the holotype male of Austrothelphusa gilbertensis sp. nov. (refer to Fig. 8).

FIGURE 3. Austrothelphusa wasselli, holotype male (11.2 × 9.2 mm), Port Stewart District, Cape York (AM-P.14524). A, dorsal view; B, frontal view; C, ventral view.

FIGURE 4. Austrothelphusa wasselli, male (25.8 × 20.5 mm) Stewart River, Queensland QM-W20049. A, dorsal view; B, ventral view of sternum and pleon.

FIGURE 6. A–C, Austrothelphusa wasselli, male (18.8 × 14.9 mm), Oscar Creek, 2.1 km SSE of Coen, Archer Catchment, Queensland (QM-W29187). D–F, A. gilbertensis sp.nov., holotype male (11.2 × 9.2 mm), Port Stewart District, Cape York (AM-P.14524).A, D, ventrofrontal view of cephalothorax (orbit, frontal triangle, epistome and pterygostome); B, E, left major chela; C, F, pleon. Scale line 5 mm.

FIGURE 7. A, C, E, F, Austrothelphusa wasselli, male (25.8 × 20.5 mm), from Stewart River, Queensland (QM-W20049). B, D, G, H, A. gilbertensis sp. nov., holotype male (22.3 × 17.6 mm), Venture Creek, E of Croydon, Gilbert Catchment, Queensland (QM-W28040). A, B, outline of frontal margin and orbits; C, D, fifth pereiopod; E–H, left first gonopod (sternal view) with magnification of apical part.

FIGURE5. Austrothelphusa wasselli, male (25.8 × 20.5 mm) Stewart River, Queensland QM-W20049.A, ventrofrontal view; B,outer view of major chela; C, ventrofrontal view showing chelae and third maxillipeds.