Acanthaxius garawa, Poore & Collins, 2009

Poore, Gary C. B. & Collins, David J., 2009, Australian Axiidae (Crustacea: Decapoda: Axiidea), Memoirs of Museum Victoria 66 (2), pp. 221-287 : 227-230

Acanthaxius garawa sp. nov.

Figures 4 , 5

Material examined. Holotype. Qld, Gulf of Carpentaria , 12°10.5'S, 139°56.7'E (stn SS05-1991 040, A.J. Bruce), 59 m, 25 Nov 1991, NTM Cr008808 (male, cl. 9.9 mm, tl. 28 mm).

Paratype. Qld, Gulf of Carpentaria , 11°25.2'S, 139°25.2'E (stn SS05-1991 054, A.J. Bruce), 49 m, 28 Nov 1991, NTM Cr009067 (male, cl. 10.0 mm, tl. 28 mm) .

Description of male holotype. Carapace heavily spinulose. Rostrum 0.2 times length of front-to-cervical, acute, with 4 lateral spines anterior to supraocular spine, weakly continuous with lateral gastric carinae. Supraocular spines moderately prominent. Lateral gastric carina with 10 spines. Submedian gastric carina duplicated, external row with 10–12 spines, internal with 10–12 spines. Median gastric carina with about 20 spines. Sternite 7 (pereopod 4) deeply divided in midline over posterior two-thirds and with sharp oblique lateral ridge. Sternite 8 (pereopod 5) with setose semicircular flap on anterior face at base of leg. Abdominal pleuron 1, 1.4 times as deep as middorsal length, ventrally obtuse; pleuron 2 broad, lateral length as long as dorsal length, anteroventrally rounded; pleura 3–5 becoming more ventrally quadrate, each with small anteroventral tooth; pleuron 6 rounded, with small anteroventral tooth; pleura 1–5 without lateral crease, slightly flared laterally.

Eyestalk, 1.6 length of rostrum; cornea weakly pigmented. Antennular peduncle reaching to middle of antennal article 5. Antennal article 1 with 1 spine and 3 spinules on distoventral margin; article 2 distal spine slender, directed slightly inwards, reaching distally to middle of antennal article 4; scaphocerite slightly curved, reaching distally to just beyond midpoint of article 4; article 3 with with 4 spines on mesial lower margin; article 4 about two-thirds length of article 2 (excluding distal spine), with distoventral spine; article 5 about half length of article 4. Maxilliped 3 basis with 1 spine; ischium with 2 spines on lower margin; crista dentata with ~24 teeth; merus with 3 spines; carpus with 1 spine.

Pereopods 1 asymmetrical, propodus of major more swollen, 1.15 times as long as minor. Major pereopod 1 (left) coxa lower margin with 2 spines; basis lower margin without spine; ischium lower margin with 3 spines; merus upper margin convex, with 4 spines, lower margin with 10 spines, lateral face spinose distally near upper margin, mesial face rugose distally; carpus upper margin with 6 spines, lower margin with 3 spines laterally, 1 spine mesially, lateral face tubercular, mesial face with 3 spines plus others smaller; propodus upper margin with row of 7 spines, lower margin with 12 spines in lateral row and obsolete mesial row, lateral face covered with dome-like tubercles, mesial face covered with larger distinct tubercles, with 1 spine near gape; fixed finger 1.2 times length of upper palm, cutting edge straight, with c. 20 irregular rounded teeth; dactylus upper margin with 8 spines, lateral face with row of blunt spines, mesial face with row of 6 spines and denticles, cutting edge as in fixed finger; both fingers bearing setae.

Minor pereopod 1 coxa, ischium as in larger cheliped; merus upper margin with 5 spines, lower margin with 7 spines; carpus upper margin with 6 spines, lower margin with 4 spines laterally, 1 spine mesially, lateral face weakly spinose, mesial face with 3 spines; propodus upper margin with 5 spines, lower margin with 7 spines in lateral row and 7 spines in mesial row, lateralfaceweaklytuberculate,mesialfacegrosslytuberculate, with 2 spines near gape; fixed finger 2.5 times length of upper palm, cutting edge with c. 40 irregular teeth; dactylus upper margin with 6 spines, lateral face with proximal row of 5 spines, mesial face with row of 4 denticles, cutting edge as in fixed finger; both fingers setose as in major pereopod.

Pereopod 2 ischium lower margin with 1 distal spine; merus lower margin with 4 spines; carpus about as long as chela; propodus upper margin 0.8 length of dactylus. Pereopod 3 merus lower margin with 5 strong spines; carpus with 1 spine; propodus 1.9 times as long as dactylus, with 7 marginal robust setae (some duplicated). Pereopod 4 missing. Pereopod 5 propodus 2.5 times as long as dactylus, subchelate, with short fixed finger; dactylus with broad blade on cutting edge.

Pleopods 2–5 appendix interna one quarter length of endopod; appendix masculina just exceeding appendix interna.

Telson about as long as broad, lateral margin with proximal tooth, distal margin broadly convex, with posteromedian spine, posterolateral angle with 1 minute tooth and 2 robust setae; dorsal face with 2 spines in each oblique row. Uropodal endopod 2.0 times as long as wide, with 2 lateral and 1 distolateral spines, longitudinal ridge with 5 spines (including marginal). Uropodal exopod 1.8 times as long as wide, with 4 lateral spines, 2 longitudinal ribs (outer rib with 1 spine), posterolateral angle with 1 fixed spine and 1 robust seta; transverse suture with 6 spines.

Etymology Garawa is an Australian Aboriginal language which was spoken in the Gulf of Carpentaria region close to the Northern Territory-Queensland border.

Distribution. Qld, Gulf of Carpentaria, 12°S, 140°E, 49–59 m depth (known only from the type locality).

Remarks. With its spinose carapace, Acanthaxius garawa is closest to A. ningaloo sp. nov. described below. It differs in having tubercles rather than sharp spines on lateral and mesial faces of the chelipeds and the rostrum being shorter than the eyes. The tubercles on the mesial face of the major cheliped are strikingly prominent. See the Remarks following A. ningaloo for differences from other similar Indo-West Pacific species.

Figures

Figure 4. Acanthaxius garawa sp. nov. a, lateral view. b, dorsal view of carapace, peduncles of antennule and antenna. c, telson and left uropod. d, major pereopod 1 (left, lateral). e, same (propodus–dactylus, without setae, mesial). f, same (carpus–propodus, without setae, lower). g, minor pereopod 1 (right, lateral). h, same (propodus–dactylus, without setae, mesial). i, same (carpus–propodus, without setae, lower). All figures from holotype.

Figure 5. Acanthaxius garawa sp. nov. a, maxilliped 3 (without setae). b, male pleopod 2. c, pereopod 2 (right). d, pereopod 3 (right). e, pereopod 5 (right). All figures from holotype.