Austinograea chubacarc Guinot, 2025, n. sp.

Austinograea chubacarc n. sp. (Figs 3-7; 8A, B) urn:lsid:zoobank.org:act: 4946C58F-0337-4C49-8898-CF60271B3265 Austinograea sp. – Boulart et al. 2022: 7, 8,?fig. 5c, e. Crabs – Hourdez & Jollivet 2023: 74, tables 10, 11. TYPE LOCALITY. — Woodlark Basin, La Scala vent Field. TYPE MATERIAL. — Holotype. SW Pacific • ♂ 22.8 × 35.7 mm, right-handed; Woodlark, La Scala vent Field; PL738 - ASPI2; 9°47.943’S, 155°3.160’E; 3388 m; 27.V.2019; CHUBACARC 2019 cruise; Hourdez det. Austinograea; Chu-025 writen on carapace; MNHN-IU-2024-6548. Paratypes. SW Pacific • 1 ♂ 6. 3 × 8.1 mm, right-handed, 1 juvenile ♂ 9.8 × 14.6mm, 1 ♀ 8.5 × 12.4 mm; Woodlark, La Scala vent Field; PL738 - ASPI3; 9°47.943’S, 155°3.160’E; 3374 m; 27.V.2019; CHUBACARC 2019 cruise; Hourdez det. Austinograea hourdezi; MNHN-IU-2024-6549 • 1 ♀ 13.5 × 19, 3 mm; same data as for preceding; Chu-026 writen on carapace; MNHN-IU-2024-6550 • 1 ♀ 24.7 × 39.2 mm, with two chelae gaping; Woodlark, La Scala, PL738 - GBT10; 9°47.943’S, 155°3.164’E; 3388 m; 27.V.2019; CHUBACARC 2019 cruise CHU-027; MNHN-IU-2024-6092 • 1 ♀ 28.6 × 45.7 mm, right-handed, but cutter bigger than crusher; same data as for preceding; CHU-028; MNHN-IU-2018-5228 • 1 ♀ 18.2 × 28.3 mm, slightly right-handed; same data as for preceding; CHU-029; MNHN-IU-2024-6090 • 1 ♀ 17.7 × 28.3 mm, with two cutters; same data as for preceding; CHU-030; MNHN-IU-2024-6089 • 1♂ 15.6 × 25.0 mm, right-handed; same data as for preceding; det. Austinograea sp., CHU-031; MNHN-IU-2024-6036 • 5 ♀, 1 ♀ 14.6 × 22.2 mm; with two cutters; same data as for preceding; CHU-032; MNHN-IU-2024-6091 • 1 ♂ 14.0 × 22.4 mm, right-handed; same data as for preceding; Hourdez det. Austinograea; CHU-033; MNHN-IU-2024-6032 • 1 ♂ (right-handed) 14.3 × 22.4 mm; same data as for preceding; det. Austinograea; CHU-034 writen on carapace; MNHN-IU-2024-6022 • 1 juvenile ♂ 11.8 × 18.3 mm, right-handed; same data as for preceding; Hourdez det. Austinograea sp.; MNHN-IU-2024-6034 • 1 ♂ 10.0 × 15.3 mm (without chelipeds); same data as for preceding; MNHN-IU-2018-5227. OTHER MATERIAL. — SW Pacific • 1 ♂ 14 × 21.6 mm, left-handed (gonopods detached); Manus Basin, Pacmanus, Solwara 8, PL733 - ASPI7; 3°43.819’S, 151°40.454’E; c. 1750 m; 18.V.2019; CHUBACARC 2019 cruise; MNHN-IU-2024-6086 • 1 ♂ 10.3 × 15.9 mm, right-handed; MNHN-IU-2024-6088 • 1 ♀ 22.5 × 34.6 mm; slightly right-handed, unreadable numbers writen on carapace; MNHN-IU-2024-6087. ETYMOLOGY. — The expedition name CHUBACARC 2019 cruise rhymes with one StarWars character; and the specific name chubacarc is an oblique reference to Chewbacca, the furry hero of the popular American Star Wars saga by George Lucas (Lucas film), alluding to the dense setae on the internal surface of the cheliped palm of the species. The name is used as a noun in apposition. DESCRIPTION Carapace Carapace tranversely elliptical, flat. Dorsal surface with regions indistinct, smooth, except for a few granules on frontal and suborbital regions; may have very sparse, extremely short setae, only discernible at high magnification. Front not protuding, straight or slightly convex, bluntly pointed medially (see Variations), with tiny granules. Anterolateral margin marked by rounded edge, slightly granular proximally. Posterolateral margins convergent. Posterior margin slightly concave. Proepistome sunken, very thin. Margin of epistome formed of two minutely granular, moderately concave lobes, with a median projection. Pterygostomial lobe tuberculous; pterygostomial region smooth. Subhepatic regions covered by patches of setae (see Variations). Cephalic structures Eyes, antennules and antennae recessed. Suborbital plate absent. Orbit not delimited, only an orbital area that extends as groove lateral to region containing vestigial eyestalks and antennae; outer side of orbital area tuberculated. Eyestalk not moveable, showing as fixed piece fused to floor of orbital region; no cornea, no pigment. Antennules folded horizontally. Antenna inserted in wide supraorbital notch; urinary article fixed, broad, recessed; basal article (2 + 3) cylindrical, moveable, recessed; article 4 slightly elongated, inclined; flagellum short, curved. Third maxillipeds Third maxillipeds closing buccal cavity, except anteriorly where there is a gap between them and pterygostomial lobe. Ischium long, with marked longitudinal internal groove. Merus short: external margin entirely and regularly curved, oblique, without marked angle; distal part distinctly narrower and produced; internal margin with proximal half produced as squarish lobe. Carpus inserted in notch of antero-internal margin of merus; propodus thick, developed; dactylus thick and moderately extending beyond articulaion of ischium/merus; inner margins of propodus and dactylus with some brush-like setae. Mxp3 coxa with only proximal portion visible, its lateral projection hidden by junction of thoracic sternum (sternite 4) with pterygostome. Exopod with relatively long flagellum. Chelipeds Chelipeds heteromorphic: distinctive heterochely (also in females, see below) and marked heterodonty, with two types of chelae. Major chela (crusher, see below) stout and short, with blunt tips, gaping in large males; minor chela (cutter, see below) narrower, with elongate, more pointed fingers. Ischio-basis glabrous or with potentially very small setal patch. Merus relatively short, triangular in cross section; anterior border sinuous, with strong teeth; merus glabrous in males; in contrast, in females usually each with patch of setae (see Variations). Carpus glabrous on outer part, with patch of setae only along margin articulating on propodus or more developed; surface pitted. Propodus of both chelae having outer surface of palm near base of dactylus either with two coalescing spots of variable dark colour or with a single elongated spot (actually composed of two more or less coalescing spots) and another one rounded forming a depression (see holotype Fig. 3E, G), these spots more or less distinct, tending to fade, then disappearing (see Variations, below). Spots absent in females (see below). Inner surface of both chelae and fixed finger with a depressed surface on half posterior part; on internal median part of palm, thick, wellcircumscribed patch of dense light brown setae, extending thinly along occluding margins. Crusher. Palm convex, inflated, smooth, pitted, with one or two more or less distinct spots, with depressed posterior portion on inner posterior surface. Fingers thick, not gaping at occluding margins, with blunt tips; two main, proximal and median, teeth on occluding margin of dactylus, becoming blunt in large males as holotype; a marked subproximal tooth and two smaller ones on occluding margin of fixed finger, becoming blunt, and only one remaining in large males as holotype. Median surface of thick dactylus of major male chela hollowed out by deep depression extending distally into fissure, becoming thinner and up to subdistal portion of dactylus (see Variations), this character constituting the most distinctive trait of the species. In females, such a depression absent, but more or less replaced along most part of dactylus by thin, interrupted line. In males, dark colour extending over approximately two-thirds of dactylus and most part of fixed finger. Cutter. Palm elongate, with subparallel borders; surface smooth, except for two spots of different size and shape (one as a depression, like in holotype) near base of dactylus, more or less similar to those of crusher. Both fingers not gaping at occluding margins; dactylus elongate, hollowed, with occluding margin smooth; fixed finger very thick, depressed on inner surface; occluding margin nearly straight, with two or three small teeth, decreasing in size gradually forward, becoming blunt in large individuals. In males, dark colour extending over approximately most part of both dactylus and fixed finger, but sometimes fading. In females, both chelae either similar and showing as two elongate and thin cutters or slightly heteromorphic and showing as a crusher and a cutter but without significant differences between them. Palm and fixed finger with posterior half part markedly depressed. Fingers very long, narrow, without depression on superior margin of dactylus, sometimes being replaced by thin interrupted line along most of dactylus of crusher; this line sometimes indistinct, for example in female 22.5 × 34.6 mm, MNHN-IU-2024-6087 (Fig. 7C, D), with dark (reddish) colour very marked, located only in subdistal tips of both dactylus and fixed finger. Inner surface of palm with well circumscribed thick patch of dense light brown setae, weakly extending along occluding margins; patches of setae also present on ischio-basis and proximal part of carpus and merus. Ambulatory legs P2-P5 shorter than chelipeds; P3 and P4 longest. Ischio-basis, merus and propodus with thick patches of dense setae on ventral margins (thicker on P2 and P3, weak on P5), mixed with sparse longer setae; superior border of carpus and propodus fringed with setae. Dactyli relatively stout, also with patches of short setae. Thoracic sternum Thoracic sternum with incomplete sutures 4/5-7/8, separared by short gap; suture 2/3 complete. Median line only along sternite 8. Junction of sternite 4 with pterygostome only represented by short juxtaposition. At level of antero-external portion of sternite 4 and of episternites 5, 6, 7, some setal patches in males, denser in young adult females, and, in larger females, becoming well circumscribed patches with decreasing size from front to back. Press-button of locking mechanism very acute, close to suture 5/6. Pleon Male pleon of six free somites and telson, regularly triangular; pleonal somites 1, 2 dorsally exposed; pleonal somite 3 widest; pleonal somite 6 longest; telson triangular, slightly rounded distally. On posterior angles of somite 6, a deep socket delineated by raised, thick margin. Penis and gonopods Penis emerging from