taxonID	type	description	language	source
503B2128FFFD65779A6F93EAFBD38707.taxon	materials_examined	Western Pacific • 1 ♂, 1 ♀; western Pacific: TUIM 06 MV cruise; dive PL 142, slurp 1, Lau Basin, Cam Tow; 2719 m; 19. V. 2005; 20 ° 19 ’ S, 176 ° 08 ’ W; ZRC 2024.0727, ex MNHN-IU- 2022 - 4049.	en	Guinot, Danièle, Ng, Peter K. L. (2025): Kallograea kulolasi n. gen., n. sp. and K. jolliveti (Guinot & Segonzac, 2018) from the hydrothermal Kulo Lasi Volcano Caldera, West Pacific; and a reappraisal of Austinograea Hessler & Martin, 1989 and Gandalfus McLay, 2007 (Decapoda, Brachyura, Bythograeoidea). Zoosystema 47 (33): 773-797, DOI: 10.5252/zoosystema2025v47a33, URL: https://sciencepress.mnhn.fr/sites/default/files/articles/pdf/zoosystema2025v47a33_.pdf
503B2128FFFD65779A6F9348FCB086AD.taxon	materials_examined	Paratypes. Western Pacific • 1 ♂ (21.4 × 34.3 mm); dive 232, Tu’i Malila site; Lau Back-Arc Basin; 1891 m; 11. IX. 2006; 21 ° 59.34 ’ S, 176 ° 34.09 ’ W: MNHN-IU- 2016 - 10740 • 1 ♀; dive 427, ABE site, Lau Back-Arc Basin; 2130 m; 7. IX. 2009; 20 ° 45.65 ’ S, 176 ° 11.45 ’ W; MNHNIU- 2016 - 10744.	en	Guinot, Danièle, Ng, Peter K. L. (2025): Kallograea kulolasi n. gen., n. sp. and K. jolliveti (Guinot & Segonzac, 2018) from the hydrothermal Kulo Lasi Volcano Caldera, West Pacific; and a reappraisal of Austinograea Hessler & Martin, 1989 and Gandalfus McLay, 2007 (Decapoda, Brachyura, Bythograeoidea). Zoosystema 47 (33): 773-797, DOI: 10.5252/zoosystema2025v47a33, URL: https://sciencepress.mnhn.fr/sites/default/files/articles/pdf/zoosystema2025v47a33_.pdf
503B2128FFFD65779A6F94CFFB61860F.taxon	materials_examined	Paratypes. Western North Pacific • 1 ♂ (21.6 × 34.2 mm), 1 ♀ (22.5 × 35.3 mm), 1 small ♂ (15.2 × 23.8 mm); dive 1845; Alice Springs vent field; 3640 m; 6. V. 1987; 18 ° 12.599 ’ N, 144 ° 42.431 ’ E; MNHN-IU- 2008 - 11121 (= MNHN-B 20910).	en	Guinot, Danièle, Ng, Peter K. L. (2025): Kallograea kulolasi n. gen., n. sp. and K. jolliveti (Guinot & Segonzac, 2018) from the hydrothermal Kulo Lasi Volcano Caldera, West Pacific; and a reappraisal of Austinograea Hessler & Martin, 1989 and Gandalfus McLay, 2007 (Decapoda, Brachyura, Bythograeoidea). Zoosystema 47 (33): 773-797, DOI: 10.5252/zoosystema2025v47a33, URL: https://sciencepress.mnhn.fr/sites/default/files/articles/pdf/zoosystema2025v47a33_.pdf
503B2128FFFD65779A6F9240FB0C84DF.taxon	materials_examined	Western Pacific • holotype ♂ (15.5 × 24.3 mm); stn TAN 0107 / 128; Rumble III; 35 ° 44.22 - 44.04 ’ S, 178 ° 29.72 - 29.63 ’ E; 270 - 239 m; 21. V. 2001; NIWA 27855 • 1 paratype ♂ (21.3 × 33.5 mm); Macauley Caldera, Kermadec Islands; 337 m; 12. IV. 2005; 30 ° 12.78 ’ S, 181 ° 33.04 ’ E; NIWA 18017 • 1 paratype ♂ (22.9 × 36.4 mm); Brothers Seamount, dive KOK 0506 / 32; 1647 m; 2. V. 2005; 34 ° 51.70 ’ S, 179 ° 3.58 ’ E; NIWA 18019 • 1 ♂ (22.6 × 36.7 mm) [coated with a brown ferric deposits, slightly damaged], 1 ♂ (11.6 × 18 mm); Kermadec Islands, Macauley Caldera, stn KOK 0506 / 22; 337 m; 12. IV. 2005; 30 ° 12.78 ’ S, 181 ° 33.04 ’ E; NIWA 18018 • 1 ♂ (entirely white) (18.8 × 29.0 mm); stn TAN 1213 / 59; 405.0 - 408 m; 26. X. 2012; NIWA 86453 • 1 ♂, 6 ♀ [1 ♀ 10.4 × 14.3 mm, ZRC 2024.0726]; Haungaroa Caldera; HYDROTHERMADEC cruise; dive 413; stn 026; 707 m; 31. XII. 2016; 32 ° 37.04 ’ S, 179 ° 37.51 ’ E; MNHNIU- 2024 - 6553 (ex SH 162 - 065).	en	Guinot, Danièle, Ng, Peter K. L. (2025): Kallograea kulolasi n. gen., n. sp. and K. jolliveti (Guinot & Segonzac, 2018) from the hydrothermal Kulo Lasi Volcano Caldera, West Pacific; and a reappraisal of Austinograea Hessler & Martin, 1989 and Gandalfus McLay, 2007 (Decapoda, Brachyura, Bythograeoidea). Zoosystema 47 (33): 773-797, DOI: 10.5252/zoosystema2025v47a33, URL: https://sciencepress.mnhn.fr/sites/default/files/articles/pdf/zoosystema2025v47a33_.pdf
503B2128FFFD65779A6F919BFA6085FA.taxon	materials_examined	Western Pacific • 1 ♀ (28.2 × 42.2 mm); off central Japan, Philippine Sea Plate, Kaikata Seamount, Shinkai 2000, dive # 1014; 26 ° 42.35 ’ N, 141 ° 04.67 ’ E; 448 m deep; 18. V. 1998; MNHN-IU- 2024 - 6053 (= MNHN-B 28759) (ex JAMSTEC) • 1 ♀ (43.4 × 28.4 mm); same data; MNHN-IU- 2024 - 6054 (= MNHN-B 28759) (ex JAMSTEC) • 1 ♂ (20.5 × 29.9 mm); same data; MNHN-IU- 2024 - 6055 (= MNHN-B 28759) (ex JAMSTEC) • paratype ♂ (20.5 × 29.9 mm); off central Japan, Philippine Sea Plate, Myojin Knoll, Shinkai 2000, dive # 1007, 32 ° 06.19 ’ N, 139 ° 52.04 ’ E, 1263 m deep, 5. V. 1998; MNHN-IU- 2008 - 11865 (= MNHN-B 28419).	en	Guinot, Danièle, Ng, Peter K. L. (2025): Kallograea kulolasi n. gen., n. sp. and K. jolliveti (Guinot & Segonzac, 2018) from the hydrothermal Kulo Lasi Volcano Caldera, West Pacific; and a reappraisal of Austinograea Hessler & Martin, 1989 and Gandalfus McLay, 2007 (Decapoda, Brachyura, Bythograeoidea). Zoosystema 47 (33): 773-797, DOI: 10.5252/zoosystema2025v47a33, URL: https://sciencepress.mnhn.fr/sites/default/files/articles/pdf/zoosystema2025v47a33_.pdf
503B2128FFFC6576982596E8FEC88470.taxon	description	urn: lsid: zoobank. org: act: 4 AA 24 DD 0 - 6035 - 4 ED 5 - 8075 - 54 ECFABE 95 E 6	en	Guinot, Danièle, Ng, Peter K. L. (2025): Kallograea kulolasi n. gen., n. sp. and K. jolliveti (Guinot & Segonzac, 2018) from the hydrothermal Kulo Lasi Volcano Caldera, West Pacific; and a reappraisal of Austinograea Hessler & Martin, 1989 and Gandalfus McLay, 2007 (Decapoda, Brachyura, Bythograeoidea). Zoosystema 47 (33): 773-797, DOI: 10.5252/zoosystema2025v47a33, URL: https://sciencepress.mnhn.fr/sites/default/files/articles/pdf/zoosystema2025v47a33_.pdf
503B2128FFFC6576982596E8FEC88470.taxon	type_taxon	TYPE SPECIES. — Kallograea kulolasi n. sp., by present designation.	en	Guinot, Danièle, Ng, Peter K. L. (2025): Kallograea kulolasi n. gen., n. sp. and K. jolliveti (Guinot & Segonzac, 2018) from the hydrothermal Kulo Lasi Volcano Caldera, West Pacific; and a reappraisal of Austinograea Hessler & Martin, 1989 and Gandalfus McLay, 2007 (Decapoda, Brachyura, Bythograeoidea). Zoosystema 47 (33): 773-797, DOI: 10.5252/zoosystema2025v47a33, URL: https://sciencepress.mnhn.fr/sites/default/files/articles/pdf/zoosystema2025v47a33_.pdf
503B2128FFFC6576982596E8FEC88470.taxon	etymology	ETYMOLOGY. — The name is derived from the Greek “ kallo ” for “ beautiful ”, and the name for marine crabs “ graea ” (cf. Liddell & Scott 1940); alluding to the slender and delicate chelipeds of the two constituent species. The gender is feminine.	en	Guinot, Danièle, Ng, Peter K. L. (2025): Kallograea kulolasi n. gen., n. sp. and K. jolliveti (Guinot & Segonzac, 2018) from the hydrothermal Kulo Lasi Volcano Caldera, West Pacific; and a reappraisal of Austinograea Hessler & Martin, 1989 and Gandalfus McLay, 2007 (Decapoda, Brachyura, Bythograeoidea). Zoosystema 47 (33): 773-797, DOI: 10.5252/zoosystema2025v47a33, URL: https://sciencepress.mnhn.fr/sites/default/files/articles/pdf/zoosystema2025v47a33_.pdf
503B2128FFFC6576982596E8FEC88470.taxon	diagnosis	DIAGNOSIS. — Carapace transversely elliptical. Dorsal surface of carapace almost flat; regions indistinct. Eyestalk absent, podophthalmite fused to floor of orbital region; cornea absent, no visible pigment. Antennules, antennae recessed under front. Mxp 3 ischium distinctly elongate; merus subtriangular, distally produced. Adult male chelipeds prominently elongate; merus long, slender; palm elongated (especially in K. kulolasi n. sp.), with setal patch either exclusively on inner surface and between fingers of both chelipeds (K. jolliveti n. comb.) or on either side of superior margin (including the superior margin itself), thus on both sides of palm and extending between fingers (K. kulolasi n. sp.); crusher with thick blunt-tipped fingers. No spot on anterior portion of palm near base of dactylus, but coloured spot at base of fixed finger (K. jolliveti n. comb.). Adult male ambulatory legs slender, elongate, especially merus, propodus. Thoracic sternum short, wide. Male sternopleonal cavity gently concave, relatively wide distally, but without obvious depression for G 1 tips. Longitudinal median line along entire male and female thoracic sternite 8, deep. G 1 almost straight, obliquely directed, not crossing each other along distal parts. G 2 either rather long, with the flagellum slightly longer than basal part, or shorter and with a small flagellum. Vulvae relatively large, occupying most of surface of thoracic sternite 6.	en	Guinot, Danièle, Ng, Peter K. L. (2025): Kallograea kulolasi n. gen., n. sp. and K. jolliveti (Guinot & Segonzac, 2018) from the hydrothermal Kulo Lasi Volcano Caldera, West Pacific; and a reappraisal of Austinograea Hessler & Martin, 1989 and Gandalfus McLay, 2007 (Decapoda, Brachyura, Bythograeoidea). Zoosystema 47 (33): 773-797, DOI: 10.5252/zoosystema2025v47a33, URL: https://sciencepress.mnhn.fr/sites/default/files/articles/pdf/zoosystema2025v47a33_.pdf
503B2128FFFC6576982596E8FEC88470.taxon	discussion	REMARK The genera closest to Kallograea n. gen. are Austinograea Hessler & Martin, 1989 and Gandalfus McLay, 2007, for which we deem necessary to give detailed illustrations of the species for comparisons of these two genera with the new genus established here; see below.	en	Guinot, Danièle, Ng, Peter K. L. (2025): Kallograea kulolasi n. gen., n. sp. and K. jolliveti (Guinot & Segonzac, 2018) from the hydrothermal Kulo Lasi Volcano Caldera, West Pacific; and a reappraisal of Austinograea Hessler & Martin, 1989 and Gandalfus McLay, 2007 (Decapoda, Brachyura, Bythograeoidea). Zoosystema 47 (33): 773-797, DOI: 10.5252/zoosystema2025v47a33, URL: https://sciencepress.mnhn.fr/sites/default/files/articles/pdf/zoosystema2025v47a33_.pdf
503B2128FFFC657D987F91EFFB5C8193.taxon	description	(Figs 4 - 7) urn: lsid: zoobank. org: act: 8 E 69 D 842 - 1647 - 45 A 5 - 8 EB 9 - AC 968353 F 769	en	Guinot, Danièle, Ng, Peter K. L. (2025): Kallograea kulolasi n. gen., n. sp. and K. jolliveti (Guinot & Segonzac, 2018) from the hydrothermal Kulo Lasi Volcano Caldera, West Pacific; and a reappraisal of Austinograea Hessler & Martin, 1989 and Gandalfus McLay, 2007 (Decapoda, Brachyura, Bythograeoidea). Zoosystema 47 (33): 773-797, DOI: 10.5252/zoosystema2025v47a33, URL: https://sciencepress.mnhn.fr/sites/default/files/articles/pdf/zoosystema2025v47a33_.pdf
503B2128FFFC657D987F91EFFB5C8193.taxon	materials_examined	TYPE MATERIAL. — Holotype. Western Pacific • ♂ (right-handed) 7.3 × 12.7 mm; CHUBACARC 2019 cruise, Leg 1; Futuna Volcanic Arc, Kulo Lasi Caldera; 15 ° 10.0692 ’ S, 14 ° 42.9563, 177 ° 28.4632 ’, 177 ° 00.5768 ’ W (latitude minimum / maximum and longitude minimum / maximum, respectively); PL 729 - GBT 1; 1472 m; MNHNIU- 2024 - 6067. Paratypes. Western Pacific • 1 ♂ (right-handed) 7.5 × 12.0 mm; same data as holotype; MNHN-IU- 2024 - 6084 • 1 ♂ 9.7 × 15.4 mm (without chelipeds); MNHN-IU- 2024 - 6035 [CHU 036] • 1 ♀ 8.1 × 12.6 mm (with detached chelipeds in tube); MNHN-IU- 2024 - 6033 • 1 ♂ 9.6 × 16.4 mm; MNHN-IU- 2024 - 6552 [CHU 035] • 1 ♂ (left-handed) 8.8 × 14.1 mm; ZRC 2024.0724 (ex MNHNIU- 2024 - 6085). TYPE LOCALITY. — Kulo Lasi Caldera, on periphery.	en	Guinot, Danièle, Ng, Peter K. L. (2025): Kallograea kulolasi n. gen., n. sp. and K. jolliveti (Guinot & Segonzac, 2018) from the hydrothermal Kulo Lasi Volcano Caldera, West Pacific; and a reappraisal of Austinograea Hessler & Martin, 1989 and Gandalfus McLay, 2007 (Decapoda, Brachyura, Bythograeoidea). Zoosystema 47 (33): 773-797, DOI: 10.5252/zoosystema2025v47a33, URL: https://sciencepress.mnhn.fr/sites/default/files/articles/pdf/zoosystema2025v47a33_.pdf
503B2128FFFC657D987F91EFFB5C8193.taxon	etymology	ETYMOLOGY. — Named after the Kulo Lasi Volcano where the species was discovered. Kulo lasi is a common name meaning ‘ big cauldron’ in Futunian. Used as a noun in apposition.	en	Guinot, Danièle, Ng, Peter K. L. (2025): Kallograea kulolasi n. gen., n. sp. and K. jolliveti (Guinot & Segonzac, 2018) from the hydrothermal Kulo Lasi Volcano Caldera, West Pacific; and a reappraisal of Austinograea Hessler & Martin, 1989 and Gandalfus McLay, 2007 (Decapoda, Brachyura, Bythograeoidea). Zoosystema 47 (33): 773-797, DOI: 10.5252/zoosystema2025v47a33, URL: https://sciencepress.mnhn.fr/sites/default/files/articles/pdf/zoosystema2025v47a33_.pdf
503B2128FFFC657D987F91EFFB5C8193.taxon	description	DESCRIPTION Carapace Small size (carapace width 12.0 - 16.4 mm). Carapace elliptical, very short, very elongated transversely, width-to-length ratio 1.59 - 1.74, flat; regions indistinct (Figs 4 A, C; 5 A; 6 A). Dorsal surface entirely smooth, glabrous (Figs 4 A, C; 5 A; 6 A). Anterolateral margin regularly rounded, with minute, barely discernible granules; supra-orbital margin with more obvious granules (Figs 4 A, C, E; 5 A, C; 6 A, E). Posterolateral margins convergent posteriad; posterior margin slightly concave (Figs 4 A, C; 5 A; 6 A). Subhepatic regions entirely glabrous (Figs 4 E; 5 B, C; 6 E). Front broad, not protruded, practically straight, not emarginate medially, barely pointed medially, with two indistinct lobes; margin without discernible granules (Figs 4 A, C, E; 5 A; 6 A, E). Infra-orbital region with scattered small granules (Figs 4 E; 6 E). Eyes, antennules, antennae recessed below front (Figs 4 E; 6 E). Orbit not delimited; orbital region extending as groove, lateral to area with vestigial eyestalks and antennae (Figs 4 E; 5 A, C; 6 E). Eyestalk absent; podophthalmite barely visible, as small fixed piece fused to floor of orbital region; cornea absent but a tiny dark pigment barely visible (Figs 4 E; 5 A, C; 6 E). Antennules folded horizontally (Figs 4 E; 5 C; 6 E). Antenna very small; urinary article fixed, recessed; basal article (2 + 3) cylindrical, moveable; article 4 slightly elongated, inclined; flagellum not long. Proepistome very thin (Figs 4 E; 5 C, E; 6 E). Posterior margin of epistome wide, with lateral margins distinctly concave, median projection obtusely triangular (Figs 4 E; 6 E). Pterygostomial lobe with small granules; pterygostomial region smooth (except minute granules along lateral line), glabrous, except along lateral line (Figs 4 E; 5 B, C; 6 E). Mxp 3 Mxp 3 completely closing buccal cavity, on all parts, especially between antero-external margin of merus and pterygostomial lobe. Ischium long, external margin oblique; longitudinal internal groove weak. Merus: external margin proximally straight, then obliquely directed; distal and external margins almost touching pterygostomial lobe; merus distal part markedly narrow, produced; internal margin bluntly angled medially. Carpus inserted on distal part of antero-internal margin of merus; propodus thick, short; dactylus long, reaching about three-quarters length of ischium; inner margins of propodus and dactylus with brush-like setae. Mxp 3 coxa with only proximal portion visible, lateral projection hidden by junction of thoracic sternum (sternite 4) with pterygostome. Exopod thick, longer than endopod ischium (Figs 4 D, E; 5 B; 6 E). Male chelipeds Male chelipeds elongate, not clearly heteromorphic (weak heterochely in females, see below) (Figs 4 A-C; 5 C-F). Merus very long, slender, extending far beyond margin of carapace, subcylindrical, triangular in cross section, anterior border straight (without expansion), with regularly spaced small granules. Carpus covered with thick patches of thin soft setae on whole external surface; propodus of both chelipeds very long, with superior margin covered by thick patches of thin soft setae, appearing as a white down-like pubescence (Fig. 4 C) (more developed on major chela), partially extending on both outer and inner parts of palm (more on inner part) and extending partially to basal part of dactylus. Fingers distinctly shorter than palm, with dark colour extending along distal third- or quarter-length; no setae along occluding margins. No obvious spot at base of propodus. Dark pigmentation on fingers not extending to palm, confined to tips in males (as in females) (Fig. 5 C-E). In right-handed males (like holotype), major cheliped (crusher) stouter, slightly shorter than minor chela (cutter); both fingers very thick, distinctly blunt-tipped, weakly gaping; dactylus with small tooth, then molariform tooth on occluding margin; fixed finger thick, with some small denticles on occluding margin; dark colour extending dorsally on only distal part of fingers. Minor cheliped (cutter) with finger tips pointed. Merus as in major chela; palm rather long, outer surface slightly convex, smooth; both fingers not gaping at occluding margin, both tips curved, crossed; dactylus elongate, with occluding margin lined with some minute proximal teeth; fixed finger very thick, with thin extension bearing nearly straight occluding margin, with some small proximal teeth (Figs 4 A, B; 5 C, D). In left-handed male (e. g., ZRC 2024.0724, ex MNHNIU- 2024 - 6085), chelae less developed; fingers of major chela much stouter than pointed fingers of minor chela; both fingers relatively thinner, only very weakly gaping, less blunt-tipped, slightly curved at tip; minor chela elongated, with less dense patch of thin soft setae on superior margin; fixed finger regularly teethed (medially granular in left-handed males) (Fig. 5 E, F). Female chelipeds Female chelipeds (♀ 8.1 × 12.6 mm mm, MNHNIU- 2024 - 6033) not as developed as those of males, with merus distinctly shorter and narrower than in males (Fig. 6 A, B). Chelae slightly heteromorphic, not blunt-tipped, with both fingers not gaping, crossing at tips; major chela only a little stouter as minor chela. As in males, patches of thin soft setae, appearing as down-like pubescence, on superior margin of carpus, propodus, extending on both outer and inner part of palm. Dark pigmentation of fingers in most part confined to tips (as in males) (Fig. 6 C, D). Ambulatory legs P 2 - P 5, in particular meri, distinctly long, slender. P 2 much shorter than chelipeds; P 3, P 4 longest. Merus of P 2 - P 4 smooth, without patches of setae, only with a few sparse setae; carpus, propodus and dactylus of P 2 - P 5 with sparse setae on ventral margins (Figs 4 A-C; 6 A, B). Thoracic sternum Thoracic sternum very wide, short, extending laterally, elliptical; suture 2 / 3 complete; sutures 4 / 5 - 7 / 8 incomplete; sutures 6 / 7 and 7 / 8 medially less calcified (Fig. 4 D, F). Junction of sternite 4 with pterygostome represented by only short juxtaposition, without patch of setae. Median line at level of sternite 8 in both sexes, reaching to junction with sternite 7 (Fig. 4 F). In males, press-button of locking mechanism acute, on sternite 5 abutting against suture 5 / 6 (Fig. 4 F). Entirely smooth, glabrous in both sexes (Figs 4 D, F; 6 B, F). Pleon Both sexes with six free somites and telson. Male pleon rather wide, regularly triangular; pleonal somite 3 widest; pleonal somite 6 longest; telson very short, bluntly semicircular (Fig. 4 B, D). Press-button on narrow portion of sternite 5, absent in females (Fig. 4 F). Female pleon almost round, covering most of thoracic sternites; telson semicircular (Fig. 6 B). Gonopods G 1 almost straight, directed obliquely into sternopleonal cavity, never contiguous, and even distant throughout their entire length, including their tips which are apart, not recessed in medial depression at end of sternopleonal cavity. Only some setae along mid distal part (Figs 4 G; 7 A-D). G 2 relatively long, flagellum slightly longer than basal part, curved, blade-like, distal part slightly dilated (Figs 4 H; 7 E, F). Vulvae Vulvae distant from each other, subhemispherical; close to but separate from thoracic sternal suture 5 / 6, occupying 2 / 3 of surface of sternite 6 (Fig. 6 F).	en	Guinot, Danièle, Ng, Peter K. L. (2025): Kallograea kulolasi n. gen., n. sp. and K. jolliveti (Guinot & Segonzac, 2018) from the hydrothermal Kulo Lasi Volcano Caldera, West Pacific; and a reappraisal of Austinograea Hessler & Martin, 1989 and Gandalfus McLay, 2007 (Decapoda, Brachyura, Bythograeoidea). Zoosystema 47 (33): 773-797, DOI: 10.5252/zoosystema2025v47a33, URL: https://sciencepress.mnhn.fr/sites/default/files/articles/pdf/zoosystema2025v47a33_.pdf
503B2128FFFC657D987F91EFFB5C8193.taxon	discussion	REMARKS Five males and one female of Kallograea kulolasi n. gen., n. sp., all small specimens, have been collected by the French CHUBACARC 2019 cruise on the periphery of the caldera of Kulo Lasi Volcano, through a unique dive in the north sector (Figs 2; 3). Immediately suspected of being new by Stéphane Hourdez (pers. comm.), they are here confirmed to represent an undescribed species. Kallograea kulolasi n. gen., n. sp. is a small-sized species, however, with well-developed gonopods and vulvae. It is also the smallest bythograeid known in the world. The smallest bythograeid previously was Bythograea microps Saint Laurent, 1984 (Saint Laurent 1984: 356) from the East Pacific Rise (between 21 ° N and 9 ° 50 ’ N), which is indicated as having a maximum carapace width 40 mm according to Guinot & Segonzac (2006 b: 468), but it seems that this size may be overestimated: the male collected during the Hot 96 mission measuring 13 × 24 mm likely represents the largest B. microps known to date (Guinot & Segonzac 1997: 139; Guinot & Hurtado 2003: 437). Kallograea kulolasi n. gen., n. sp. is distinctly smaller, with specimens measuring 12 mm in carapace width already mature (e. g., MNHN-IU- 2024 - 6084). Kallograea kulolasi n. gen., n. sp. is characterised by a flat carapace, the males possessing distinctly elongate chelipeds, with especially blunt fingers on the major chela, and a prominent setal patch on the propodus that appears as a white down-like pubescence on the superior margin of the cheliped palm and extending on the inner and outer surfaces. This pubescence is best observed in water or ethanol, as the setae collapse and clump together when the specimen is studied dried (compare Fig. 4 C with Fig. 5 E, F). Since in most Austinograea species the setal patch is exclusively located on the inside of the palm, its presence on either side of the upper palm margin is a unique feature of K. kulolasi n. gen., n. sp. A setal patch is also present over the entire external surface of the carpus, which is not found in other bythograeoids, which have a glabrous carpus instead. The markedly thick and blunt-tipped fingers of the crusher cheliped is also a remarkable character of K. kulolasi n. gen., n. sp. The condition of these finger tips is unusual and perhaps functions similarly to the spoon-tipped fingers of other crabs. As indicated by Davie et al. (2015), not much is known about the precise function of spoon-tipped fingers, but they seem to be generally used for feeding on detritus, scooping up mucus from corals or picking up other soft foods, scraping off encrusting algae, effective gripping of filamentous algae, or scraping epilithic algae off coral rock. The rounded finger tips of the major chelae of K. kulolasi n. gen., n. sp. may be adapted for harvesting the filamentous bacterial matter in its habitat. The palm and fingers of male adult chelipeds appear very heavy relative to the long and slender merus, in which the apodemes and attached muscles have little room, and together with the flat carapace, gives the crab a very distinctive appearance. Male Kallograea kulolasi n. gen., n. sp. clearly prioritises investing in strong chelipeds but in females, the chelipeds are proportionately shorter and the chelae are less strongly developed. This marked sexual dimorphism suggests the male chelipeds may have a role in reproductive selection.	en	Guinot, Danièle, Ng, Peter K. L. (2025): Kallograea kulolasi n. gen., n. sp. and K. jolliveti (Guinot & Segonzac, 2018) from the hydrothermal Kulo Lasi Volcano Caldera, West Pacific; and a reappraisal of Austinograea Hessler & Martin, 1989 and Gandalfus McLay, 2007 (Decapoda, Brachyura, Bythograeoidea). Zoosystema 47 (33): 773-797, DOI: 10.5252/zoosystema2025v47a33, URL: https://sciencepress.mnhn.fr/sites/default/files/articles/pdf/zoosystema2025v47a33_.pdf
503B2128FFFC657D987F91EFFB5C8193.taxon	distribution	DISTRIBUTION Known only from the Futuna volcanic Arc, on the periphery of the Kulo Lasi Caldera.	en	Guinot, Danièle, Ng, Peter K. L. (2025): Kallograea kulolasi n. gen., n. sp. and K. jolliveti (Guinot & Segonzac, 2018) from the hydrothermal Kulo Lasi Volcano Caldera, West Pacific; and a reappraisal of Austinograea Hessler & Martin, 1989 and Gandalfus McLay, 2007 (Decapoda, Brachyura, Bythograeoidea). Zoosystema 47 (33): 773-797, DOI: 10.5252/zoosystema2025v47a33, URL: https://sciencepress.mnhn.fr/sites/default/files/articles/pdf/zoosystema2025v47a33_.pdf
503B2128FFF765699A7B948AFACF8751.taxon	description	(Figs 8; 9)	en	Guinot, Danièle, Ng, Peter K. L. (2025): Kallograea kulolasi n. gen., n. sp. and K. jolliveti (Guinot & Segonzac, 2018) from the hydrothermal Kulo Lasi Volcano Caldera, West Pacific; and a reappraisal of Austinograea Hessler & Martin, 1989 and Gandalfus McLay, 2007 (Decapoda, Brachyura, Bythograeoidea). Zoosystema 47 (33): 773-797, DOI: 10.5252/zoosystema2025v47a33, URL: https://sciencepress.mnhn.fr/sites/default/files/articles/pdf/zoosystema2025v47a33_.pdf
503B2128FFF765699A7B948AFACF8751.taxon	materials_examined	MATERIAL EXAMINED. — Holotype. Western Pacific • ♂ 12.8 × 20.0 mm (right-handed); North Fiji Basin; STARMER II cruise, dive 18 (PL 18); Mussel Valley site; 18 ° 50 ’ S, 173 ° 29 ’ E; 2750 m; 3. VII. 1989; MNHN-IU- 2016 - 10769. Paratypes. Western Pacific • 1 ♂ (slightly right-handed) 14.7 × 25.4 mm, 1 ♀ 12.4 × 21.6 mm; same data as for holotype; MNHNIU- 2016 - 10770. OTHER MATERIAL. — Western Pacific • 1 ♀ 13.6 × 22.0 mm (left-handed); Lau Back-Arc Basin; MGLN 07 MV cruise, dive 237; ABE site; 20 ° 45.65 ’ S, 176 ° 11.45 ’ E; 2130 m; 25. IX. 2006; MNHNIU- 2016 - 10751. NEW MATERIAL. — Western Pacific • 1 ♂ 14.3 × 22.7 mm (slightly left-handed), Futuna 1 cruise, Kulo Lasi, PL 1776 - 4 – aspi 4; 14 ° 56.35 ’ S, 177 ° 15.57 W; 1406 m; 12. IX. 2010; L. Menot coll.; R / V Atalante; ROV Nautile; M. Segonzac 06.2011 det. Austinograea sp.; ZRC 2024.0725 (MNHN-IU- 2009 - 4045) • 2 ♂ 8.0 × 13.4 mm, 9.0 × 12.4 mm, 1 ♀ 8.4 × 13.8 mm (most of legs and chelipeds detached), Futuna 3 cruise, PL 06 – aspi 04; MNHN-IU- 2024 - 6075 • 1 ♀ 13.5 × 20.0 mm, CHUBACARC cruise, PL 734 - GBT 2, Manus Basin, Pac Manus, Roman’s Ruins; 03 ° 43 649, 151 ° 40 861; 1725 m; MNHN-IU- 2024 - 6026 [CHU 511] • 1 ♂ 12.2 × 16.8 mm (right-handed); CHUBACARC cruise, PL 733 - GBT 5; Manus Basin, Pac Manus, Fenway; MNHN-IU- 2024 - 6551.	en	Guinot, Danièle, Ng, Peter K. L. (2025): Kallograea kulolasi n. gen., n. sp. and K. jolliveti (Guinot & Segonzac, 2018) from the hydrothermal Kulo Lasi Volcano Caldera, West Pacific; and a reappraisal of Austinograea Hessler & Martin, 1989 and Gandalfus McLay, 2007 (Decapoda, Brachyura, Bythograeoidea). Zoosystema 47 (33): 773-797, DOI: 10.5252/zoosystema2025v47a33, URL: https://sciencepress.mnhn.fr/sites/default/files/articles/pdf/zoosystema2025v47a33_.pdf
503B2128FFF765699A7B948AFACF8751.taxon	discussion	REMARKS See description by Guinot & Segonzac (2018: 89, figs 9 AH; 10 A-E; 11 A-E) and remarks on K. kulolasi n. gen., n. sp. In Kallograea jolliveti n. comb., the pigmented spot near the base of the fixed finger and more or less in continuity with the dark colour of the fixed finger, and present on both chelae in both sexes (Figs 8 C; 9 C, D), recalls the distinctly coloured, more or less purplish, oval spot of Bythograea microps Saint Laurent, 1984, located practically in the same place and also present in both sexes (Saint Laurent 1984: pl. 1 F; Guinot & Segonzac 2006 b: fig. 5). In addition to the similarly coloured spot on the cheliped palm, these two species are both relatively small; but, whereas B. microps shows only a drastic reduction of the eyestalks (Saint Laurent 1984: 386; 1988; Guinot & Segonzac 2006 b: fig. 2), K. jolliveti n. comb. is entirely blind: the eyestalks are absent, the podophthalmite is fused to the floor of the orbital region, and the cornea is absent, without any visible pigment (Fig. 8 B).	en	Guinot, Danièle, Ng, Peter K. L. (2025): Kallograea kulolasi n. gen., n. sp. and K. jolliveti (Guinot & Segonzac, 2018) from the hydrothermal Kulo Lasi Volcano Caldera, West Pacific; and a reappraisal of Austinograea Hessler & Martin, 1989 and Gandalfus McLay, 2007 (Decapoda, Brachyura, Bythograeoidea). Zoosystema 47 (33): 773-797, DOI: 10.5252/zoosystema2025v47a33, URL: https://sciencepress.mnhn.fr/sites/default/files/articles/pdf/zoosystema2025v47a33_.pdf
503B2128FFF765699A7B948AFACF8751.taxon	distribution	DISTRIBUTION Kallograea jolliveti n. comb. has a wide distribution in the western Pacific: initially, North Fiji and Lau Basins, now Kulo Lasi Volcano and Manus Basin.	en	Guinot, Danièle, Ng, Peter K. L. (2025): Kallograea kulolasi n. gen., n. sp. and K. jolliveti (Guinot & Segonzac, 2018) from the hydrothermal Kulo Lasi Volcano Caldera, West Pacific; and a reappraisal of Austinograea Hessler & Martin, 1989 and Gandalfus McLay, 2007 (Decapoda, Brachyura, Bythograeoidea). Zoosystema 47 (33): 773-797, DOI: 10.5252/zoosystema2025v47a33, URL: https://sciencepress.mnhn.fr/sites/default/files/articles/pdf/zoosystema2025v47a33_.pdf
503B2128FFF765699A7B948AFACF8751.taxon	diagnosis	COMPARISON BETWEEN KALLOGRAEA KULOLASI N. GEN., N. SP. (Figs 4 - 7) AND K. JOLLIVETI N. COMB. (Figs 8, 9) Kallograea kulolasi n. gen., n. sp. can easily be distinguished from K. jolliveti n. comb. by the suborbital region being glabrous or almost so (Figs 4 E; 5 A; 6 E) (vs densely setose in K. jolliveti n. comb.; Fig. 8 B); median lobe of the posterior epistomial margin being obtusely triangular, with the lateral margins concave (Figs 4 E; 5 C; 6 E) (vs median lobe more acutely triangular with lateral margins gently sinuous to almost straight in K. jolliveti n. comb.; Fig. 8 B); the mxp 3 completely closes the buccal cavity across the anterior part, with the distal and external margins of the merus almost touching the pterygostomial lobe (Figs 4 E; 5 C; 6 E) (vs distinct gap between the distal and external margins of the merus and the pterygostomial lobe in K. jolliveti n. comb.; Fig. 8 B); the P 2 - P 5, in particular the meri, are distinctly longer and more slender (Figs 4 A-C; 6 A, B) (vs shorter and stouter in K. jolliveti n. comb.; Figs 8 A; 9 A); the ventral margins of P 2 – P 4 have only scattered setae (vs with dense tomentum in K. jolliveti n. comb.); in both sexes, the dorsal margin of palm as well as the upper third or half of the outer surface (including the superior margin) and the upper third of the inner surface of adult male palm are densely setose but the rest of the inner surface is glabrous (Figs 4 A-C; 5 C-F; 6 A-D) (vs dorsal and outer surfaces glabrous although the inner surface is densely setose in K. jolliveti n. comb.; Figs 8 A, C-F; 9 A, C-E); there is no spot at the base of the male pollex (Figs 5 C, E; 6 C) (vs with a visible pale-coloured spot in K. jolliveti n. comb.; Figs 8 C, D; 9, D); the fingers of the male chela are relatively shorter than the palm, with the pigmentation extending along the distal third or quarter (Figs 5 C-F; 6 C, D) (vs the fingers of the male chela are as long as the palm, with the pigmentation extending along the distal half in K. jolliveti n. comb.; Figs 8 A, C-F; 9 A, C-E); the male thoracic sternum is proportionately wider, in relation with the short body of the species (Fig. 4 B, D, F) (vs thoracic sternum less wide in K. jolliveti n. comb.; Figs 8 G; 9 G); the longitudinal median line on sternite 8 is relatively deeper (Figs 4 F; 6 F) (vs median line less deep in K. jolliveti n. comb.; Figs 8 H; 9 G); the male pleon is distinctly wider, with the telson semicircular in form (Fig. 4 B, D) (vs pleon less wide with the telson more triangular in K. jolliveti n. comb.; Fig. 8 G); the G 1 is more strongly curved outwards (Figs 4 G; 7 A, B) (vs distinctly straighter in K. jolliveti n. comb.; Fig. 8 I, J); the G 2 is proportionately much longer in K. kulolasi n. gen., n. sp., with the flagellum slightly longer than basal part (Figs 4 H; 7 E) (vs G 2 relatively shorter, with a small flagellum in K. jolliveti; Fig. 8 K); and the medially positioned subhemispherical vulva occupying slightly more than half the space of sternite 6 (Fig. 6 F) (vs relatively larger, ovate and occupying most of the space of sternite 6, with the anterior edge touching sternal suture 5 / 6 in K. jolliveti n. comb.; Fig. 11 G). The differences in the structure of the posterior epistomial margin (i. e., whether the mxp 3 completely closes the anterior part of the buccal cavity), shape of the male telson, the very different proportions of the flagellum and basal part of the G 2, and the structures of the vulvae, however, are significant, and may suggest K. jolliveti n. comb. is not a member of Kallograea n. gen. That being said, the flat carapace, wide male anterior thoracic sternum, wide male pleon, and elongate male chelipeds with the rounded finger tips are important shared characters with K. kulolasi n. gen., n. sp., and indicate that placing Austinograea jolliveti in Kallograea n. gen. is the best decision for the time being. It is interesting to find two distinct species in a narrow perimeter on the periphery of the circular caldera of the Kulo Lasi Vulcano, an area with a diameter of only 5 km. The biota in this area, however, is known to be very dense and varied. Kallograea kulolasi n. gen., n. sp. seems confined to the Kulo Lasi Volcano, whereas the geographic range of K. jolliveti now extends from west to east, up to the Manus Basin (Figs 1 - 3). COMPARISON BETWEEN KALLOGRAEA N. GEN. (Figs 4 - 9) AND AUSTINOGRAEA HESSLER & MARTIN, 1989 (Figs 10; 11) The genus Austinograea is known from four species from the western Pacific: the type species A. williamsi Hessler & Martin, 1989, A. alayseae Guinot, 1990 (note that genetic differences have been found between individuals of A. alayseae from the Tofua Arc and the Manus Basin, see Kim et al. 2014), A. hourdezi Guinot & Segonzac, 2018, and A. chubacarc Guinot, 2025. A fifth species, A. rodriguezensis Tsuchida & Hashimoto, 2002, occurs in the western Indian Ocean. Austinograea williamsi (see Hessler & Martin 1989: figs 1, 2, 4, 5 a, 6 a, 7 a, 8 b, 9 - 11, 13 a, 14 a-d; Tsuchida & Fujikura 2000: figs 3, 5, 6, 8; Segonzac 2006: figs 1 - 4; see also Desbruyères et al. 2006; Kojima & Watanabe 2015: figs 25.1, 25.2), found in abundance in beds of the snail Alviniconcha hessleri Okutani & Ohta, 1988 that is common at the vent openings, is endemic to the Mariana Trough in the north-western Pacific, in the Mariana Back-Arc Basin, just west of the Mariana Island Arc. It should be noted that the ocular region of adult A. alayseae is not significantly different from that of adult A. williamsi (Hessler & Martin 1989: fig. 4): the orbital region is only more recessed in A. williamsi, but, likewise, the eye is vestigial, fused to the orbital floor, and replaced by a small oval region in the posterior orbital wall lateral to the antenna, and with a trace of cornea that is more or less discernible and virtually unpigmented (sometimes a small spot) (cf. Hessler & Martin 1989: figs 4, 5 a for A. williamsi; Guinot 1990: fig. 1 A, B for A. alysaeae). A key to the species of Austinograea was provided by Guinot & Segonzac (2018: 96). One species described from the western Pacific, Austinograea yunohana Takeda, Hashimoto & Ohta, 2000, was subsequently transferred by McLay (2007) to his new genus Gandalfus (see below). Kallograea n. gen. is markedly different from Austinograea in that the dorsal surface of the carapace is almost flat (Figs 4 A, C, E; 5 A; 6 A, E) (vs surface gently but distinctly convex in frontal view in Austinograea; Figs 10 A, C; 11 A); the posterior margin of the epistome is relatively wider (Figs 4 E; 6 E) (vs transversely narrower in Austinograea; Fig. 10 C); the ischium of the mxp 3 is distinctly elongate (Fig. 5 B) (vs shorter in Austinograea, except in A. williamsi; Fig. 10 H); the merus of the mxp 3 is subtriangular in shape, with the anterior part much produced (Figs 4 E; 5 B; 6 E) (vs subquadrate in Austinograea, except in A. williamsi; Fig. 10 H); the male anterior thoracic sternum is short and very wide (Fig. 4 B, D, F) (vs transversely narrower in Austinograea; Fig. 10 B, H, I); the adult male chelipeds are distinctly more elongate and slender, especially the merus that is longer, distinctly extending well beyond the carapace margin, and slender, narrow on its whole length, and regularly toothed on the dorsal margin (Figs 4 A-C; 5 C, D) (vs distinctly shorter and stouter, of moderate length and width in Austinograea [the chelipeds are relatively longer in A. willliamsi but still distinctly shorter than in Kallograea n. gen.]; Fig. 10 A, B); the adult male ambulatory legs are proportionately more slender and elongate, especially the merus and propodus (Fig. 4 A-C) (vs relatively shorter and stouter in Austinograea; Fig. 10 A, B); the male sternopleonal cavity is gently concave, relatively wide distally and without a concavity for the G 1 tip (Fig. 4 F) (vs cavity relatively deeper, relatively narrowing distally Fig. 10 I, sometimes with a distinct depression for the G 1 tips, in Austinograea); and the almost straight G 1 is positioned more or less longitudinally with the distal parts of each not overlapping (Figs 4 F, G; 7 A-D) (vs distinctly sinuous or straight with the distal parts of each overlapping to some degree in Austinograea (Fig. 10 I) [condition not clear for A. rodriguezensis, cf. Tsuchida & Fujikura 2000: fig. 8]. The form of the median lobe on the posterior epistomial margin of K. kulolasi n. gen., n. sp., being obtusely triangular (Figs 4 E; 6 E), is different from that of Austinograea species (acutely triangular in form; Fig. 10 C); and is more similar in condition to that in Gandalfus (Figs 12 B-D; 14 B, C; 15 B; 16 B), although the overall margin of K. kulolasi n. gen., n. sp. is distinctly wider. On the other hand, the median lobe of the margin in K. jolliveti n. comb., being acutely triangular (Figs 8 B; 9 B), is more similar in form to that of Austinograea species, although the overall margin is still wider in K. jolliveti n. comb. In Austinograea alayseae Guinot, 1990, the extremities of the G 1 join at the tips at the end of the sternopleonal cavity in situ and are positioned in a small deep depression (cf. Guinot 1990: 884, 891, fig. 2 C; Guinot & Segonzac 2006 a: fig. 5). In A. hourdezi Guinot & Segonzac, 2018 (Guinot 1990: figs 4 C, 6 C) and A. williamsi (Fig. 10 I), the G 1 tips also cross distally and are positioned in a narrow channel at the anterior part of the sternopleonal cavity. In contrast, in Kallograea n. gen., the obliquely directed G 1 have the tips well separated and the anterior part of the sternopleonal cavity is proportionally wider, flatter and without a special distal depression to receive the G 1 tips (Figs 4 F; 8 H). Another significant distinction between Austinograea and Kallograea kulolasi n. gen., n. sp. is observed in the length of the flagellum of G 2. It is much shorter than the basal article in Austinograea species (Fig. 10 I) and is as long as the basis in Kallograea kulolasi n. gen., n. sp. (Figs 4 H; 7 E). In K. jolliveti n. comb., the G 2 is proportionately shorter and the flagellum much shorter than that in K. kulolasi n. gen., n. sp. (Fig. 8 K); Guinot & Segonzac 2018: figs 9 D, 11 C-E). No other Austinograea species, except A. williamsi, in which the male crusher has rounded finger tips (Fig. 10 B, D, G), has finger tips as blunt as those on the crusher of Kallograea n. gen. Their overall cheliped structures, however, differ significantly, with that of Kallograea n. gen. being elongate and slender (Figs 4 A-C; 5 C-F; 8 A, C-F) and that of Austinograea, short and stout (Fig. 8 A, B, D, G). The above-discussed differences justify the transfer of Austinograea jolliveti into Kallograea n. gen., albeit with some reservations (see previously: Comparison between Kallograea kulolasi n. gen., n. sp. and K. jolliveti n. comb.). COMPARISON BETWEEN KALLOGRAEA N. GEN. (Figs 4 - 9) AND GANDALFUS MCLAY, 2007 (Figs 12 - 16) The type species, Gandalfus puia, has been collected from hydrothermal sites of the Kermadec Arc in the south-west Pacific Ocean, the longest underwater volcanic ridge on the planet, particularly in three active volcanoes between 30 ° 12 ’ S- 35 ° 44 ’ S and 181 ° 33 ’ E- 178 ° 29 ’ E (at 270 - 239 m, at 1604 - 1647 m, and at 337 m). The ridge, which forms the base of the Kermadec Islands, is linear for about 1000 km and is a prolongation of the Tonga ridge. The Tonga-Kermadec Ridge is underlying the Tonga-Kermadec island arc and, on its western side, it is flanked by the back-arc-basin, the Lau Basin, which is at the boundary of the Australian and Pacific Plates (De Ronde et al. 2001; Wright 2001; Wright et al. 2002; Hauff et al. 2021). The carapace of adult Gandalfus species is distinctly higher, with the dorsal surface more convex (Figs 12 A, C, D; 13 A, D; 14 A, B; 15 A; 16 A) compared to those of Kallograea spp. which are lower and flatter (Figs 4 A, C, E; 5 A; 6 A, E; 8 A, B; 9 A). The chelipeds of G. puia and G. yunohana are relatively short, have a short merus that is irregularly serrated and triangular in cross section, and a granulous and glabrous palm ending in relatively acute fingers that are armed with several proximal teeth of variable size, including one larger tooth at midlength of fixed finger (Figs 12 A, F, G; 13 A; 14 A, E-G; 15 E-H; 16 A, D, E) (vs adult male chelipeds distinctly more elongate, with the merus distinctly longer, slender along its entire length, with the dorsal margin dentate, and extending well beyond carapace margin; the stout palm possessing setal patches and ending in thick and blunt fingers, and on the major chela, there is only a molariform tooth on the fixed finger in Kallograea n. gen.; Figs 4 A-C; 5 C-F; 8 A, C-F). While adult Gandalfus spp. are generally larger (carapace width: 36.7 mm in G. puia; 42.2 mm in G. yunohana), we have subadult specimens of G. puia (e. g., female 10.4 × 14.3 mm, ZRC 2024.0726, ex MNHN-IU- 2024 - 6553) which are comparable in size to the two Kallograea species, but these differences remain valid. McLay (2007: fig. 2 D-F, table 2) recognised a new genus for his new species, Gandalfus puia, arguing that its G 2 was quite different from those of Austinograea s. str. In G. puia, the G 2 is approximately as long as the G 1, with the flagellum as long as or longer than the basal article. Because of this character, McLay (2007) transferred Austinograea yunohana Takeda, Hashimoto & Ohta, 2000 to Gandalfus (see Takeda et al. 2000: 164, 168, figs 4 I, 6 c, e) and, in doing so, he restricted Austinograea for species in which the G 2 is clearly shorter than the G 1, and has a shorter flagellum as well. The G 2 is distinctly less than half the length of the G 1 in A. williamsi (Fig. 10 I; Hessler & Martin 1989: fig. 14 a; Tsuchida & Fujikura 2000: fig. 6; Guinot & Segonzac 2006 c: fig. 4) and A. rodriguezensis (cf. Tsuchida & Hashimoto 2002: fig. 8; Tsuchida 2006: fig. 3); about half the length of the G 1 in A. hourdezi Guinot & Segonzac, 2018 (cf. Guinot & Segonzac 2018: fig. 6 D, E); and more than half the length of the G 1 (which is curved and armed with spiniform setae along its whole length) in A. alayseae Guinot, 1990 (cf. Guinot 1990: fig. 3 A-C; Guinot & Segonzac 2006 a: fig. 6). The discovery of the relative lengths of G 2 / G 1 in Kallograea kulolasi n. gen., n. sp. and K. jolliveti n. comb. reinforces the value of this character as a key taxonomic index. In both species of Kallograea n. gen., the G 2 is curved, and is as long as or shorter than the G 1 (Figs 4 H; 7 E; 8 K); with the flagellum slightly longer than the basal part. This is also one of the main characters that distinguishes Gandalfus from Austinograea. Another distinctive character of Gandalfus documented by McLay (2007), the slightly sinuous posterior epistomial margin (vs the strongly sinuous margin in Austinograea; see Tsuchida & Hashimoto 2002: fig. 3), was difficult to appreciate because, unfortunately, the shape of the epistome of G. puia was not clearly illustrated in McLay’s paper. Our examination of the two genera shows that the median lobe of the margin is obtusely triangular in Gandalfus (Figs 12 B-D; 14 B, D; 15 B; 16 B, C) but more distinctly acutely triangular in Austinograea (Fig. 8 C; Tsuchida & Hashimoto 2002: fig. 3). The posterior epistomial margin in both Kallograea species is distinctly wider than those of Gandalfus or Austinograea. As discussed earlier under Austinograea, the median lobe of this margin is obtusely triangular in K. kulolasi n. gen., n. sp. (Figs 4 E; 5 C; 6 E). McLay (2007: 7) described the vulva in a female of Gandalfus puia (carapace width 36.5 mm) as “ slit-like ”, oriented along anterior posterior body axis, not operculate, but he did not give an illustration. Gandalfus puia has a rounded vulva, with a distinct pointed tubercle at the anterior edge, which may be interpreted as a narrow sternal cover (Fig. 13 F), as that of G. yunohana illustrated by Takeda et al. (2000: 166, fig. 4 E, as Austinograea yunohana; Fig. 16 G). The vulva of K. kulolasi n. gen., n. sp. (Fig. 6 F) and K. jolliveti n. comb. (Fig. 9 G; Guinot & Segonzac 2018: fig. 10 E, as Austinograea jolliveti) is large, occupying most of the surface of sternite 6, and rounded, without any trace of an anterior tubercle. The vulva of Austinograea species is rounded, closed by soft membrane: in A. williamsi (Fig. 9 B) and A. hourdezi (Guinot & Segonzac 2018: fig. 10 E), without any trace of an anterior tubercle. The larvae of Gandalfus yunohana were reported on by Nakajima et al. (2010) and Hamasaki et al. (2010). The complete mitogenome of G. yunohana, from the Nikko Seamount on the Izu-Ogasawara Ridge, was reported by Yang et al. (2010: fig. 3) who showed that it had highly conserved characteristics and appeared to be related to brachyurans such as Pseudocarcinus gigas (Lamarck, 1818). Pseudocarcinus gigas is at present in its own family (see Ng & Davie 2020), and this supposed relationship needs to be revisited. The complete mitochondrial genome of G. puia, from the Tonga Arc, was obtained by Kim et al. (2015: fig. 1), showing that the genetic data of this taxon is distinct from that of Austinograea s. str. The phylogenetic tree of Wang et al. (2019: fig. 1) includes Gandalfus puia, G. yunohana, Austinograea alayseae, A. rodriguezensis and Segonzacia mesatlantica (Williams, 1988), and they show the same separation, indicating Gandalfus and Austinograea are separate genera (see also the Bayesian inference tree in Ma et al. 2024). Barcoding sequences of the mitochondrial COI gene of G. yunohana, from four vent fields (including two on the Izu Arc, one on the northern Mariana Arc and one in the Okinawa Trough), have shown a similar genetic diversity of populations on the Izu and northern Mariana Arcs and a sharing of the dominant haplotypes, without genetic subdivision regardless of the habitat depth, the whole suggesting a high dispersal capability for G. yunohana (cf. Watanabe et al. 2020).	en	Guinot, Danièle, Ng, Peter K. L. (2025): Kallograea kulolasi n. gen., n. sp. and K. jolliveti (Guinot & Segonzac, 2018) from the hydrothermal Kulo Lasi Volcano Caldera, West Pacific; and a reappraisal of Austinograea Hessler & Martin, 1989 and Gandalfus McLay, 2007 (Decapoda, Brachyura, Bythograeoidea). Zoosystema 47 (33): 773-797, DOI: 10.5252/zoosystema2025v47a33, URL: https://sciencepress.mnhn.fr/sites/default/files/articles/pdf/zoosystema2025v47a33_.pdf
