Hexaplax saudade, Rahayu & Ng, 2014

Rahayu, Dwi Listyo & Ng, Peter K. L., 2014, New genera and new species of Hexapodidae (Crustacea, Brachyura) from the Indo-West Pacific and east Atlantic, Raffles Bulletin of Zoology 62, pp. 396-483 : 474-478

publication ID

https://doi.org/ 10.5281/zenodo.5353945

publication LSID

lsid:zoobank.org:pub:4CF42744-861A-4635-9703-E6639CEBFAA9

persistent identifier

https://treatment.plazi.org/id/64CF39E2-D2DA-49A7-9DBA-544FE12EB756

taxon LSID

lsid:zoobank.org:act:64CF39E2-D2DA-49A7-9DBA-544FE12EB756

treatment provided by

Tatiana

scientific name

Hexaplax saudade
status

sp. nov.

Hexaplax saudade View in CoL , new species

( Figs. 2G, H View Fig , 56D View Fig , 57D View Fig , 58D View Fig , 59G, H View Fig , 60C View Fig , 61B View Fig , 65 View Fig , 66 View Fig )

Hexaplax megalops View in CoL – Serène, 1964: 270, text fig. 21, pl. 24A; Sakai, 1965: 40, 45, pl. 6 fig. 8; Sakai, 1976: 556, pl. 196 fig. 4; Ng et al., 2008: 86 (part), fig. 78. (not Hexaplax megalops Doflein, 1904 View in CoL )

Material examined. Holotype: male (16.4 × 12.1 mm) ( NMCR), station CP 2660, 15°52.2'N 121°48.8'E, 542 m, Philippines, coll. AURORA 2007 Expedition , 20 May 2007 GoogleMaps . Paratypes: Philippines: 3 males (11.6 × 8.2 mm, 14.8 × 10.5 mm, 18.2 × 13.2 mm) , 3 females (14.3 × 10.8 mm, 14.6 × 10.6 mm, 16.9 × 9.8 mm, 18.6 × 13.6 mm) ( ZRC 2013.1692 View Materials ) , 3 males (13.6 × 9.7 mm, 15.3 × 11.2 mm, 17.2 × 12.0 mm), 2 females (15.2 × 11.1 mm, 15.8 × 11.7 mm) ( MNHN), station CP 2658, 15°58.03'N 121°49.11'E, 422 m, coll. AURORA 2007 Expedition , 20 May 2007 GoogleMaps ; 1 male (16.4 × 12.1 mm), 1 female (11.4 × 8.0 mm) ( ZRC 2013.1693 View Materials ), station CP 2660, 15°52.2'N 121°48.8'E, 542 m, coll. AURORA 2007 Expedition , 20 May 2007 GoogleMaps ; 1 male (17.9 × 12.7 mm), 2 females (16.6 × 12.3 mm, 13.1 × 9.7 mm) ( ZRC 2013.1694 View Materials ), station CP 2735, 15°59.52'N 121°50.93'E, 431 m, coll. AURORA 2007 Expedition , 1 June 2007 GoogleMaps . Others: Taiwan: 1 male (15.9 × 11.1 mm) ( ZRC 2008.1456 View Materials ), Su- Ao fish port, Ilan province , trawled, deep-sea, coll. C.-W. Lin, 29 July 2004 . Japan: 1 male (15.1 × 11.6 mm) (NSMT-Cr 13586), Tosa Bay , 400 m, coll. Kotaka Maru, M. Takeda, 9 May 2000 .

Diagnosis. Carapace subquadrate ( Fig. 65A View Fig ), about 1.4 times as broad as long, dorsal surface very finely granulated; regions indistinct, median H-shaped depression shallow. Anterolateral margin arcuate; posterolateral corner with small angle over base of posterior pereopods. Front not deflexed (Fig. and 56D), divided into 2 lobes, not projecting beyond distal edge of orbits. Orbit distinct, transverse; eye movable, large, corneas dilated, pigmented, much wider than peduncle ( Fig. 56D View Fig ). Pterygostomial region with oblique stridulatory ridge consist of long row of 24 short, widely-spaced striae, including ca. 14 shorter, less produced striae adjacent to epistome ( Fig. 60C View Fig ); shallow oblique groove above ridge. Third maxillipeds broad ( Fig. 66A View Fig ), not covering buccal cavity, with gap when closed; ischium longer than broad, longer than merus, with scattered granules, dilated distally, mesial margin rounded; merus squarish, as long as broad; dactylus longer than propodus; exopod relatively narrow, less than 0.3 width of ischium; flagellum well developed. Chelipeds subequal ( Fig. 57D View Fig ); major chela with slight gap when fingers closed; with large teeth at cutting edge of dactylus and fixed finger; outer surface of dactylus with 2 longitudinal ridges; inner surface near upper margin with longitudinal ridge; palm longer than wide, outer surface finely granulated; fixed finger with 2 longitudinal ridges; lower margin with row small teeth continuing to lower margin of palm; carpus finely granulated on outer surface, inner angle blunt, upper margin with row of small tubercles obscured by short setae, long setae on outer angle; merus short, row of denticles on outer and inner lower margins, fringe of setae dorsomesially. Minor chela without gap when fingers closed; ornamentation similar to that of major chela. P2–P4 long, slender ( Fig. 65 View Fig ); outer surface finely granulated; merus of P4 about 7 times as long as broad ( Fig. 59G, H View Fig ). Male thoracic sternum broad ( Fig. 58D View Fig ), surface finely granular; sternites 1 and 2 fused, separated from sternite 3 by distinct ridge; sternite 3 not separated from sternite 4, sternites 4–7 well developed, separated by distinct sutures; sternoabdominal cavity reaching middle of sternite 4, no thoracic sternal groove; sternite 8 exposed, triangular, reaching half length of male abdominal somite 2. Male abdomen relatively narrow ( Figs. 58D View Fig , 66B View Fig ); somite 1 hidden under carapace; somite 2 free, somites 3–5 fused, lateral margin sinuous; somite 6 wider than long, lateral margin slightly expanded subproximally; telson rounded, as long as somite 6. Female abdomen not much wider than male ( Fig. 66E View Fig ), 6 free somites and telson, first somite hidden under carapace. G1 ( Fig. 66C, D View Fig ) concealed under abdomen, straight, distal part tapered, sparse short setae present in proximal half, small spinules on mesial margin medially.

Colour. In life, the carapace is light brown with a tinge of orange or orangish-brown medially. The cheliped transparent white with an orange line at the articulation of the dactylus and palm; P2–P4 transparent are whitish on the dactylus, propodus and carpus; with the merus light brown tinged of orange distally ( Fig. 2G, H View Fig ).

Etymology. The species name is derived from the Portuguese word “saudade” which means a melancholic longing for something that cannot exist or be realised; alluding to the long-held belief that Hexaplax was a monotypic genus. The name is used as a Latin noun in apposition.

Remarks. See remarks for H. megalops s. str. for differences with congeners.

The records of “ Hexaplax megalops ” from Philippines ( Serène, 1964; Ng et al., 2008) and Tosa Bay in Japan ( Sakai, 1965; Sakai, 1976) are clearly Hexaplax saudade , new species. The figure of a fresh specimen in Sakai (1965, 1976) agrees well with those of the new species from Philippines ( Fig. 2E View Fig ) and Taiwan ( Fig. 2F View Fig ). We have also examined a male specimen from Tosa Bay specimen (NSMT-Cr 13586) which agrees with our definition of H. saudade .

Type locality. Philippine Sea , Philippines .

Distribution. Philippines, Taiwan and Japan. Deep water, 422– 542 m.

NMCR

New Mexico State University

MNHN

Museum National d'Histoire Naturelle

Kingdom

Animalia

Phylum

Arthropoda

Class

Malacostraca

Order

Decapoda

Family

Hexapodidae

Genus

Hexaplax

Loc

Hexaplax saudade

Rahayu, Dwi Listyo & Ng, Peter K. L. 2014
2014
Loc

Hexaplax megalops

Ng PKL & Guinot D & Davie PJF 2008: 86
Sakai T 1976: 556
Sakai T 1965: 40
Serene R 1964: 270
1964
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