Trizocheles vaubanae, Mclaughlin, Patsy A. & Lemaitre, Rafael, 2008

Mclaughlin, Patsy A. & Lemaitre, Rafael, 2008, Larvae of two species of Trizocheles (Decapoda: Anomura: Paguroidea: Pylochelidae: Trizochelinae), description of the adult of one, and preliminary implications of development on pylochelid phylogeny, Zootaxa 1911, pp. 52-68 : 62-66

publication ID	https://doi.org/ 10.5281/zenodo.184552
DOI	https://doi.org/10.5281/zenodo.6234958
persistent identifier	https://treatment.plazi.org/id/03D48790-993B-FFF7-FF2F-FBA5FB5BFD29
treatment provided by	Plazi
scientific name	Trizocheles vaubanae
status	sp. nov.

Treatment

Trizocheles vaubanae n. sp.

( Figs 5 View FIGURE 5 , 6 View FIGURE 6 )

Type material. New Caledonia. Holotype: ovigerous female (sl = 7.8 mm) NORFOLK 2 stn CP 2050, 23º42’S, 168º16’E, 377 m, 24 Oct 2003 (MNHN-Pg 7766).

Paratypes: 1 ovig. female (2.4 mm), BIOCAL, stn DW 66, 24º55.43’S, 168º21.67’E, 505–515 m, 3 Sep 1985 (MNHN-Pg 7767); 1 male (sl = 2.2 mm), SMIB 3, stn CP 1, 22º53.0’S, 167º12.0’E, 437 m, 5 Feb 1986 (MNHN-Pg 7768); 2 males (sl = 2.7, 2.9 mm), CHALCAL 2, stn DW 72, 24º54.5’S, 168º22.3’E, 527 m, 28 Oct 1986 (MNHN-Pg 7769); 1 male (sl = 4.3 mm), BERYX 2, stn DW 38, 23º38’S, 167º39’E, 550–690 m, 19 Oct 1992 (MNHN-Pg 7770); 1 female (sl = 2.4 mm), NORFOLK 2, stn DW 2147, 22°50’S, 167°16’E, 496 m, 4 Nov 2003 (MNHN-Pg 7771); 1 male (sl = 2.7 mm), stn 2050, same data as holotype, (MNHN- Pg 7772); 2 males (sl = 2.6, 2.8 mm), 1 ovig. female (3.6 mm), stn DW 2057, 24º40’S, 168º39’E, 555–565 m, 25 Oct 2003 (MNHN-Pg 7773); 1 ovig. female (sl = 3.4 mm), stn CP 2061, 24º37’S, 168º40’E, 620–1040), 25 Oct 2003 (MNHN-Pg 7774); 1 male (sl = 2.3 mm), 1 female (sl = 2.4 mm), 3 ovig. females (sl = 2.4–3.3 mm), stn DW 2081, 25°54’S, 168°22’E, 500–505 m, 28 Oct 2003 (MNHN-Pg 7775); 1 male (sl = 5.1 mm) stn DW 2087, 24º56’S, 168º22’E, 518–586 m, 28 Oct 2003 ( USNM 1114242); 1 ovig. female (sl = 7.2 mm), EBISCO, stn DW 2584, 19º38.0’S, 158º44.0’E, depth not recorded, 15 Oct 2005, ( USNM 1114243); 1 ovig. female (sl = 4.2 mm, with prematurely hatched metazoeae), stn DW 2606, 19º36.0’S, 158º42.’E, 442–443 m, 18 Oct 2005, (MNHN-Pg 7776).

Solomon Islands. 1 female (sl = 4.8 mm), SALOMON 2, stn CP 2261, 8°01.9’S- 156°54.1’E, 433-470 m, Nov 2004 (MNHN-Pg 7778).

Other material examined. New Caledonia. 1 ovig. female (2.0 mm), SMIB 4, stn DW 55, 23º24.1’S, 168º04.5’E, 260 m, 9 Mar 1989 ( MNHN Pg 7777).

Description. Shield ( Fig. 5 View FIGURE 5 a) distinctly broader than long, and longer than calcified posterior carapace; dorsal surface with moderately long, deep, transverse groove subrostrally. Cervical groove clearly delineated laterally. Shield lateral margins each with slight indentation to small spine in proximal half. Posterior median plate well delineated, broad anteriorly and narrowing posteriorly, moderately well calcified; sulci cardiobranchialis not apparent. Branchiostegites weakly calcified anterodorsally; dorsal margin unarmed, usually few spinules on distal margin. Rostrum typically broadly triangular, with or without small marginal spinule, approximately reaching level of lateral projections, occasionally obsolete. Lateral projections well developed, each with marginal spine.

Ocular peduncles 0.5–0.8 length of shield; corneas 0.3–0.5 of peduncular length. Ocular acicles moderately small, acutely triangular, calcified only in anterior halves; widely separated.

Antennular peduncles overreaching distal corneal margins by 0.5–0.7 lengths of ultimate segments. Ultimate segment approximately equal in length to penultimate segment or slightly shorter. Basal segment with spine on statocyst lobe laterally and spinule at ventrodistal margin.

Antennal peduncles reaching midlength of corneas; with supernumerary segmentation. Fifth segment unarmed; fourth segment with spine at dorsodistal margin; third segment with spine at ventrodistal margin; second segment with dorsolateral distal angle produced, with terminal bifid spine, dorsomesial distal angle with small spine; first segment with 2 or 3 small spines ventrolateral margin.

Antennal acicle short, not reaching beyond midlength of ocular peduncle (exclusive of cornea), usually terminating in bifid spine, rarely simple, mesial margin with 1 or 2 spines, lateral margin unarmed or with 1 spine in distal half. Antennal flagella as short as carapace; most articles each with 2–4 short to moderately long setae.

Second segment of mandibular palp ( Fig. 5 View FIGURE 5 b) with roundly subrectangular dorsomesially projected lobe and dorsoproximal small spiniform protuberance. Maxillule ( Fig. 5 View FIGURE 5 c) with external lobe of endopod obsolete. Maxilla ( Fig. 5 View FIGURE 5 d) 2 very long setae on ventral margin of proximal lobe of scaphognathite. First maxilliped ( Fig. 5 View FIGURE 5 e) with well developed, marginally setose epipod. Second maxilliped ( Fig. 5 View FIGURE 5 f) with small tubular epipod. Third maxilliped ( Fig. 5 View FIGURE 5 g, h) with unarmed exopod; endopod with 3 or 4 small teeth on basis; ischium with well developed crista dentata, 1 accessory tooth, 1 dorsodistal and 1 ventrodistal spine; merus with 1 dorsodistal and 1 smaller subdistal spine; carpus with dorsodistal spine; termination simple.

Chelipeds subequal and symmetrical; with propodal-carpal rotation of approximately 45°; chelae and carpi ( Fig. 6 View FIGURE 6 a) each with moderate covering of long setae on upper and outer surfaces not concealing armature. Dactyl 0.6–0.7 length of palm, with moderately narrow hiatus between dactyl and fixed finger; upper margin with 1 or 2 large, corneous-tipped spines proximally and row of much smaller, often subacute, spines; outer face also with large corneous-tipped proximal spine and row of smaller spines extending to or nearly to tip; cutting edge with row of moderately large, calcareous teeth, terminating in prominent corneous claw; inner face with few scattered setae. Palms 1.5–1.7 length of carpus; upper margin with row of prominent large spines, outer surface of palms with 4 rows of smaller spines, lower outer surface with scattered small tubercles; fixed finger with distinct row of subacute marginal spines and adjacent row of small tubercles, cutting edge with row of moderately large calcareous teeth and terminal corneous claw. Carpus subtrapezoidal; upper margin with 2 large and 1 or 2 somewhat smaller spines, outer surface with 3 or 4 spines; outer lower face with several rows of stridulatory rods and tubercles; inner face with 1 or 2 small tubercles and tufts of short setae; ventral surface smooth. Merus subtriangular; dorsal margin with spine, often corneous-tipped, at distal margin and row of setae proximally, mesial and lateral faces unarmed, ventromesial and ventrolateral margins each with row of small tubercles or spines; ventral surface with 1 or 2 small tubercles proximally. Ischium with row of large spines on ventromesial margin.

Second and third pereopods ( Fig. 6 View FIGURE 6 b–d) equaling or slightly overreaching chelipeds. Dactyls 0.1–0.2 longer than propodi; dorsal and mesial faces each with tufts of stiff setae; ventral margins each usually with 5– 7 corneous spines and tufts of setae. Propodi 0.2–0.3 longer than carpi; dorsal margins of second pereopods each with tufts of long setae, irregular often incomplete double row of acute large spines, single or incomplete double, also irregular row on third, often fewer in number; mesial faces of second pereopods each with numerous stridulatory tubercles or short ridges, scattered or forming irregular rows, third unarmed or with row of quite small, widely-spaced tubercles; ventral surfaces of second pereopods each with few scattered setae, occasionally corneous spine at ventrodistal margin, third with or without corneous spinule at ventrodistal margin and row of widely spaced protuberances and tufts of setae, occasionally concealing additional corneous spinule(s); lateral faces unarmed. Carpi of both second and third pereopods each with dorsal row of prominent spines and tufts of moderately long setae in large individuals, third often with only 1–3 spines in small specimens, lateral faces each with shallow median longitudinal sulcus; mesial faces of second pereopods each with row of prominent stridulatory ridges. Meri of second pereopods each often with row of small spinules or tubercles on ventral margin, sometimes not discernable, third only with few tufts of setae. Fourth pereopods semichelate; each with propodal rasp consisting of several rows of corneous scales; propodi and carpi each with dorsodistal spine. Fifth pereopods chelate; propodal rasp well developed.

Pleon with tergite 1 moderately well calcified; tergites 2–5 weakly calcified, pleura weakly delineated; tergite of pleomere 6 ( Fig. 6 View FIGURE 6 e) roundly subquadrate, with deep lateral incisions and shallow median longitudinal sulcus; terminal margin straight, slightly sinuous, or with shallow to moderately deep, broad, median concavity, unarmed. All tergites and telson usually with covering of short setae.

Uropods symmetrical; protopods each with posteriorly directed spine. Telson with faint lateral indentations dividing telson into unequal anterior and posterior portions; posterior lobes considerably shorter, separated by deep median cleft, terminal margins rounded, unarmed but with fringe of fine setae.

Males with paired first pleopods ( Fig. 5 View FIGURE 5 i) 2-segmented, distal segments each terminally spatulate; paired second pleopods ( Fig. 5 View FIGURE 5 j) also 2-segmented, spatulate terminal segments quite broad; pleopods 3–5 each with exopod well developed, endopod reduced.

Females with slender, 2-segmented first pleopods each with numerous setae marginally and terminally.

Etymology. This species is named for the research vessel R.V. Vauban, from which the first specimens were collected.

Habitat. Carcinoecia usually missing; one specimen found occupying a gastropod shell and another lodged in the lumen of a piece of a dead stony coral.

Distribution. New Caledonia, Solomon Islands; 377–620 m, possibly as shallow as 260 m or as deep as 1040 m.

Variation. Variations in the number of ventral spines on the dactyls of the ambulatory legs and on the dorsal surfaces of the carpi of the third pereopods appear to be functions of size. Small specimens typically had five spines on the dactyls and one or two on the carpi; these often increased in number with increased animal size; however, in the large female holotype, the dorsal surface of the third left carpus had four spines, but only two on the right. The terminal margin of the sixth pleomere also appeared influenced by animal size. The margin typically was straight in small specimens but appeared more sinuous with increased size, because marginal calcification diminished, ultimately giving the impression of a broad median concavity in the largest individuals.

Remarks. Trizocheles vaubanae n. sp. is most closely allied to T. s. spinosus and T. s. bathamae Forest & de Saint Laurent, 1987 in having spines on the dorsal margins of the propodi and carpi of both the second and pereopods as well as prominently developed stridulatory rods and/or tubercles on the mesial faces of the second pair. However, like T. pulcher Forest, 1987 and T. pilgrimi Forest & McLaughlin, 2000 , the propodal spines of T. vaubanae n. sp. form one or two, usually incomplete, irregular rows rather than the single regular row seen in the two subspecies of T. spinosus . Trizocheles pulcher and T. pilgrimi are immediately distinguished from the new species by having the dorsal spines on the propodi of only the second pereopods; the propodi of the third pereopods are unarmed or each has only a small dorsodistal spine. The ovigerous female from SMIB 4, stn DW 55, differs from the other females in having only a distal pair of spines on the propodus of each second pereopod rather than the typical row(s). Whether this is because of its smaller size is uncertain, but it only can questionably be assigned to T. vaubanae n. sp. It is not considered a paratype.