Catapagurus poupini, Lemaitre, 2025

Catapagurus poupini n. sp.

( Figs 1-3)

urn:lsid:zoobank.org:act:

TYPE MATERIAL. — Holotype. Marquesas Archipelago • ♂ 3.0 mm; Hiva Oa island; MUSORSTOM 9; stn CP1212; 09°49.9’S,

139°02.2’W; 50-80 m depth; shell sands with segment of Halimeda ; 29.VIII.1997; MNHN-IU-2022-4536.

Paratypes. Marquesas Archipelago • 2 ♂ 3.0- 3.1 mm; Hiva Oa Island ; N.O. Alis, MUSORSTOM 9; stn CP1215; 49-62 m depth; 09°49.5’S, 140°02.2’W; 29.VIII.1997; Bouchet, Dayrat, Richer de Forges legs; MNHN-IU-2022-4537 GoogleMaps • 1♂ 2.6 mm, 2 ovig. ♀ 2.5 mm, 2.6 mm; same data as for preceding; USNM 1441354 About USNM GoogleMaps • 5♂ 2.1-2.7 mm; Hiva Oa Island ; N.O. Alis, MUSORSTOM 9; stn CP1237; 95-305 m depth; 09°42’S, 139°04’W; 31.VIII.1997; Bouchet, Dayrat, Richer de Forges legs; MNHN-IU-2022-4538 GoogleMaps • 5 ♂ 2.1-2.8 mm; same data as for preceding; USNM 1441353 About USNM GoogleMaps .

OTHER MATERIAL EXAMINED. — Marquesas Archipelago • 7 ♂ 1.9-3.0 mm, 1 ♀ 3.0 mm, 5 ovig ♀ 2.4-2.8 mm, [most dismembered]; Hiva Oa Island ; N.O. Alis ; MUSORSTOM 9; stn CP1212; 09°49.9’S, 139°02.2’W; 50-80 m depth; 29.VIII.1997; Bouchet, Dayrat, Richer de Forges legs; USNM 1445847 About USNM GoogleMaps .

ETYMOLOGY. — The specific epithet, poupini , is given to acknowledge the important contributions to our knowledge of tropical Pacific and Indian Ocean decapods by Dr Joseph Poupin (École navale, Brest, France).

DISTRIBUTION. — At present known only from the Marquesas Archipelago; 50- 305 m.

HABITAT. — Housing unrecorded, probably empty gastropod shells; on shell sands with segments of Halimeda algae.

DESCRIPTION OF HOLOTYPE

Shield ( Fig. 1A)

Broader than long; anterior margin between rostral lobe and lateral projections concave; anterolateral margins sloping; posterior margin roundly truncate; dorsal surface slightly convex, smooth, with few sparse tufts of moderate short setae. Rostral lobe broadly rounded, not reaching level of lateral projections. Lateral projections broadly triangular, terminating in sharp spine. Carapace lateral lobes narrow, reaching slightly beyond midlength of shield. Posterior carapace with poorly calcified median plate; cardiac sulci distinctly calcified, reaching posterior margin. Branchiostegites unarmed.

Ocular peduncles ( Fig. 1A)

Short, stout, 0.6-0.7 length of shield, broadened distally, corneal diameter 0.5-0.6 of peduncular length; ocular acicles, slender, terminally acute, reaching mid-length of ocular peduncles, mesial margins each with fringe of long setae, separated basally by twice basal width of one acicle.

Antennular peduncles ( Fig. 1A)

Overreaching distal corneal margins by 0.2-0.5 length of penultimate segments; dorsolateral surfaces and dorsolateral distal angles of ultimate segments each with few long setae; penultimate segment glabrous; basal segment with spine at ventromesial distal angle.

Antennal peduncles ( Fig. 1A)

Overreaching distal corneal margins by nearly entire length of ultimate (fifth) segments; fifth and fourth segments each with few scattered setae; third segment with ventrodistal angle produced, with blunt terminal spine; second segment with dorsolateral distal angle produced, terminating in strong spine, dorsomesial distal angle with small spine; first segment with small spine on lateral face and at ventrodistal margin. Antennal acicles strong, reaching approximately mid-length of corneas, with few distal setae; mesial and lateral faces unarmed. Antennal flagella reaching to distal end of right chela; flagella naked.

Mouthparts

Not dissected. Third maxilliped with basis bearing four spine-like teeth; ischium crista dentata with six teeth (two spine-like proximally, four reduced and rounded distally), and prominent accessory tooth; merus with small dorsodistal spine.

Chelipeds ( Fig. 2)

Distinctly dissimilar, sparsely setose; left considerably slenderer than right; fingers bearing moderately long setae and denser than on rest of chelipeds, slightly crossed at tips, each terminating in small, blunt corneous claw.

Right cheliped ( Fig. 2A, B) moderately stout, exceeding left cheliped in distal extension by more than length of dactyl of right. Dactyl approximately 0.6 times as long as palm, with moderately long setae; dorsal surface convex, with scattered minute granules; dorsomesial margin not delimited, rounded and minutely granular; ventral and dorsal surfaces similar; cutting edge sinuous, armed with minute blunt teeth, distally forming a broadly rounded tooth, and sharp proximal tooth. Palm approximately as long as carpus; fixed finger with minutely granular surfaces (denser on lateral margin), cutting edge armed with minute blunt teeth, forming low, rounded tooth proximally; dorsal and ventral surfaces convex, dorsal surface with minute blunt to sharp granulation (stronger on dorsolateral and dorsomesial surfaces), dorsomesial and dorsolateral margins not delimited; ventral surface weakly granular. Carpus approximately equal to length of merus; dorsal, lateral and mesial surfaces distinctly granular, dorsolateral margin faintly delimited by small blunt spines proximally and small sharp spines distally, dorsomesial margin delimited by row of small spines increasing slightly in size distally; ventral surface weakly granular. Merus triangular in cross-section; dorsal, lateral and mesial surfaces with granules or small spines stronger than on carpus, with distinct dorsodistal spine; ventrolateral and ventromesial margins well delimited by granules or small spines; ventral surface weakly granular. Ischium row of small spines on ventrolateral margin. Coxa unarmed.

B A D C

B C A E F G D A, D G

Left cheliped ( Fig. 2C, D). Distinctly shorter than right, reaching when fully extended approximately midlength of right palm, sparsely setose; fingers crossing at tips when closed, each terminating in sharp, inwardly curved corneous claw. Dactyl approximately 1.2 times as long as palm; dorsal, mesial, and ventral surfaces granular and with few scattered moderately long setae; cutting edge with row of small corneous teeth. Palm approximately 0.6 timesas long as carpus; dorsal surface weakly convex; surfaces all bluntly to sharply granular, with scattered setae most abundant on fixed finger; fixed finger lateral margin with few blunt or sharp small tubercles, cutting edge with small corneous teeth. Carpus slightly longer than merus, surfaces all minutely granular; dorsomesial margin weakly defined, rounded; dorsolateral margin delimited by row of small acute spines increasing somewhat in size distally. Merus triangular in cross-section, with row of few stiff bristles on dorsal margin; surfaces minutely granular; dorsodistal unarmed. Ischium with blunt dorsal spine, ventrolateral margin with row of few small spines. Coxa unarmed.

Ambulatory legs ( Fig. 3)

Pereopods 2 and 3 similar except pereopod 2 somewhat shorter. Dactyls weakly blade-shaped; in dorsal view slightly twisted inwardly, in lateral view somewhat arched ventrally; approximately 1.1 times as long as of propodi, each terminating in sharp corneous claw; dorsal margins with one row of short bristle-like setae, ventral margins unarmed; lateral faces with weak median longitudinal groove, lateral face of pereopod 2 ( Fig. 3 A-C) unarmed, lateral face of pereopod 3 ( Fig. 3 D-F) with one row of six short stout corneous spinules on ventral half; mesial faces weakly concave. Propodi with all surfaces, dorsal and ventral margins, minutely granular or with scattered setae. Carpi with all surfaces minutely granular, dorsodistal margins each with one row of few minute blunt spines. Meri with surfaces minutely granulated; dorsal margins each with moderately long setae proximally, armed distally with a row of distinct spines (rows of two spines on each meri on left side, and a row of 3-5 spines on meri of right side).

Pereopod 4 ( Fig. 3G)

With preungual process at base of claw; dactyl terminating in short, curved corneous claw; propodal rasp consisting of one row of ovate scales. Sternite of third pereopods ( Fig. 1B) with short anterior lobe having distal margin subdivided by shallow u-shaped sinus into two setose lobes.

Male pereopod 5, sexual tube, and pleopods ( Fig. 1B,C)

With coxae ( Fig. 1B) roughly symmetrical; right coxa with sexual tube, left with gonopore obscured by fringe of setae; sexual tube ( Fig. 1B, C) long, slender, semitransparent, directed outward and curving over dorsal portion of pleon, terminally bilobed (one low lobe, and one slender, elongated lobe), spermatophores visible inside sexual tube; coxa of left with gonopore surrounded by dense fringe of setae. Male with three weakly developed left pleopods 3-5, pleopods 3 and 4 with rudimentary internal rami, pleopod 5 uniramous.

Females With pleopods 2-5 (pleopods 2-4 ovigerous).

Uropods ( Fig. 1D)

Asymmetrical; right protopod slightly produced posteriorly; exopods with moderately developed rasps.

Telson ( Fig. 1D)

Slightly asymmetrical, longer than broad, with distinct deep lateral indentations. Posterior lobes subtriangular, separated into two lobes by distinct, deep, U-shaped median cleft, outer margins broadly rounded with few short setae, apex of lobes with minute short bristles, inner margins unarmed.

Color

Unknown.

REMARKS

Among the 14 species of Catapagurus that have blade-shaped dactyls on pereopods 2 and 3, this new species is most similar to three of those species in having weakly blade-shaped dactyls. Those three species are: C. fimbriatus Komai & Rahayu, 2021 , C. insolitus Komai & Osawa, 2009 , and C. tenuilamina Komai, Miller & Malay, 2022 . However, that is where the similarity ends as there are a number albeit subtle characters that set C. poupini n. sp. apart from those other three.

This new species differs from Catapagurus fimbriatus as follows: shape of shield (barely broader than long in the new species vs distinctly broader than long in C. fimbriatus ); shape of cornea (roughly as broad as long in the new species vs distinctly broader than long in C. fimbriatus ); teeth on cutting edge of dactyl of right chela (armed with minute blunt teeth proximally and a distal rounded tooth in the new species vs having two unequal prominent blunt teeth in C. fimbriatus ); development of rasp on propodus of pereopod 4 (consisting of a long row of small scales in the new species vs a short row of relatively large scales in C. fimbriatus ); presence/absence of male gonopore on left coxa (present in the new species vs absent in C. fimbriatus ); and, telson lateral indentations and shape of posterior lobes (with distinct lateral indentations, and U-shaped median cleft separating terminally blunt posterior lobes in the new species vs wide trapezoidal median cleft separating terminally acute posterior lobes in C. fimbriatus ).

This new species differs from Catapagurus insolitus as follows: the shape and armature of antennal acicles (slender and unarmed mesially in the new species vs stout and armed with distinct spines mesially in C. insolitus ); length of pereopod 4 preungual process (short and barely exceeding dactyl claw in the new species vs long and distinctly exceeding dactyl claw in C. insolitus ); and, telson posterior lobes (separated by deep U-shaped median cleft in the new species vs separated by a a subrectangular median cleft in C. insolitus ).

This new species differs from Catapagurus tenuilamina as follows: length of pereopod 4 preungual process (short and barely exceeding dactyl claw in the new species vs long and distinctly exceeding dactyl claw in C. tenuilamina ); teeth on cutting edge of dactyl of right chela (armed with minute blunt teeth proximally and a distal rounded tooth in the new species vs one large blunt subtriangular tooth proximally and low round teeth distally in C. tenuilamana ); armature of ventromesial margin of dactyl of pereopods 2 and 3 (with one row of about six minute corneous spinules in the new species vs with one row of about 20 minute spinules in C. tenuilamina ); presence/absence of male gonopore on left coxa (present in the new species vs absent in C. tenuilamina ); and terminal shape of sexual tube (bilobed with one low lobe slender, elongated vs bilobed with both lobes short and rounded in C. tenuilamina ).