Leptopagurus rhabdotus, Lemaitre & Felder & Poupin, 2017

Lemaitre, Rafael, Felder, Darryl L. & Poupin, Joseph, 2017, Discovery of a new micro-pagurid fauna (Crustacea: Decapoda: Paguridae) in the Lesser Antilles, Caribbean Sea, Zoosystema 39 (2), pp. 151-195 : 154-160

publication ID	https://doi.org/ 10.5252/z2017n2a1
publication LSID	urn:lsid:zoobank.org:pub:5C83606A-10C1-449A-B5AC-AF88BE563671
persistent identifier	https://treatment.plazi.org/id/03F387EB-FFB0-4551-FFAC-F9FF660BFA5B
treatment provided by	Marcus
scientific name	Leptopagurus rhabdotus
status	sp. nov.

Treatment

Leptopagurus rhabdotus View in CoL n. sp.

( Figs 1-4 View FIG View FIG View FIG View FIG ; Table 1)

TYPE MATERIAL. — Holotype. ♂ 1.1 mm, Curaçao, ARMS 14, 224 m, 15.IX.2015, BCURA 0668 , USNM 1297635 About USNM ( ULLZ 16890 View Materials ) . Paratypes. Curaçao: 1 ♂ 1.5 mm, ARMS 22, 224 m, 15.IX.2015, BCU- RA 1499, USNM 1297449 About USNM ( ULLZ 16921 View Materials ) ; 1 ♂ 1.0 mm, CURASUB 15-26, Playa Forti , Westpoint, 12°22’4.8”N, 69°09’18”W, 124.6- 198.4 m, 29.IX.2015, CURI 15048 , USNM 1297279 About USNM GoogleMaps .

Dominica: 1♂ 0.9 mm, Prince Rupert Bay, Portsmouth, near Picard Beach Cottage, CURASUB 16-12, 15 33’25.2576, 61 28’15.3804, 50-178 m, 8.III.2016, inside glass bottle, DOMnt 16016, USNM 1291967.

ETYMOLOGY. — The specific name is from the Greek rhabdotos, meaning striped, in reference to the striped color pattern of the chelipeds and ambulatory legs of this new species.

DISTRIBUTION. — So far known only from off Willemstad, Curaçao, and off Portsmouth, Dominica, in the Caribbean Sea. Depth: 50- 224 m.

HABITAT. — Found in gastropod shells on ARMS and inside glass bottles.

DESCRIPTION

Shield ( Fig. 1A View FIG )

Subovate, glabrous, at most with scattered setae anteriorly, about 1.2 times as long as broad; anterior margin between rostrum and lateral projections weakly concave; anterolateral margins sloping; posterior margin roundly truncate. Rostrum bluntly subtriangular, reaching slightly beyond level of lateral projections. Lateral projections subtriangular, each terminating in sharp spine.

Ocular peduncles

About 0.7 length of shield, glabrous except for dorsomesial distal bristle; corneas large but weakly dilated. Ocular acicles subtriangular, dorsal surface flat; terminating in bifid spine.

Antennular peduncles

Exceeding distal margins of cornea when fully extended by about 0.7 length of ultimate segment. Ultimate segment naked except for scattered shirt setae dorsally. Penultimate and basal segments naked; basal segment with blunt ventromesial angle, and small spine on lateral face.

Antennal peduncles

Exceeding distal margins of corneas when fully extended by about 0.8 length of fifth segment. Fifth and fourth segments unarmed except for scattered short setae or bristles. Third segment with small spine on ventrodistal angle. Second segment with dorsolateral distal angle produced into spine-like process slightly overreaching distal margin of third segment; dorsomesial distal angle with small spine. First segment unarmed. Antennal acicle not exceeding distal margin of cornea, broadly curving outward and terminating in strong spine, mesial margin with few setae or bristles. Flagella long, exceeding tips of chelipeds, with few short setae <1 flagellar article in length.

Mouthparts ( Fig. 1B, C View FIG )

Mandible with incisor process calcareous. Maxillule with internal and external lobes weakly produced, subequal, internal lobe with long terminal seta. Maxilla with endopod slender, slightly shorter than distal lobe of basal endite but overreaching distal margin of scaphognathite. First maxilliped with endopod distally spatulate. Second maxilliped ( Fig. 1B View FIG ) with relatively stout propodus-dactyl, propodus height larger than length, dactyl nearly as long as propodus and equilaterally triangular. Third maxilliped ( Fig. 1C View FIG ) ischium with crista dentata consisting of row of short, sharp teeth, and one accessory tooth.

Right cheliped ( Fig. 2 View FIG A-C)

Chelipeds slender, subequal in length. Right cheliped glabrous except for scattered setae or bristles. Chela with dorsal and ventral surfaces smooth, lacking armature except for few minute low tubercles proximally on dorsal surface of fixed finger. Fingers each terminating in sharp corneous claw slightly overlapping when closed. Dactyl 0.7 length of palm, cutting edge with two large, unequal calcareous teeth, row of fused small teeth forming uneven edge distally; ventromesial face smooth. Fixed finger similar to dactyl except for cutting edge having two broader, lower calcareous teeth, dorsolateral margin weakly defined by microscopic tubercles continued to mid-portion of palm; ventromesial surface smooth. Palm 1.4 times as long as broad, about 0.7 as long as carpus, dorsal surface convex, unarmed except for scattered short setae, dorsolateral margin rounded proximally; dorsomesial margin rounded; ventral surface convex, glabrous. Carpus about 2.5 as long as broad, subequal to merus in length; dorsal surface weakly convex, with few moderately long setae or bristles; dorsomesial margin unarmed or with few small spines, dorsolateral margin lacking spines; lateral face rounded, mesial face flat, nearly vertical; ventral surface smooth or with few weak low tubercles. Merus subtriangular in cross- section; ventral face with distinct capsulate setae clustered proximally, arranged in row on lateral and mesial margins ( Fig. 2B, C View FIG ), distolateral margin with row of sharp spines, distomesial margin with row of small mostly blunt spines. Ischium glabrous. Coxa with row of setae on ventromesial distal angle.

Left cheliped ( Fig. 2 View FIG D-F)

Narrowly elongate, chela glabrous except for sparse short setae; dactyl and fixed finger each terminating in sharp corneous claw slightly overlapping when closed, cutting edges consisting of row of mostly fused minute corneous teeth. Dactyl about as long as palm; dorsal and ventral surfaces rounded. Palm dorsal surface with weakly raised longitudinal median ridge armed with minute tubercles; ventral surface convex, smooth. Carpus about as long as merus; dorsal surface nearly flat, dorsodistal margin unarmed; dorsomesial margin with several long capsulate setae proximally and sparse setae distally; dorsolateral margin with row of tufts of short setae; ventral surface convex. Merus subtriangular in cross-section; dorsal margin with row of short tufts of setae; ventral surface with cluster of several long capsulate setae ( Fig. 2E, F View FIG ); ventrolateral and ventromesial margins each with row of small spines. Ischium glabrous. Coxa with row of setae on ventromesial distal angle.

Ambulatory legs ( Fig. 3 View FIG A-D)

Long, slender, exceeding tip of chelipeds by about 0.3 length of dactyls when fully extended, sparsely setose. Dactyls each broadly curved, about 1.1 times as long as propodus, terminating in sharp corneous claw; with ventromesial row of eight or nine slender corneous spinules each arranged in small acute angle; with dorsal row of moderately long setae. Propodi each broadly curved, few setae on dorsal and ventral margins, lateral and mesial faces glabrous. Carpi each with blunt dorsodistal angle, few setae on dorsal margin. Meri each somewhat laterally compressed, lateral and mesial faces glabrous, dorsal margin with few long setae; ventral margin with row of several long, well spaced capsulate setae (pereopod 2) or simple setae (pereopod 3). Ischia with capsulate setae on ventrodistal angle (pereopod 2) or simple setae (pereopod 3). Anterior lobe of sternite XI (of pereopods 3; Fig. 1D View FIG ) subsemicircular, fringe of short setae on distal margin.

Fourth pereopods ( Fig. 1E View FIG )

Semichelate. Dactyl weakly curved, terminating in short, inwardly directed corneous claw, lacking preungual process; propodal rasp with single row of ovate corneous scales. Carpus unarmed except for few short setae dorsally. Merus unarmed except for with dorsodistal tuft of long setae.

Fifth pereopods

Chelate. Propodal rasp extending on dorsal surface for about 0.7 length of propodus.

Uropods and telson ( Fig. 1F View FIG )

Uropods markedly asymmetrical, left largest. Telson nearly symmetrical, longer than broad, with distinct lateral indentations; anterior lobes about as long as posterior lobes; posterior lobes with chitinous lateral margins, lobes separated by U-shaped median cleft, terminal margins weakly oblique, each armed with four spines, lateral-most strongest, curving ventrolaterally.

Sexual tubes ( Fig. 1G View FIG ) and pleopods

Males with coxae of pereopods 5 symmetrical, with short, subequal, stout, membranous sexual tubes ( Fig. 1G View FIG ) curving forward; posterior portion of gonopores each with fringe of setae; with unpaired left pleopods 3-5. Females unknown.

Genetic data

See Table 1.

Colour ( Fig. 4 View FIG )

Shield and ocular acicles white. Ocular peduncles orange with broad median white or semi-transparent stripe; corneas dark with white iridescence. Antennular and antennal peduncles light orange on lateral and mesial faces, otherwise semitransparent white. Chelipeds with dorsal surfaces of chelae light orange except for whitish tone on teeth and cutting edges of dactyl and fixed fingers; meri and carpi each with three light orange stripes on dorsal surfaces. Ambulatory legs semitransparent white; meri, carpi and propodi each with two light orange stripes on lateral and mesial surfaces, and orange dorsal margins.

REMARKS

In addition to generic characters, this minute new species stands out among western Atlantic pagurids by the striking, striped color pattern ( Fig. 4 View FIG ). The capsulate setae on the ventral faces of the meri of both chelipeds also provide a distinguishing character, and conceivably these may serve some presently unknown specialized function. Somewhat similar capsulate setae to those found in Leptopagurus rhabdotus n. gen., n. sp., have been reported in a number of species of pagurid genera, although not on the ventral faces of the cheliped meri, instead being found on the third through fifth sternites in some species of Pylopagurus A. Milne Edwards & Bouvier, 1893 , on the lateral and mesial faces of the left cheliped carpus in Cycetopagurus morgani McLaughlin, 2004 , and on dorsal and mesial surfaces of the carpi of right and left chelipeds Pseudopagurodes annae Rahayu & Komai, 2013 , and P. capsellatus Rahayu & Komai, 2013 .

Of the micro-pagurids included in this report, Leptopagurus rhabdotus n. gen., n. sp. is the only species that has been found in more than one island locality, being collected in both Curaçao and Dominica.

Genus Nematopaguroides

Forest & de Saint Laurent, 1968

Nematopaguroides Forest & de Saint Laurent, 1968: 156 View in CoL . — Wang & McLaughlin 2000: 957. — McLaughlin 2003: 125 View Cited Treatment .

TYPE SPECIES. — Nematopaguroides fagei Forest & de Saint Laurent, 1968 , by original designation.

REMARKS

Prior to the present description, Nematopaguroides included only two species, both distributed in western Atlantic, N. fagei Forest & de Saint Laurent, 1968 and N. pusillus Forest & de Saint Laurent, 1968 .