Nematopaguroides karukera, 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 : 160-165

Nematopaguroides karukera n. sp.

( Figs 5-8 ; Table 1)

TYPE MATERIAL. — Holotype. ♂ 1.3 mm, Guadeloupe, sta GS 15, off Deshaies , Sec Ferry, 16°17.51’N, 61°48.96’W, 27 m, 12.V.2012, MNHN-IU-2013-5307.

Paratypes. Guadeloupe: 1 ♂ 1.2 mm, sta GB 03, 16°21.72’N, 61°36.35’W, 22 m, 5. V.2012, MNHN-IU-2013-5634 ( USNM 1292074 ) ; 1 ovig ♀ 0.9 mm, sta GD 05, 16°22.61’N, 61°36.33’W, 80 m, 5. V.2012, MNHN-IU-2013-5636; 1 ♂ 1.4 mm, sta GS 07, 16°08.43’N, 61°46.92’W, 12 m, 7. V.2012, MNHN-IU-2013-5597; 1♂ 1.3 mm, sta GS 07, [same station data], MNHN-IU-2013-5596; 1 ♀ 1.0 mm, Pointe à Lézard, sta GS 07, [same station data], MNHN-IU-2013-5598; 1♂ 1.2 mm, sta GS 07, [same station data], MNHN-IU-2013-5104; 1 ♂ 1.5 mm, 2 ♀ 0.9, 1.0 mm, sta GR 10, 16°08.43’N, 61°46.92’W, 29 m, 7. V.2012, MNHN- IU-2013-5022; 2 ♂ 1.2, 1.5 mm, 2 ♀ 1.0, 1.2 mm, 1 ovig ♀ 1.5 mm, sta GM 11, 1 m, 16°11.97’N, 61°34.28’W, 11. V.2012, MNHN-IU-2013-4852; 1 ♂ 0.9 mm, sta GB 13, 16°23.26’N, 61°31.79’W, 10 m, 14. V.2012, MNHN-IU-2013-5480; 1 ♂ 1.5 mm, sta GS 13, 16°02.4’N, 61°45.6’W, 50 m, 11. V.2012, MNHN- IU-2013-5252; 1 ovig ♀ 1.2 mm, sta GS 15, [same station data as holotype], MNHN-IU-2013-5450 ( USNM 1292075 ) ; 1♀ 1.0 mm, sta GB 16, 16°27.34’N, 61°32.07’W, 27 m, 16. V.2012, MNHN- IU-2013-5618 ( USNM 1292076 ) ; 1 ♂ 1.5 mm, 1 ovig ♀ 1.2 mm, sta GD 17, 16°12.55’N, 61°47.12’W, 30 m, 12. V.2012, MNHN- IU-2013-5629 ( USNM 1292077 ) ; 4 ♂ 0.7-1.5 mm, 1 ♀ 1.0 mm, sta GS 18, 16°23.74’N, 61°32.07’W, 49 m, 15. V.2012, MNHN- IU-2013-5233; 1♂ 1.2 mm, sta GB 19, 16°23.26’N, 61°31.79’W, 11 m, 17. V.2012, MNHN-IU-2013-5130; 2 ♂ 0.7, 1.2 mm, sta GS 19, 16°23.26’N, 61°31.79’W, 11 m, 17. V.2012, MNHN- IU-2013-5254; 1 ♂ 1.3 mm, sta GS 20, 16°27.34’N, 61°32.07’W, 19 m, 16. V.2012, MNHN-IU-2013-5453; 1 ♂ 1.2 mm, sta GS 21, 16°23.26’N, 61°31.79’W, 14 m, 16. V.2012, MNHN-IU-2013-4407; 1 ovig ♀ 1.0 mm, sta GB 30, 16°10.97’N, 61°32.41’W, 16 m, 25. V.2012, MNHN-IU-2013-5318.

ETYMOLOGY. — The species name “karukera” is that used by the Caribs or original inhabitants of the island currently known as Guadeloupe, where this new species was discovered. The Carib name roughly means “island with beautiful waters.”

DISTRIBUTION. — So far known only from the Caribbean island of Guadeloupe. Depth: 1- 80 m.

HABITAT. — Found in gastropod shells.

DESCRIPTION

Gills and shield ( Fig. 5A )

Eleven pairs of biserial phyllobranch gills. Shield ( Fig. 5A ) about as long as broad; anterior margin between rostrum and lateral projections weakly concave; anterolateral margins sloping or weakly terraced; posterior margin roundly truncate; dorsal surface smooth except for short row of tufts of setae anteriorly on either side of midline, and oblique row beginning at about midpoint of each lateral margin. Rostrum broadly rounded to obsolete.Lateral projections broadly subtriangular, terminating bluntly or with minute spine.

Ocular peduncles

About 0.8 length of shield; dorsal surfaces each with row of sparse tufts of short stiff setae, mesial surface of each peduncle with low knob bearing short stiff setae; corneas moderately dilated. Ocular acicles small, subtriangular, with concave dorsal surface; terminating bluntly and with small submarginal spine.

Antennular peduncles

Moderately long, exceeding distal margins of cornea when fully extended by about 0.3 length of ultimate segments. Ultimate segment nearly naked except for one or two long dorsodistal setae. Penultimate and basal segments naked.

Antennal peduncles

Slightly exceeding distal margins of corneas when fully extended. Fifth through third segments with scattered setae. Third segment with sparse tuft of stiff setae on blunt ventrodistal angle. Second segment sparsely setose; with dorsolateral distal angle produced into short spine-like process not quite reaching proximal margin of fourth segment; dorsomesial distal angle with short spine. First segment unarmed. Antennal acicle relatively short, reaching to about midline of cornea, broadly curving outward and terminating in strong spine, mesial margin with tufts of setae. Flagella long, overreaching tip of right cheliped; with few setae 1-2 flagellar articles in length and spaced every three or four flagellar articles.

Mouthparts ( Fig. 6 A-G)

Mandible ( Fig. 6A ) with 3-segmented palp. Maxillule ( Fig. 6B ) with internal lobe of endopod weakly produced, external lobe with long seta distally. Maxilla ( Fig. 6C ) with endopod slender, slightly shorter than distal lobe of basial endite but overreaching distal margin of scaphognathite. First maxilliped ( Fig. 6D ) with slender endopod, exopod with narrow proximal segment and thick flagellum. Second maxilliped ( Fig. 6E ) without distinguishing characters. Third maxilliped ( Fig. 6F, G ) with ischium armed basally with small spine; crista dentata weak, bearing about eight small subequal teeth in addition to two longer slender teeth distally, one strong accessory tooth.

Right cheliped ( Fig. 7A, B )

Chelipeds not much different in length, right stouter. Right cheliped with sparse setae often arranged in tufts. Dactyl 0.7- 0.8 length of palm, cutting edge with two or three widelyspaced, unequal, blunt calcareous teeth, row of minute corneous teeth distally, and terminating in small corneous claw slightly overlapped by tip of fixed finger; surfaces unarmed except for sparse setae and minute tubercle on mesial margin proximally. Fixed finger similar to dactyl, often slightly overreaching tip of dactyl. Palm about 1.2 times as long as carpus, dorsally unarmed except for sparse setae and row of small spines on dorsolateral and dorsomesial margins; ventral surface convex, nearly glabrous. Carpus about as long as merus; dorsal surface weakly convex, dorsodistal margin with small median spine; dorsolateral and dorsomesial margins each with somewhat irregular row of well spaced spines; lateral face rounded, mesial face flat, vertical; ventral surface rounded and with sparse setae. Merus subtriangular; dorsal, lateral and mesial surfaces with short transverse rows of tufts of setae, dorsodistal margin with small median spine; ventrolateral margin with small spine distally; ventral surface with distal row of setae and small distal spine. Ischium sparsely setose. Coxa unarmed except for row of setae on ventromesial distal angle.

Left cheliped ( Fig. 7C, D )

Reaching nearly to tip of fingers of right cheliped, moderately slender, similar to right in setation. Dactyl and fixed finger terminating in sharp, inwardly curved corneous claw slightly overlapping when close; surfaces with sparse setae; dactyl 1.2 times as long as palm; cutting edges with minute calcareous teeth and row of closely set corneous spinules on distal 0.75. Palm about 0.5 as long as carpus, dorsal surface with median, longitudinal row of minute well-spaced spines; lateral and mesial faces rounded, sparsely setose; ventral surface convex, unarmed except for sparse setae. Carpus slightly shorter to about as long as merus; dorsal surface somewhat flat, with dorsolateral and dorsomesial row of well spaced small spines; ventral surface convex, sparsely setose. Merus subtriangular; dorsal, lateral and mesial surfaces with short transverse rows of tufts of setae, dorsodistal margin with or without small median spine; ventrolateral margin with row of four or five spines, ventromesial margin with small distal spine. Ischium sparsely setose. Coxa unarmed except for row of setae on ventromesial distal angle.

Ambulatory legs ( Fig. 8A, B )

Exceeding tip of right cheliped by about 0.2-0.5 length of dactyls (exceeding right cheliped more in females than in males), dorsal and ventral margins of meri, carpi and propodi with well-spaced low knobs bearing long setae. Dactyls straight except for inwardly curved distal portion with sharp corneous claw, 1.3-1.6 as long as propodus, with ventromesial row of 5-7 long and slender corneous spinules; dorsal and ventral margins with few long setae. Propodi nearly straight, 1.3-1.7 as long as carpus; with scattered setae on lateral and mesial faces. Carpi usually each with small dorsodistal spine. Meri somewhat laterally compressed, lateral and mesial faces naked or with scattered short setae. Ischia with long setae on dorsal and ventral margins. Anterior lobe of sternite XI (of pereopods 3; Fig. 5B ) subsemicircular or subrectangular, with fringe of setae on distal margin.

Fourth pereopods ( Fig. 5C )

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

Fifth pereopods

Chelate. Propodal rasp occupying about one-third of distal surface of lateral face.

Telson ( Fig. 5D )

With distinct transverse lateral indentations; anterior lobes longer than posterior lobes, with few setae; posterior lobes nearly symmetrical, separated by broad and moderately deep median V-shaped cleft; terminal margins slightly oblique, with few setae, each with two or three small spines, usually a more prominent ventrally curved spine at lateral angle; lateral margins slightly rounded or nearly straight.

Sexual tubes ( Fig. 5E, F ) and pleopods

Males with long, often coiled, and distally filiform sexual tube produced from right coxa of pereopod 5, filiform portion often translucent and invisible except under high magnification; with short, conical sexual tube not distally filiform, produced from coxa of left pereopod 5. Females with pleopods 2-4 ovigerous, with few and relatively large eggs 0.3 mm in maximum width and ranging about 5-8 per pleopod; pleopod 5 not ovigerous, with reduced internal ramus.

Genetic data

See Table 1.

Colour

Unknown.

REMARKS

As for other species described in this report, individuals of Nematopaguroides karukera n. sp. are minute, ranging in size from 0.9-1.5 mm in shield length, and live in cryptic habitats of corals, rocks, or seagrasses ( Thalassia , Halophila ) near corals, where they appear to be abundant (28 specimens were collected). In some males the distal, filamentous portions of the sexual tubes on both sides are so delicate that they are easily broken off during processing, or can be completely transparent and easily overlooked.

When McLaughlin & Rahayu (2007b) transferred Nematopaguroides reconditus Wang & McLaughlin, 2000 to Pseudopagurodes McLaughlin, 1997 , they discussed the morphological differences between species of Nematopaguroides and Pseudopagurodes and evaluated the morphological justification to keep the two genera separate. They concluded that there is enough morphological evidence to justify the recognition of both genera. Nematopaguroides fagei , N. pusillus , and this new species indeed are sufficiently similar in morphology and geographic distribution (all three occur only in the western Atlantic) to support McLaughlin & Rahayu’s conclusion.

Nematopaguroides karukera n. sp. is most similar to N. pusillus , a western Atlantic species that rarely has been reported ( Lemaitre & Tavares 2015). The two can be differentiated by the shape of the rostrum (nearly obsolete in the new species vs obtusely triangular in N. pusillus ); the setation of ocular peduncles and pereopods 2 and 3 (low knobs with setae on mesial face of ocular peduncle and dorsal and ventral margins of meri, carpi and propodi of pereopods 2 and 3 in the new species vs lacking knobs in N. pusillus ); length and shape of dactyls of pereopods 2 and 3 (straight and about 1.3 times as long as propodi in the new species vs broadly curved and short, about 1.1 times as long as propodi in N. pusillus ).

Nematopaguroides karukera n. sp. can be separated from N. fagei by the shape and spination of the ventral margins of the dactyls of pereopods 2 and 3 (straight and with long spinules arranged at 45° angle in the new species vs broadly curved and with short spinules appressed against ventral margins or at most arranged at distinctly less than 45° in N. fagei ); the setose knobs on ocular peduncle and pereopods 2 and 3 (setation without knobs in N. fagei ); and armature of terminal margins of the posterior lobes of the telson (with weak spines in the new species vs strong, often curved spines in N. fagei ).

Figures

FIG. 5. — Nematopaguroides karukera n. sp., Guadeloupe: A, C-E: holotype ♂ 1.3 mm, sta GS 15, MNHN-IU-2013-5307; B, paratype ♂ 1.5 mm, sta GM 11, MNHN-IU-2013-4852; F, paratype ♂ 1.4 mm, sta GS 07,MNHN-IU-2013-5597; A, shield and cephalic appendages,dorsal view;B, sternite XI of third pereopods, ventral; C, propodus and dactyl of left fourth pereopod, lateral view; D, telson, dorsal view; E, F, sternite XIII and coxae of fifth pereopods with sexual tubes, ventral view. Scale bars: A, B, 0.5 mm; C-F, 0.25 mm.

FIG. 6. — Nematopaguroides karukera n. sp., holotype ♂ 1.3 mm, Guadeloupe, sta GS 15, MNHN-IU-2013-5307: left mouthparts, internal view: A, mandible; B, maxillule; C, maxilla; D, first maxilliped; E, second maxilliped; F, third maxilliped; G, ischium of same. Scale bars: 0.2 mm.

FIG. 7. — Nematopaguroides karukera n. sp., holotype ♂ 1.3 mm, Guadeloupe, sta GS 15, MNHN-IU-2013-5307: A, right cheliped, dorsal view; B, same, mesial view; C, left cheliped, dorsal view; D, same mesial view. Scale bar: 0.5 mm.

FIG. 8. — Nematopaguroides karukera n. sp., holotype ♂ 1.3 mm, Guadeloupe, sta GS 15, MNHN-IU-2013-5307: A, left pereopod 2, lateral view; B, left pereopod 3, lateral view. Scale bar: 0.5 mm.