Iridopagurus martinvaz, Lima & Tavares & Jr, 2019

Lima, Daniel, Tavares, Marcos & Jr, Joel Braga De Mendonça, 2019, Paguroids (Decapoda: Anomura: Diogenidae and Paguridae) of the remote oceanic Archipelago Trindade and Martin Vaz, off southeast Brazil, with new records, description of three new species and zoogeographical notes, Zootaxa 4694 (1), pp. 1-63 : 23-30

Iridopagurus martinvaz sp. nov.

( Figs. 10–14A )

Trindade and Martins Vaz specimens. HOLOTYPE: male sl 1.7 mm ( MZUSP 36199 ), Brazil, off Espírito Santo, Martin Vaz , stn 31/ DC 51 , 20°29’S, 28°53’W, M. Tavares coll., 20.v.1987, dredge, 48–52 m. PARATYPES: 1 ovigerous female sl 1.4 mm ( MZUSP 36200 ), off Espírito Santo, Trindade Island, Ponta da Calheta , 20°30’18.72”S, 29°18’31.67”W, J.B. Mendonça coll., 04.xi.2014, SCUBA, 16.9 m; 1 male sl 1.0 mm ( MZUSP 36198 ), Trindade Island , stn 35/ DC 59 , 20°37’37”S, 29°18’55”W, M. Tavares coll., 22.v.1987, dredge, 60 m ; 1 ovigerous female sl 1.9 mm ( MZUSP 38187 ), Trindade Island, Ponta da Calheta , J.B. Mendonça coll., 04.xii.2017, SCUBA, 17.2 m; 1 male sl 1.0 mm ( MZUSP 38188 ), Trindade Island, Ponta da Calheta , J.B. Mendonça coll., 24.xi.2017, SCUBA, 19.3 m; 1 female sl 1.9 mm ( MZUSP 38189 ), Trindade Island, Ponta da Calheta , J.B. Mendonça coll., 24.xi.2017, SCUBA, 19.3 m; 1 female sl 1.0 mm ( MZUSP 38190 ), Trindade Island, Ponta da Calheta , J.B. Mendonça coll., 24.xi.2017, SCUBA, 19.3 m; 1 juvenile female sl 0.8 mm ( MZUSP 38191 ), Trindade Island, Ponta da Calheta , J.B. Mendonça coll., 24.xi.2017, SCUBA, 19.3 m; 1 male sl 1.2 mm ( MZUSP 38192 ), Trindade Island, Ponta da Calheta , J.B. Mendonça coll., 24.xi.2017, SCUBA, 19.3 m; 1 male sl 1.2 mm ( MZUSP 38194 ), Trindade Island, Ponta da Calheta , J.B. Mendonça coll., 04.xii.2017, SCUBA, 17.2 m; 1 juvenile female sl 0.8 mm ( MZUSP 38195 ), Trindade Island, Ponta da Calheta , J.B. Mendonça coll., 24.xi.2017, SCUBA, 19.3 m; 1 male sl 0.8 mm ( MZUSP 38196 ), Trindade Island, Ponta da Calheta , J.B. Mendonça coll., 24.xi.2017, SCUBA, 19.3 m ; 1 ovigerous female sl 1.6 mm ( MZUSP 38197 ), Trindade Island, Ponta da Calheta , J.B. Mendonça coll., 24.xi.2017, SCUBA, 19.3 m .

Comparative material examined. Iridopagurus iris (A. Milne-Edwards, 1880) : 1 ovigerous female ( MZUSP 31861), Brazil, Espírito Santo, REVIZEE CENTRAL, stn VV31, 18°52’S, 39°35’W, 26.ii.1996, 22.8 m; 2 males ( MZUSP 36738), Rio de Janeiro, off Cabo Frio , REVIZEE—CENTRAL, stn D3, 22°52’S, 41°09’W, 23.xi.1996, 80.3 m; 1 ovigerous female ( MZUSP 13861 ), Uruguay, 34°38’S, 51°36’W, Projeto GEDIP, stn 465, 338 m.

Iridopagurus reticulatus García-Gómez, 1983: 1 male (USNM 102597), Cuba, Smithsonian—Roebling Exploring Expedition to Cuba, P. Bartsch coll. 08.iv.1937; 1 male ( MZUSP 36517 ), Brazil, Maranhão, R/V “Almirante Saldanha”, stn 1732, 02°15’S, 41°51’W, 30.x.1967, 52 m.

Type locality. Martin Vaz, 20°29’S, 28°53’W, off Espírito Santo, between 48–52 m, Brazil .

Distribution. So far known only from the Archipelago of Trindade and Martin Vaz, Espírito Santo, Brazil, between 17– 60 m.

Etymology. The specific epithet alludes to the type locality, Martin Vaz Archipelago, thus a noum in apposition and masculine.

Description. Eleven pairs of quadriserial gills. Shield ( Fig. 10A ) slightly longer than broad; dorsal surface with tufts of short setae near anterior margin. Anterolateral margin sloping. Anterior margin between rostrum and lateral projections concave. Posterior margin roundly truncate. Rostrum rounded, lacking spine. Lateral projections broadly triangular, each with one small marginal spine. Posterior carapace membranous; posteromedian plate with scattered tufts of short setae; branchiostergite with long setae anterolaterally.

Ocular peduncle ( Fig. 10A ) short, 0.5 length of shield, cylindrical, slightly dilated in corneal region; dorsomesial surface with tufts of short setae. Ocular acicle subtriangular, with 2 terminal spines, mesial spine more developed than lateral spine; mesial margin with moderately long setae; lateral margin with scattered short setae; separated by about basal width of 1 acicle.

Antennular peduncle ( Fig. 10A ) overreaching distal corneal margins by 1/3 length of ultimate segment. Ultimate segment long, dilated distally, with row of long setae distally arranged in V-configuration. Penultimate segment with scattered short setae on dorsal surface. Basal segment statosyst lobe with 1 spine on lateral margin and semicircular row of setae.

Antennal peduncle ( Fig. 10A ) reaching or slightly overreaching distal corneal margin. Fifth segment with scattered short setae on dorsal and ventral surfaces, moderately long setae on dorsal and ventral margins. Fourth segment with few, moderately long setae on ventral margin. Third segment with scattered short setae on ventral and mesial margins, ventrodistal margin without spines. Second segment with dorsolateral distal angle produced, terminating in simple spine, occasionally with 1 small submarginal spine; dorsomesial distal angle with small spine; dorsomesial and dorsolateral with scattered short and moderately long setae. First segment with three small spines laterally on ventrodistal margin. Antennal acicle reaching proximal corneal margin, but not overreaching distal corneal margin, curved outward, terminating in 1 strong spine; tip with tuft of long setae; mesial margin with scattered short setae. Antennal flagellum reaching tip of extended left cheliped, but not overreaching tips of P2 and P3; each article with 2–4 short setae, diminishing in length distally.

Mouthparts not dissected. Third maxilliped ( Fig. 10B ) basis unarmed, with moderately long setae, denser on mesial margin. Ischium with well-developed crista dentata consisting of row of 6–14 small, subequal corneous teeth, with scattered moderately long setae; accessory tooth absent. Merus with small spine on dorsodistal margin. Carpus, propodus and dactylus unarmed, with tufts of long, dense setae on ventral surfaces.

Chelipeds subequal, right stronger than left. Right cheliped ( Fig. 11A, B ) dactylus ( Fig. 11A, B ) 0.8 times as long as palm; dorsomesial margin bordered with small tubercles, dorsal surface proximally with cluster or short row of spinules or granules; mesial surface and dorsomesial margins with moderately long setae; cutting edge with 2 prominent calcareous teeth on proximal two-thirds, and distal row of small fused corneous teeth. Fixed finger with small calcareous tooth on proximal one-third and distal row of small calcareous teeth on cutting edge. Palm subretangular, 0.7 times as long as carpus; longitudinal row of small spines delimiting dorsolateral margin extending onto midlength of fixed finger; dorsal surface with 1 median row of small spines and sub-median irregularly longitudinal rows of spinules or granules; mesial surface with row of spinose tubercles, lateral and mesial surfaces with scattered short to moderately long setae. Carpus trapezoidal in cross section, slightly longer than merus, with short transverse rows of long setae on dorsolateral and dorsomesial margins; slightly inflated in ventral surface; lateral, mesial and ventral surfaces with scattered short to moderately long setae; dorsomesial margin with row of strong corneous spines; dorsolateral margin with 2–3 irregular rows of distal spines. Merus subtriangular; ventrolateral margin with 2 strong spines distally ( Fig. 11C ); ventromesial margin with 1 strong spine, preceded by row of tubercles. Ischium unarmed, with sparse setae. Coxa with 2 spines on ventrodistal margin, increasing in size laterally.

Left cheliped ( Fig. 12 A–C) with fingers leaving narrow hiatus when closed, terminating in small corneous claw respectively, crossed when closed. Dactylus slightly longer than palm, with row of minute spinules on dorsoproximal surface; longitudinal row of tubercles delimiting mesial margin diminishing in size distally; cutting edge with row of fused, small, corneous teeth. Fixed finger slightly overreaching dactyl; cutting edge with calcareous teeth interspersed with fused corneous teeth. Palm 0.7 times as long as carpus, near rectangular; dorsomesial margin with 2 rows of small spinules; dorsolateral margin with spaced rows of small spines; dorsal surface slightly convex, with irregular rows of minute spinules, reaching proximal margin of fixed fingers as 1 row; mesial and lateral surface with row of tubercles partially obscured by tufts of setae. Carpus trapezoidal in cross section, slightly longer than merus; slightly inflated ventrally; dorsomesial margin with row of strong spines distally, and row of tufts of moderately long and long setae; dorsolateral margin with 3 irregular rows of small spines, and rows of tufts of moderately long and long setae; ventrolateral distal angle with 1 strong spine; ventral, mesial and lateral surfaces with tufts of scattered short to moderately long setae. Merus subtriangular; dorsal and ventral margins with moderately long setae; lateral and mesial surfaces with scattered short setae; ventral margin with scattered spinose tubercles; ventromesial and ventrolateral margin with row of spines, increasing in size distally. Ischium with rows of small spines increasing in size distally, with row of moderately long setae. Coxa with 1 distal strong spine on ventrolateral angle, obscured by tuft of moderately long setae.

P2 and P3 much longer than chelipeds ( Fig. 12D, E ). P3 longer than P2, ornamentation similar from left to right. Dactyli long, 1.5 times as long as propodi; slender, curved, each terminating in sharp corneous claw; dorsomesial margin with row of moderately long plumose setae, reaching midlength, followed distally by row of long bristle-like setae reaching base of claw; mesial surface with row of short setae; ventromesial margin with row of moderately long plumose setae reaching about midlength of dactyli and with row of 2–4 corneous spines in distal half. Propodi 1.5–1.7 times as long as carpi; dorsolateral margin with row of tufts of short setae; dorsodistal margin with tuft of short setae; dorsomesial margin with row of plumose long setae, intercalated by few stiff setae; ventromesial margin distally with 1 small corneous spine. Carpi 0.5 times as long as meri; dorsal surface with 1–8 spines, diminishing in size proximally, with row of plumose long setae intercalated with few short stiff setae. Meri laterally compressed; dorsal surface with row of moderately long plumose setae; ventrolateral margin in P2 with row of short setae and small spine, absent in P3; ventral margin with moderately long setae, denser in P2; mesial surface of P2 with median proximal tuft of short setae, P3 glabrous. Ischia unarmed. Anterior lobe of sternite of P3 subretangular, slightly rounded, strongly skewed to left; anterior margin with 10 denticles, partially obscured by long setae.

P4 semichelate ( Fig. 11D, E ). Dactylus, curved, subtriangular, with 5–8 small teeth; preungual process absent; ventral margin with row of short setae; dorsosubdistal margin with tuft of moderately long setae, and scattered moderately long setae. Propodus with dorsodistal tuft of long setae and scattered moderately long and long setae on dorsal surface; propodal rasp consisting of 1 row of 7 evenly spaced, ovate corneous scales, increasing in size distally, occupying to about two-thirds of ventral margin.

P5 weakly subchelate. Propodal rasp dorsally extending for about half surface of propodus.

Adult males with left sexual tube long, coiled, directed externally. Right sexual tube short, directed externally ( Fig. 10C ). Unpaired Pl3–Pl5, third to each with exopodite well developed, endopodite reduced. Females with unparied Pl2–Pl5; exopodite more developed than endopodite.

Uropods markedly asymmetrical, left largest.

Telson asymmetrical ( Fig. 10D ), with transverse indentation; posterior lobes separated by moderately deep, Ushaped, median cleft; terminal margins oblique, each armed with several small spines; lateral margin smooth, with narrow chitinous plate.

Color. In life ( Fig. 13 A–D), shield with many small white spots on a light brown background, extending to posteromedian plate and posterior branchiostergite; shield and posteromedian plate with with 2 pairs and 1 pair of reddish orange spots, respectively; branchiostergite deep red anteriorly. Corneas light brown. Ocular peduncle with minute white spots on a whitish background dorsally, ringed with deep red distally, dull orange subproximally. Antennular basal segment reddish-orange with minute white spots. Chelipeds pearly white; lateral surface of fixed fingers and dorsal surface of propodi each with red-orange patch proximally. Carpus ringed with a deep red, transversal, narrow band subdistally and a red, short band subproximally on the mesial surface only. Dorsal and mesial surfaces of meri with a deep red, transversal, incomplete, narrow band subdistally. Dactyli of the P2 and P3 narrowly ringed with red-orange subdistally on a blueish background. Propodi whitish distally, blueish on proximal two-thirds and four light brown dorsal patches. Carpi and meri whitish distally, with longitudinal, parallel, light brown bands on a blueish background; brown bands almost as long as carpi, limited to the distal half of merus. Meri whitish proximally.

Remarks. The American genus Iridopagurus comprises nine species, seven of which are Atlantic in distribution: I. caribbensis (A. Milne-Edwards & Bouvier, 1893) , I. dispar ( Stimpson, 1859) , I. iris (A. Milne-Edwards, 1880) , I. globulus de Saint Laurent-Dechancé, 1966; I. margaritensis García-Gómez, 1983 , I. reticulatus García- Gómez, 1983, and I. violaceus de Saint Laurent-Dechancé, 1966.

Within the Atlantic American Iridopagurus , the closest morphological affinity of I. martinvaz sp. nov. is with I. reticulatus , to which it superficially resembles in having the anterior lobe of the sternite of P3 roundly rectangular ( Fig. 10C ) (see also García-Gómez 1983: fig. 3H). However, I. martinvaz sp. nov. can be separated from I. reticulatus in having 1) the dorsal surface of the right cheliped with 1 median row of small spines and sub-median irregular rows of spinules, Fig. 11A (vs. dorsal surface of right cheliped with few irregular rows of short spines); 2) chelipeds pearly white with the lateral surface of the fixed fingers and dorsal surface of the propodi with a red-orange patch proximally, and carpus ringed with a deep red, transversal, narrow band subdistally, Fig. 14A (vs. dorsal surfaces of palms and carpi reticulated with brown in I. reticulatus , Fig. 14B ); 3) ocular peduncles whitish dorsally, ringed with deep red distally and dull orange subproximally, Fig. 13 A–D (vs. ocular peduncles brown dorsally, ringed with dull orange only subproximally in I. reticulatus , Fig. 14B ); 4) telson with posterior lobes separated by shallow, Ushaped, median cleft, Fig. 10D (vs. deep median cleft in I. reticulatus , see García-Gómez 1983).

Iridopagurus reticulatus does occur in the Brazilian coast. Coelho et al. (1983) first recorded it as I. dispar , based on a single specimen from Porto de Pedras, Alagoas (~ 09°S). Later, that specimen was re-identified by Coelho et al. (1990) as I. reticulatus . Nucci & Melo (2011) accepted the identification of the specimen from Alagoas (MOUFPE 3671; ex-DOUFPE 3671) with I. reticulatus . This, however, cannot be confirmed by us as that specimen no longer exists in the collections of the MOUFPE (J. Fidelis, pers. com.).

Nucci & Melo (2011) extended the distribution of I. reticulatus further south based on the female MZUSP 13877 from Santa Catarina (~ 27°S). However, the present re-examination of the specimen MZUSP 13877 revealed that it could not be attributed to Iridopagurus as it lacks the diagnostic quadriserial gills of the genus (the specimen from Santa Catarina has biserial gills instead) and has an accessory tooth near to the crista dentata (species of Iridopagurus have no accessory teeth near the crista dentata). No generic assignment for the female MZUSP 13877 has been attempted at this point because it has no paired first pleopods modified into gonopods and its right cheliped and P4 have been lost.

In the MZUSP collections there is one male from Maranhão (~ 02°S) (MZUSP 36517), which we tentatively identify with I. reticulatus . Hence, from the available evidence, along the Brazilian coast I. reticulatus is only known from Maranhão and Alagoas.

Iridopagurus martinvaz sp. nov. differs from I. dispar and I. iris in having the chelipeds moderately spinose and the left cheliped merus distodorsal margin without spines, respectively (vs. chelipeds smooth in I. dispar , and left cheliped merus with a strong spine on the distodorsal margin in I. iris ).

The new species can be split from I. globulus in that the right cheliped palm is distinctly spinose on the dorsolateral margin, and by the lack of a bundle of fine setae at the base of the corneous claw of P4, whereas in I. globulus the right cheliped palm dorsolateral margin is inermis, and the base of the P4 corneous claw is provided with a distinct bundle of fine setae—referred to as “preungual process type I” by García-Gómez 1983).

Iridopagurus martinvaz sp. nov. can be easily distinguished from I. caribbensis in having the anterior lobe of the sternite of P3 roundly rectangular, Fig. 10C (whereas in I. caribbensis it is subsemicircular) and in that the antennal acicle falls much short of the distal margin of the cornea, Fig. 10A (whereas in I. caribbensis it extends far beyond the distal margin of the cornea).

It differs from I. margaritensis and I. violaceus in having the P3 sternite anterior lobe roundly rectangular ( Fig. 10C ), and the P4 and P5 sternites each with a transversal row of simple setae, respectively, Fig. 10C (vs. P3 sternite anterior lobe subsemicircular in I. margaritensis , and P4 and P5 sternites each with a transversal row of stiff setae in I. violaceus ).

Figures

FIGURE 10. (A–D) Iridopagurus martinvaz sp. nov., male holotype, sl 1.7 mm (MZUSP 36199). (A) shield and cephalic appendages, dorsal view. (B) right and left third maxilliped, respectively, ventral view. (C) sternites XII–XIV and coxae of P5 with sexual tubes, ventral view. (D) Telson, dorsal view. Scale bars: A–C, 1.0 mm; D, 0.5 mm.

FIGURE 11. (A–E) Iridopagurus martinvaz sp. nov. (A–C, E) male holotype, sl 1.7 mm (setae partially omitted) (MZUSP 36199). (D) male paratype, sl 1.0 mm (MZUSP 36198). (A) right cheliped, dorsal view. (B) right cheliped, mesial view. (C) right cheliped, lateral view. (D, E) dactylus, propodus and carpus of left P4, lateral view. Scale bars: A–C, 1.0 mm; D, E, 0.25 mm.

FIGURE 12. (A–E) Iridopagurus martinvaz sp. nov., male holotype, sl 1.7 mm (setae partially omitted) (MZUSP 36199). (A) left cheliped, dorsal view. (B) left cheliped, lateral view. (C) left cheliped, mesial view. (D) left P2, mesial view. (E) third right pereopod, mesial view. Scale bars: 1.0 mm.

FIGURE 13. (A–D) Iridopagurus martinvaz sp. nov. (A, B) ovigerous female paratype, sl 1.4 mm (MZUSP 36200). (C, D) female paratype, sl 1.9 mm (MZUSP 38189). Photographs by J.B. Mendonça Jr.

FIGURE 14. (A) Iridopagurus martinvaz sp. nov., male paratype, sl 0.8 mm (MZUSP 38196). (B) Iridopagurus reticulatus (García-Gómez, 1983) from Saint Martin Island. Photographs by J.B. Mendonça Jr. (A) and J. Poupin and L. Corbari (B).