Paguristes karenae, Craig & Felder, 2022

Craig, Catherine W. & Felder, Darryl L., 2022, Two new marine hermit crabs allied with the Paguristes tortugae complex (Crustacea: Decapoda: Anomura) from the western Atlantic, Zootaxa 5178 (1), pp. 1-25 : 13-20

Paguristes karenae n. sp.

( Figs 5B , 6–8 )

Paguristes tortugae . — Provenzano, 1959: 389, 392 (part, green carapace with red spines on cheliped carpus and manus inner margins), fig. 11A; Williams, 1965: 115, 119 (part, green carapace with red spines on cheliped carpus and manus inner margins, not fig. 96); McLaughlin & Provenzano, 1974 (part, “darker forms”); Williams, 1984: 205, fig. 144 (USNM 151492); Wicksten, 2005: 34, table 1 (part, uncertain identification suggested, footnote 20); Venera-Pontón et al., 2020, 4, table 1 (part, ULLZ 13663, 13665, 13707, 13708).

Paguristes sp. — Strasser & Price, 1999: 34, 41.

Paguristes nr. tortugae .— Craig & Felder, 2021: table 1, 307, 311, 316, 317.

Paguristes “nr. tortugae nov. sp. ”.— Craig & Felder, 2021: fig. 1, 312

Type material. Holotype: male DNA and photo voucher, sl 5.6 mm ( ULLZ 4782 / USNM 1540546 ), Florida Keys, Pigeon Key , Florida, 09 June 2001, coll. K. Strasser (Barkel).

Paratypes: Florida Atlantic coast and Keys: 1 female photo voucher, sl 3.2 mm ( ULLZ 5647 / USNM 1542520 ), off Ft. Pierce , Florida, 15m, 09 Sep 2003 ; 1 male photo voucher, sl 6.1 mm, 1 male, sl 3.4 mm ( ULLZ 12171 / USNM 1546239 ), Big Pine Key, Boogie Canal , scallop dredge, 2–3 m , 07 Jul, 1979; 1 male photo voucher, sl 6.3 mm ( ULLZ 15244 / USNM 1548287 ) Content Keys , dredge, 2–4 m, 27 Jun 1984 ; 1 male photo voucher, sl 5.6 mm, 1 male, sl 4.3 mm ( ULLZ 15245 / USNM 1548289 ), Big Pine Key, Newfoundland Harbor , dredge, 2–4 m, 25 Jun 1984 ; 1 male DNA voucher, sl 5.9 mm ( UF 015380), Tampa Bay , 4 km West of Sunshine Skyway, spoil heap with sponges, 6–7 m, 07 Feb 2009 .

Northeastern Gulf of Mexico: 2 males, DNA and photo vouchers, sl 3.9, 4.9 mm ( ULLZ 8578 / USNM 1543769 ), cruise NSF-III-055, 28°10.28’N, 84°1.95’W, 41 m, 04 Jul 2006 .

Belize. 1 female DNA and photo voucher, sl 3.0 mm , 1 female sl 2.0 mm ( ULLZ 11116 / USNM 1545590 ), Twin Cays, rubble, 20 Feb 2009 ; 1 male photo voucher, sl 4.2 mm ( ULLZ 3563 / USNM 1540063 ), Carrie Bow Cay, 1 m, 20 Apr 1983 .

Panama ( Caribbean ): 1 ov female DNA voucher, sl 3.4 mm ( ULLZ 13664 / USNM 1547025 ), Bocas del Toro, 09°21.060’N, 82°15.540’W, grass beds and Porites , 2 m, 08 Aug 2011; 1 male DNA voucher, sl 4.7 mm ( ULLZ 13663 / USNM 1547024 ), Bocas del Toro, 09°21.060’N, 82°15.540’W, grass beds and Porites , 2 m, 08 Aug 2011; 1 male DNA voucher, sl 4.2 mm ( ULLZ 13665 / USNM 1547026 ), Bocas del Toro, 09°21.060’N, 82°15.540’W, grass beds and Porites , 2 m, 08 Aug 2011; 1 male DNA and photo voucher, sl 3.60 mm, ( ULLZ 16969 / USNM 1665635 ), Bocas del Toro, stn. 8, Almirante pilings, 9°16.218’N, 82°23.382’W, SCUBA, 1.5 m, 03 Aug 2004; 1 male DNA and photo voucher, sl 3.80 mm, ( ULLZ 16975 / USNM 1665638 ), Bocas del Toro, stn. 19, 05 Aug 2004; 1 male DNA and photo voucher, sl 2.60 mm ( ULLZ 13330 / USNM 1546874 ), Bocas del Toro, 07 Aug 2011; 1 male DNA and photo voucher, sl 3.6 mm ( ULLZ 11743 / USNM 1545935 ), Bocas del Toro, stn. 36, Cayo Adriana, 9°14.456’N, 82°10.413’W, 09 Aug 2004; 1 male photo voucher, sl 3.75 mm, ( ULLZ 16976 / USNM 1665637 ), Bocas del Toro, stn. 35, Bastimentos, 9°21.052’N, 82°15.340’W, 06 Aug 2004 .

Other material: Florida Atlantic coast and Keys: 1 female photo voucher, sl 3.0 mm ( ULLZ 469 / USNM 1542655 ), 2 km southeast of St. Lucie Inlet , 0.7–10 m, 26 June, 1979; 1 ov female, sl 4.0 mm ( UF 031583) Big Bend area, northwest of St. Petersberg , hard bottom, sponge reef, 29–30 m, 23 May 2012; 1 male, sl 3.3 mm ( ULLZ 17737 / USNM 1665636 ) , Florida Bay, Rabbit Key Basin , 09 Dec 1998; 2 ov females, sl 3.8, 3.9 mm, 2 males, sl 4.5, 3.5 mm ( ULLZ 11544 / USNM 1545758 ) , Florida Bay, eastern Rabbit Key Basin, Thalassia beds, 1.5 m, 22 Jul 1999; 1 male, sl 4.1 mm ( ULLZ 14019 / USNM 1547351 ), Big Pine Key , coral heads, 0.6–6 m, 03 Jul 1979; 1 ov female, sl 5.2 mm ( ULLZ 9859 / USNM 1544679 ), Looe Key area XI, 24°32.910’N, 81°24.355’W, gorgonian reef, rubble and sponges, SCUBA, 6–7 m, 22 Jun 1984 .

Southwestern Gulf of Mexico: 4 males, sl 3.68, 4.55, 4.00, 3.25 mm, 1 female, sl 4.05 mm ( ULLZ 11745 / USNM 1545937 ), Tamaulipas , off Barra del Tordo, 19 Aug 1979 ; 1 unsexed juvenile, sl 1.5 mm, 3 ov females, sl 4.1, 3.6, 5.1 mm, 1 female, sl 3.4, 4 males, sl 2.7, 2.6, 4.3, 5.4 mm, ( ULLZ 239 / USNM 1538562 ), Campeche , Isla Aguada, Laguna de Terminos, Thalassia beds, 05 Jan 1978 ; 1 male, sl 11.5 mm ( ULLZ 88 / USNM 1542715 ), Campeche , northeast of Champoton, grass beds, 07 Jan 1978 ; 1 female, sl 4.4 mm, 1 male, sl 4.1 mm ( ULLZ 230 / USNM 1542740 ), Campeche , 5 miles north of Seybaplaya, 06 Jan, 1977; 1 ov female, sl 3.9 mm , 1 male, sl 5.6 mm ( ULLZ 93 / USNM 1542718 ), Campeche , 5 miles north of Seybaplaya, intertidal rocks, corals, and sponges, 06 Jan 1977 .

Panama. 1 male, sl 4.0 mm ( ULLZ 13707 / USNM 1547066 ), Bocas del Toro, grass beds and Porites , 2 m, 08 Aug 2011 ; 1 male, sl 3.7 mm ( ULLZ 13708 / USNM 1547067 ), Bocas del Toro, 08 Aug 2011, grass beds and Porites , 2 m .

French Antilles. 1 male, sl 2.5 mm ( UF 032561), Saint Martin, Caye Verte , reef with sand and seagrass, 1–3 m, 25 Apr 2012 .

Diagnosis. Antennal flagellum slender with sparse setae 1–3 articles in length near joints of articles.Antennular peduncles not exceeding corneas, or exceeding corneas by less than 0.5 distal length of ultimate segment. Ocular peduncles subcylindrical, slightly narrower near midlength, always marked with distinct dark bands near midlength bordered by white distally and proximally, (often persisting in ethanol preserved specimens). Ocular acicles well separated by rostrum, with narrow anterior projection bifid or multifid, bearing a variable number of accessory spines laterally. Rostrum tapering evenly to an acute point. Cheliped manus dorsomesial margin bearing 3 strong, corneous-tipped spines. Cheliped carpus dorsomesial margins with 4 or 5 strong, corneous tipped, conical spines, color bright carmine red in life. Second pereopod carpus dorsal margin with row of acute spines and third pereopod carpus dorsal margin with 1 or more acute spines distally, bright carmine red in life. First maxilliped with epipod well developed. In life, carapace shield with patches of olive green to light brown, pereopods two and three with light brown to olive green background color, branchiostegites laterally translucent purple with some white spotting. Applicable GenBank sequence accession numbers from Craig & Felder (2021) are as follows for holotype, ULLZ 4782/USNM 1540546: (H3) MW160343 ; (12S) MW160976 ; (16S) MW167246 .

Description. Thirteen pairs of biserial gills. Shield ( Fig. 6A, B ) sub-triangular, length approximately 1.4 times width. Dorsal surface central region convex; lateral surfaces bearing irregularly spaced small tubercles, spinules, and spines interspersed with sparse setae; anterior margins between rostrum and lateral projections distinctly concave, paralleled by well-defined marginal ridge; anterolateral angle obtuse and rounded bearing numerous irregularly spaced spines and spinules. Rostrum triangular, extending anteriorly beyond lateral projections, lateral margins sloping evenly to acute point and bearing fringe of setae. Lateral projections acute. Branchiostegite lateral surface with granular texture nearly obscured by tufts of long setae. Posterior carapace poorly calcified, lateral surfaces bearing scattered setae.

Ocular peduncles ( Fig. 6A ) subcylindrical, slightly narrower at midlength, diameter at base approximately equal to that of cornea, left longer than right; dorsomesial surface bearing tufts of long setae proximally. Ocular acicles ( Fig. 6A ) subtriangular, mesial borders unarmed and separated by rostrum; anterior projection bifid or multifid, lateral margin bearing 1 or more acute spines.

Antennular peduncles ( Fig. 6A ) not extending anteriorly beyond cornea distal margin in holotype (exceeding cornea distal margin by approximately 0.5 length of ultimate segment in some paratypes); basal segment lateral surface bearing small spine.

Antennal peduncles ( Fig. 6A ) not extending anteriorly beyond cornea distal margin. Fifth segment without remarkable characteristics. Fourth segment dorsodistal angle bearing anteriorly angled spine. Third segment ventromesial distal angle bearing strong spine, somewhat obscured from dorsal view by dense fringe of setae. Second segment dorsolateral distal angle forming anterior projection terminating in single spine, lateral margin somewhat oblique, bearing 3 spines, dorsomesial distal angle bearing single spine. First segment dorsolateral distal angle bearing minute spine. Antennal acicles extending slightly beyond 0.5 mid-length of ocular peduncle, terminating in single spine; lateral margin bearing 2 or more spines (number variable among paratypes) interspersed with tufts of long setae; mesial border with 1 or more (number variable among paratypes) widely spaced spines partially obscured by dense fringe of setae. Antennal flagellum not extending beyond fingertips, sparse setae approximately 1–3 articles in length at joints of flagellar articles.

Mandible ( Fig. 6F ) with incisor edge calcareous; ultimate segment of palp broad, setose, length equal to combined length of penultimate and basal segments. Maxillule ( Fig. 6E ) proximal and distal endite mesial margins densely setose; endopod internal lobe distal angle bearing sparse tuft of bristles, external lobe recurved, length approximately 0.7 times that of internal lobe, terminal angle bearing sparse setae. Maxilla ( Fig. 6C ) proximal and distal endite mesial margins densely setose; endopod tapered distally, not overreaching distal apex of scaphognathite; scaphognathite recurved, margins densely setose. First maxilliped ( Fig. 6D ) proximal and distal endite mesial margins densely setose; endopod length approximately 0.7 times that of exopod; exopod tapering distally, lateral margin densely setose, flagellum elongate and densely setose; epipod well developed, margins densely setose. Second maxilliped ( Fig. 6H ) basis mesial margin bearing small blunt spine. Third maxilliped ( Fig. 6G, I ) endopod merus external surface bearing 2 or more strong, curved spines on mesial margin; ischium external surface distomesial angle bearing 1 spine; crista dentata well developed, lacking accessory tooth.

Chelipeds ( Fig. 7A–D ) subequal in size, similarly armed, opening transversely; dorsal surfaces of chelae and carpi densely covered with tufts of plumose setae partially obscuring armature beneath, longer setae forming dense fringe along dorsolateral and dorsomesial margins of chelae and carpus; both fixed and moveable finger with distal extremity terminating in hoof-like corneous claw. Dactyl length approximately 2.5 times maximum height; cutting edge bearing calcareous teeth decreasing in size distally and widely spaced tufts of stiff bristles; dorsal surface bearing irregularly spaced low tubercles and conical spines, many abutting tufts of setae or stiff bristles; dorsomesial surface bearing scattered low tubercles, each abutting tuft of setae; ventral surface cutting edge paralleled by longitudinal groove bearing widely spaced tufts of stiff bristles. Fixed finger not extending beyond moveable finger; cutting edge bearing numerous blunt calcareous teeth and scattered tufts of setae. Palm dorsal surface somewhat convex, bearing densely distributed conical tubercles and spines, some with corneous tips, most abutting tuft of setae (setae largely obscuring armature for most paratypes); dorsomesial margin well defined, bearing 3 conical spines with corneous tips; dorsolateral margin bearing row of numerous irregularly spaced conical spines, some with corneous tips; ventral and lateral surfaces bearing scattered low tubercles (blunt spines or conical tubercles in some larger paratypes) many abutting tufts of short setae. Carpus length approximately 0.5 times that of chela; dorsal surface midline bearing irregularly distributed conical spines interspersed tufts of setae; dorsomesial border well defined, armed with 4 (5 in some paratypes) conical spines with corneous tips, bright carmine red color in life; dorsolateral margin bearing continuous row of conical spines, some with corneous tips; dorsodistal margin with slight anterior projection near midline bearing small conical spines (number variable among paratypes) somewhat obscured by dense setae; lateral and mesial surfaces relatively smooth, setation sparse; ventrodistal angle forming hook-like projection bearing 1 or more small spines at distomesial extremity. Merus length approximately 2 times that of carpus, subtriangular in cross section; dorsal margin bearing irregularly spaced small spines proximally, transected subdistally by low ridge bearing conical spines, some with corneous tips; dorsodistal margin bearing conical spines near midline, some with corneous tips; mesial surface relatively smooth; ventromesial margin bearing row of conical spines distally; ventrolateral margin surface bearing row of irregularly spaced spines interspersed with long setae. Ischium mesial surface subtriangular; ventromesial margin bearing minute spines or spinules; ventrodistal margin bearing sparse tufts of setae. Coxa distal margin bearing dense fringe of setae; ventral surface densely setose.

Second pereopod ( Fig. 7E, F ) extending beyond cheliped by approximate length of second pereopod dactyl when both fully extended, terminating in single corneous claw, segments somewhat laterally compressed; dorsal margins of dactyl, propodus, carpus, and merus bearing dense fringes of setae obscuring underlying armature for many paratypes; ventral margins likewise. Dactyl length approximately 5.5 times maximum height, curved ventrally from lateral view, terminating in curved corneous claw with enlarged spine and tuft of stiff bristles proximally; dorsal and ventral margins each bearing row of corneous-tipped spines (minute in smaller paratypes), increasing somewhat in size distally, observable at high magnification from mesial view; mesial surface bearing scattered small corneous spines (more prominent and often broadly distributed in larger paratypes). Propodus length approximately 0.7–1.0 times that of dactyl (ratio slightly variable in paratypes); dorsal margin bearing row of spines somewhat obscured by dense fringe of setae (in mesial view); mesial and lateral surfaces armed with series of low transverse ridges each bearing small spinules (visible in holotype and larger paratypes); and abutting row of setae. Carpus length approximately 0.7 times that of propodus; dorsal margin armed with numerous (number varies among paratypes) conical spines with corneous tips, color deep carmine red in life; dorsolateral surface with pronounced longitudinal ridge bearing dense tufts of long setae; dorsomesial surface bearing tufts of setae arranged in transverse rows. Merus length approximately 2 times that of carpus; dorsal margin bearing dense fringe of setae arranged in a series of transverse rows; ventral margin bearing row of widely spaced conical spines (in mesial view); ventrolateral surface bearing scattered tufts of short setae; distolateral margin bearing conical spines distally (number and prominence varies among paratypes). Ischium mesial and lateral surfaces subtriangular. Coxa without distinguishing characters.

Third pereopod ( Fig. 8A, B ) not extending beyond claw of second pereopod, similar in proportion and armature to second pereopod except as noted here. Dactyl mesial surface bearing numerous corneous spines, more prominent and broadly distributed than those of second pereopod. Propodus mesial surface more tubercular and setose than that of second pereopod for most paratypes. Carpus dorsal margin with conical, corneous tipped spines restricted to distal 0.5; dorsodistal angle bearing somewhat enlarged conical spine. Merus lateral surface slightly convex; dorsolateral surface bearing series of transverse rugae; mesial surface bearing elongate oblique rugae. Ischium length approximately 0.5 times that of merus; mesial and lateral surfaces subrectangular. Sternite of third pereopod subrectangular, left and right each bearing rounded tubercle with dense tuft of setae.

Fourth pereopod ( Fig. 8D ) laterally compressed, not extending beyond distal margin of third pereopod merus. Dactyl ( Fig. 8E ) robust, terminating in curved corneous claw dense tuft of setae dorsally; dorsal margin bearing tufts of stiff bristles; ventrolateral surface bearing 1–3 stout teeth interspersed with bristles, most distal tooth somewhat enlarged and abutting base of preungal process. Preungal process well-developed, length slightly less than that of corneous claw. Propodus length approximately 2 times that of dactyl; dorsal margin bearing long setae distally; ventrolateral surface bearing oblong rasp extending approximately 0.7 distal length of segment. Carpus, merus, and ischium similar in length, dorsal and ventral margins of each bearing dense fringe of setae.

Fifth pereopod ( Fig. 8F ) chelate, with length of fixed finger subequal to that of dactyl; segments generally subcylindrical. Propodal rasp continuous across dactyl, fixed finger, and approximately 0.3 distal length of segment; ventromesial surface bearing dense patch of setae. Carpus somewhat recurved; dorsal margin bearing sparse setae. Merus lateral surface bearing irregular longitudinal row of setae near midline. Coxa lateral surface bearing dense tuft of setae and male sexual pore proximally.

Abdomen curled, poorly sclerotized. Male first ( Fig. 8G, H ) and second pleopods paired and modified as gonopods, pleopods 3–5 unpaired; first pleopod inferior lamella ( Fig. 8G ) lateral margin bearing fringe of setae, distal margin with numerous irregular rows of curved teeth extending onto external surface, internal lamella distal margin bearing fringe of long setae, external lamella extending slightly beyond inferior lamella of distal margin; basal segment of second pleopod bearing sparse tuft of long setae at superior mesial angle. Female first pleopods paired, pleopods 2–5 unpaired, pleopod 5 uniramous; paired gonopores on coxa of third pereopod; brood pouch large, subovate to subquadrate; eggs approximately 0.5–0.7 mm in diameter.

Uropods ( Fig. 8I ) strongly asymmetrical, left robust and elongate. Telson ( Fig. 8I ) weakly asymmetrical, left lobe somewhat larger than right, deep lateral incisions dividing anterior and posterior portions; anterior lobes subovate to subtriangular, distolateral angles each bearing 1 or more (number variable in paratypes) conical spines; posterior lobes subtriangular, left and right separated by well defined cleft, terminal margins each bearing scattered bristles and numerous conical spines, some with corneous tips (number, prominence, and precise orientation of spines variable in paratypes).

Size. Largest examined, male, sl 11.5 mm.

Color. Carapace shield with patches of olive green to light brown, pereopods two and three with light brown to olive green background color, branchiostegites laterally translucent purple with some white spotting, ocular peduncles with distinct dark brown to almost black bands near midlength (bands often persisting in preservation as dark pink to orange) bordered with white both proximally and distally ( Fig. 5B ). Spines on cheliped carpus dorsomesial margins bright carmine red with corneous tips. Spines on third pereopod carpus dorsal margin bright carmine red.

Etymology. The species name, “karenae”, honors our colleague and friend, Karen Barkel (formerly Strasser), for reknown contributions to studies of decapod crustaceans, collections that assisted our efforts, and persistent urging that this new species be formally described.

Distribution and habitat. Broadly distributed across the Gulf of Mexico, eastern coast of South America, southeastern and southwestern Caribbean, and along the eastern coast of Florida; bathymetric distribution ranging between the intertidal zone and approximately 30 m in depth. Collected in arange of habitats including hard-bottom substrates, rubble, sandy bottoms with seagrass ( Thalassia ), reef communities, sponges, and coral ( Porites ).

Morphological variations. Paguristes karenae n. sp. shows a moderate range of intraspecific variation related to specimen size. Zones of spination are characteristic of the species, but within those zones, larger specimens exhibit fewer, more robust spines, especially on the ambulatory appendages. There are exceptions, however, as in the case of the third pereopod dactyl mesial surface, where larger individuals show a broad distribution of corneous spines with moderate prominence, compared to the scattering of minute spines seen in most smaller individuals. In addition to variability of spination related to size, eyestalk shape shows some variance, with the eyestalks of smaller specimens tending to have a broader proximal base relative to the cornea, accompanied by a greater taper at midlength when compared to the eyestalks of larger individuals.

Two notable morphological variations seemingly unrelated to size can be found among paratypes. In both large and small individuals, the cheliped carpus dorsomesial margin is typically armed with four prominent red spines, but for some paratypes there is a moderately sized fifth accessory spine at the base of the fourth most distal spine. In addition, antennular peduncle length relative to that of the eyestalk varies, with the antennular peduncle exceeding the cornea distal margin for some paratypes.

Remarks. Although the occurrence of P. tortugae in the northern Gulf of Mexico was once considered tentative ( McLaughlin & Provenzano 1974), numerous records based on ULLZ collection data confirm its occurrence throughout the Gulf of Mexico and Caribbean over a range of depths ( Table 1 ), as suggested previously by Felder et al. (2009: footnote 200, 1096). Collection data for P. karenae n. sp. specimens available to us indicate that the geographic and bathymetric distributions of P. karenae n. sp. approximate those of P. tortugae . This is evident even at very local scales, with examples of P. tortugae and P. karenae n. sp. specimens housed at USNM (including many recently accessioned from ULLZ) collected from overlapping localities and similar habitats. Despite this sympatry, consistent differences in color between the two species, along with corresponding morphological characters, provide support for their separation, and molecular phylogenetic analysis confirms the two as distinct sister lineages ( Craig & Felder 2021).

McLaughlin & Provenzano (1974) cited color and pattern as diagnostic of at least five of the original constituent species of the P. tortugae complex. Historically, accounts detailing the color of P. tortugae itself established two color forms, both of which possess eyestalks bearing dark bands bordered by white near midlength ( Wass 1955; Holthuis 1959; Provenzano 1959, 1965; Williams 1965; McLaughlin & Provenzano 1974; Strasser & Price 1999). Photographic evidence compiled by us in the course of long-term decapod biodiversity surveys in the western Atlantic corroborates literary accounts of these two sympatric color forms, both of which are morphologically consistent with existing diagnosis of P. tortugae sensu McLaughlin & Provenzano (1974) . In our photographic accounts, specimens with a whitish to light purple background color ( Fig. 5A ) are considered herein to correspond to Schmitt’s (1933) P. tortugae , a form earlier documented as having a relatively light coloration ( Provenzano 1959; Williams 1965; McLaughlin & Provenzano 1974) with rosy to somewhat purple walking legs ( Holthuis 1959; Provenzano 1965). The second color form, described in the present work as P. karenae n. sp. ( Fig. 5B ), has an overall light brown to olive green carapace, as well as distinctly red spines on the carpi of the walking legs, particularly the mesial margin of the manus and carpus of the cheliped. This coloration had been previously observed by other authors ( Provenzano 1959; Holthuis 1959; Williams 1965), and is considered herein to correspond to the “darker” forms of McLaughlin & Provenzano (1974).

Despite their overall similarity to one another, morphological differentiation of Paguristes tortugae and P. karenae n. sp. can be made by considering the precise shape of the rostrum. For both species, the rostrum is well developed, extending past the lateral projections of the shield and separating the ocular acicles. However, in P. karenae n. sp. the rostrum tapers evenly to an acute point ( Fig. 6A ), whereas that of P. tortugae exhibits slightly rounded shoulders to either side of the rostrum apex ( Fig. 6B ). Inclusion of USNM 151492 in our synonymy of P. karenae is based on this criterion, with Williams (1984: fig 144) showing clearly a triangular and evenly tapered rostrum. In addition to its distinct rostral taper, oblique rugae are present on the merus of the second pereopod in our new species, and these are lacking in P. tortugae .

Recognition of P. karenae n. sp. casts uncertainty on identifications of P. tortugae made by previous authors. In most cases, no evidence is provided that we can use to definitively distinguish between P. karenae n. sp. and P. tortugae s.s. In previous studies, Provenzano (1959) and McLaughlin & Provenzano (1974) are often given as the primary references for determining the identification of P. tortugae specimens. While both of these works note variability in coloration of P. tortugae sensu lato (s.l.), the color of subsequently reported specimens is rarely given further mention. Numerous checklists, observational accounts, ecological studies, and taxonomic keys do not address details of coloration or morphology among the specimens they designate as P. tortugae s.l. (Schmitt 1935; Wass 1955; Provenzano 1961; Soto 1980; Abele & Kim 1986; Holmquist 1989; Martinez-Iglesias & Gomez 1989; Mantelatto & Sousa 2000; Majon-Cabezas et al. 2002; Mantelatto & Garcia 2002a, 2002b, 2002c; Raz-Guzman et al. 2004; Rahayu 2005; Tagliafico et al. 2005; Barros-Alves et al. 2015; Lemaitre & Tavares 2015; Lima & Santana 2017; Poupin 2018). Thus, our herein reported synonymies applicable to P. karenae n. sp. is limited.

Figures

FIGURE 5. Color patterns of A, Paguristes tortugae s.s., male, sl 7.2 mm (ULLZ 4783/USNM 1540547), Florida Keys, Gulf of Mexico; B, P. karenae n. sp., paratype male, sl 4.9 (ULLZ 8578/USNM 1543769), Gulf of Mexico. A, habitus, dorsal surface; B, habitus, dorsal surface.

FIGURE 6. Paguristes karenae n. sp. A, C–I, paratype male, sl 4.9 mm (ULLZ 8578/USNM 1543769), Gulf of Mexico; B, P. tortugae s.s., female, sl 4.1 mm (ULLZ 11148/USNM 1545610), Belize, northwestern Caribbean. A, carapace shield and head appendages, dorsal surface, setae omitted; B, carapace shield anterior margin showing rostrum; C, right maxilla, internal surface; D, right first maxilliped, external surface; E, right maxillule, external surface; F, right mandible, internal surface; G, right third maxilliped, external surface; H, right second maxilliped, external surface; I, right third maxilliped, internal surface. Scale bars = 1.0 mm (A–I).

FIGURE 7. Paguristes karenae n. sp., A–F, paratype, male, sl 4.9 mm (ULLZ 8578/USNM 1543769), Gulf of Mexico.A, right cheliped, dorsal surface; B, right cheliped, ventral surface; C, right cheliped, lateral surface; D, right cheliped, mesial surface; E, right second pereopod, lateral surface; F, right second pereopod, mesial surface. Scale bar = 1.0 mm (A–F).

FIGURE 8. A–I, Paguristes karenae n. sp., paratype, male, sl 4.9 mm (ULLZ 8578/USNM 1543769), Gulf of Mexico.A, right third pereopod, mesial surface; B, right third pereopod, lateral surface; C, right third pereopod dactyl, mesial surface, setae omitted; D, right fourth pereopod, lateral surface; E, fourth pereopod dactyl; F, right fifth pereopod, lateral surface; G, gonopod, mesial surface; H, gonopod, internal surface; I, telson and uropods, dorsal surface. Scale bars = 1.0 mm (A–I).