Lepidophthalmus panamensis, Felder, Darryl L. & Robles, Rafael, 2015

Felder, Darryl L. & Robles, Rafael, 2015, Two new species of the genus Lepidophthalmus (Decapoda, Axiidea, Callianassidae) from coastal Pacific waters of Central America, Zootaxa 4020 (3), pp. 431-452 : 442-450

Lepidophthalmus panamensis sp. nov.

Figures 5 a–h, 6 a–j, 7 a–k, 8 a–c

Lepidophthalmus bocourti — Biffar 1972: 65 –66, 70–72 [part, only records from Panama Canal Zone, Fort Amador Causeway]; Lemaitre & Ramos 1992:349, fig. 4.

Lepidophthalmus nr. bocourti —Staton et al. 2000: 157, 167; tables 1, 3; figs. 1–4.

Type material. Panama (Pacific coastline). Holotype: male, cl 10.2 mm ( USNM 1275011), = ULLZ 5616-A tissue/sequence voucher, photographic voucher, Panama City, Isla Naos Marina (08°54.88'N, 79°31.80'W), intertidal clayey sand swash zone of small beach between waterfront buildings, 24 April 2004, D. L. Felder. Paratypes: 1 female, cl 9.6 mm ( USNM 1275012), = ULLZ 5616-B tissue/sequence voucher, photographic voucher, collected with the holotype, 24 April 2004, D. L. Felder; 1 male, cl 9.2 mm, 6 females, cl 7.1, 7.1, 9.6, 9.6, 9.7, 10.3 mm, genetic vouchers ( ULLZ 5756), Panama City, Isla Naos Marina (08°54.89'N, 79°31.75'W), intertidal clayey sand swash zone of between breakwater rocks, 13 August 2004, D. L. Felder.

Additional material. Panama (Pacific coastline): 3 males, 7 females, 2 ovigerous ( ULLZ 4822), fragments of 8 males, 18 females, allozyme vouchers ( ULLZ 4821), Panama City, Amador Causeway, Panama Bay side (08°56.27'N, 79°32.67'W), intertidal burrows in clay with sand and coarse gravel (salinity 26 psu), between and under small breakwater rocks shoring side of causeway (now covered by construction landfill), 10 September 1990, D. L. Felder, J. H. Christy, and U. Schober. 4 males, 5 females ( ULLZ 5758), Panama City, Isla Naos Marina (08°54.88'N, 79°31.80'W), intertidal muddy sand swash zone of small beach between waterfront buildings, 24 April 2004, D. L. Felder. Colombia (Pacific coastline): 1 female ( USNM 1275013), Isla Gorgona (approximately 02°57.9'N, 78°10.3'W), sediment near old pier, 19 February 1992, J. H. Madrid. 1 juvenile male ( USNM 251736) Isla Gorgona, sediment in intertidal crevices of basaltic rocks, 0 1 July 1987, R. Franke. 1 female ( USNM 251735), Isla Cuichiche, Bahia Malaga (approximately 03°59'N, 77°15'W), intertidal mud near freshwater stream, 24 November 1985, G. E. Ramos.

Diagnosis. Rostrum acute, narrow, inclined dorsally as variably elevated to weakly arched spine, flanked by rounded shoulders slightly advanced to anterior, centered well lateral to eyestalks, creating underlying concavity overlying antennal peduncles. Flattened mesial margins of eyestalks closely opposed, tips acute. Inferior margin of major cheliped merus forming distinct single keel, weakly bicarinate in denticulate distal half, proximal hook terminally acute, subterminal process a rounded lobe or short blunt tooth, superior margin with distinct proximal notch. Propodus of male major chela with inferior margin terminating distally in acute tooth, corner forming origin of rounded-edge carina extending short distance vertically as subdistal margin of article. Dactyl of male major chela prehensile margin with heavy subquadrate tooth in proximal half, separated by broad deep notch from shouldered series of usually 4–6 subtriangularly rounded or truncate distal teeth, largest proximal; superior margin proximally with low rounded longitudinal carina. First pleonal tergite with dorsal sclerite bell-shaped, subtruncate posteriorly. Second pleomere ventrally leathery, lacking sclerotized median plate. Male first pleopod (gonopod) terminal article slightly compressed, bifurcate, subdistal tooth short, angular, distal broadly arching, terminally narrowed to small cornified tip. Appendix of male second pleopod reaching to or exceeding terminus of endopod, directed obliquely to axis of endopod, bearing terminal long setae reaching well beyond distal end of endopod. Second through fifth pleopods lacking acute distolateral spine on anterior face of basis. Telson posterior margin distinctly trilobate. Uropodal endopod narrow, elongate subtrapezoidal, broadest near or proximal to midlength, length more than twice breadth. GenBank accession numbers for 16S and 12S mt sequences of type materials as reported by Robles & Felder (2015: table 2).

Description. Frontal margin of carapace with acute, narrow rostral spine (spine missing and front rounded in 4 paratypes) flanked laterally by anteriorly advanced rounded shoulders centered lateral to eyestalks and separated from rostrum by oblique shallow posterolaterally directed furrow defining ( Fig. 5 a, b) elevated orbital margin; orbital margin and shoulders forming concavity overlying antennal peduncles; rostrum variably inclined dorsally, terminal spine forming elevated weak arch (sometimes straight) above eyestalks (in most mature specimens) extending 2/3 to 3/5 length of eyestalks in dorsal view ( Fig. 5 b), spine bearing ventral tuft of setae centered near midlength, extending above and between proximal half of eyestalks. Carapace postrostrally with 2 pairs of small setose punctae on each side of midline; dorsal oval well-defined, anteriorly intersecting shallow oblique furrow extending posterolaterally from behind eyestalks, single pair of widely separated setal punctae bearing 1 or 2 setae each near midlength, length of oval about 6/10 of postorbital carapace length; marginal suture of oval diminished at postrostral midline, stronger at posterior end with sclerotized articulation to bulbous cardiac region at posterior midline.

Eyestalks subtriangular in dorsal view, reaching at least 3/4 length of basal antennular article ( Fig. 5 a); lateral margins broadly arched, distal margins weakly sinuous to nearly straight, converging to acute apices; dorsomesial margin thickened to form a slightly swollen boss in distal 1/3, ( Fig. 5 b); distinctly faceted well-defined cornea centered on dorsal surface.

Antennular peduncle much longer and heavier than antennal peduncle ( Fig. 5 a); basal article dorsally invaginated to form statocyst occluded by setae, mostly overlain dorsally by eyestalk; second article subequal to length of basal article, third article at least 3 times length of second; second and third articles with dense ventromesial and ventrolateral rows of long, distoventrally directed setae. Antennular flagellum ventral ramus longer than third article of peduncle, with denser setation than dorsal ramus; dorsal ramus shorter than third article of peduncle, heavier than ventral ramus in swollen distal 1/3 where subterminal articles broader than those of ventral ramus, there fringed with short, dense ventral setae.

Antennal peduncle reaching about to midlength of antennular peduncle third article; basal article dorsolateral carina arched to form strong lip above excretory pore; second article with distal field of long setae on lateral boss; fourth article slightly shorter than combined lengths of first 2, slightly shorter than fifth, ventrolaterally with three small tufts of very long setae; fifth article narrower than others, long setae limited to single, small, distal, dorsolateral tuft. Antennal flagellum with sparse short setae, about 3 times length of antennular flagella.

Mandibular palp ( Fig. 5 c) large, setose, 3-segmented, third article elongate, subrectangular, truncate to weakly concave terminally; gnathal lobe of mandible subquadrate, distolateral shoulder angular, incisor process with welldefined subacutely triangular, heavily cornified, fingernail-like teeth on cutting margin (6 major subequal, plus 3 interstitial smaller ones in holotype), concave internal face with strong lip giving rise to molar process bearing strong corneous tooth proximal and internal to incisor teeth; thin, rounded paragnath positioned against proximal convex face of molar process. First maxilla ( Fig. 5 d) endopodal palp narrow, distal margin heavily setose, grading to short setae on external face, terminal article deflected at poorly defined articulation, beyond which is small weakly defined apical lobe; proximal endite with closely spaced setae lining sinuous mesial margin, becoming spiniform distally; distal endite elongate, terminally broadened and densely setose, several rows strongly spiniform; exopodite low, rounded. Second maxilla ( Fig. 5 e) margins setose, endopod constricted to narrow, curved, subacute terminus, first and second endites each longitudinally subdivided, exopod forming large, broad scaphognathite. First maxilliped ( Fig. 5 f) margins setose, rudimentary endopod overlain by distal endite; blunt terminus of proximal endite coarsely setose; distal endite ovoid, narrowed distally, proximal 2/3 of external face with setose elevation; exopod incompletely divided by obliquely curved suture on external face, internal face with transverse suture sinuous, complete, sinuous, full distance to lateral incision; margin lined by long setae, broadly arched proximal and distal to incision, mesial margin with comb of close-set very long setae, external face with dense field of mesially deflected setae distal to oblique suture; epipod large, broad, anterior end strongly tapered. Second maxilliped ( Fig. 5 g) rami with margins heavily setose, endopodal merus and propodus arched, flexor margin of merus with comb of long setae, internal face produced distally to form rounded marginally setose lobe extending over internal proximal margin of short carpus; merus length about 4 times width; propodus length exceeding 2/3 length of merus, longest setae originating on extensor margin and distal half of external face; dactylus slightly swollen, twice as long as broad, rounded terminally, distal half bearing short stiff cornified setae; exopod broad, bladelike, narrowing distally, distinctly overreaching endopodal merus, arcuate, terminally rounded; bilobed epipod with short rounded basal lobe, elongate narrowly tapered, distal lobe. Third maxilliped ( Fig. 5 h) with small, terminally subacute, rudimentary exopod; endopod large, setose; endopodal ischium subrectangular, maximum diagonal length slightly less than 2 times width at midlength, internal face with very weakly defined rudiment of obliquely oriented longitudinal carina on proximal half; merus short, subrhomboidal, broader than long, mesial margin distinctly arcuate; carpus subovoid, longer than broad, internal face with densest field of stiff setae in distal third; propodus large, subovoid to subrhomboidal, no longer than broad, internally with dense tufts of stiff setae centered on proximal half, lacking setose angular lobe on flexor margin immediately below articulation of dactylus, demarcated at most by weak carina scarely divergent from flexor margin short distance onto external face; dactylus narrow, strongly arcuate proximally, long setae of extensor and distal margins including stiff bristles at terminus.

Branchial formula as reported for congeners (Felder & Staton 2000); endopods and epipods as previously described ( Felder & Rodrigues 1993), branchiae limited to single rudimentary arthrobranch on second maxilliped, pair of arthrobranchs on third maxilliped, and pair of arthrobranchs on each of the first through fourth pereopods.

Major cheliped located on either right or left side, shape and ornamentation sexually dimorphic. Major cheliped of male ( Fig. 6 a, b; Fig. 8 a, b) massive, fingers heavily armed; ischium slender, superior margin sinuous, inferior (flexor) marginal carina armed by very small denticles on proximal 1/2 to 2/3, usually becoming more widely separated distally, ending in few enlarged and often compound denticles on distal elbow; merus with distinct depression or notch in proximal 1/4 of superior margin, inferior (flexor) strong marginal keel arcuate distally, single over most of length, evidence of weak parallel carina to external side in distal half, terminally bifurcate proximal hook at outer base of keel, hook terminating in spiniform or dentiform inferodistally directed tip usually paired with weak subterminal lobe, 3–6 small blunt denticles originating from keel margin; carpus broad, subquadrate, superior and inferior margins keeled, near parallel in distal half, terminated distally in subacutely angular corners, inferodistal corner forming origin of short roundly edged carina extending short distance vertically onto outer face of article; propodus broad, heavy, length of fixed finger about 1/2 length of palm; inner face of palm proximally smooth, lacking distinct rounded swollen boss centered near midline, distally with carina extending proximally from inner prehensile margin of fixed finger proximal to gape of fingers and above weak elongate roughened concavity extending almost full length of article; outer face with carina defining weak depression extending proximally from gape of fingers, depression roughened by field of low turbercles extending onto fixed finger; keel of superior propodal margin distinct in proximal half of palm, obsolete distally, keel of inferior margin distinct full length of palm, becoming obsolete on fixed finger where broken by large setose punctae; fixed finger originating below somewhat rounded short tooth at proximal end of gape, prehensile margin weakly armed by low tooth originating from outer prehensile margin, centered near 2/5 to ½ length of fixed finger; fixed finger with well-defined separation of inner and armed, elevated outer prehensile margins, inner margin unarmed but forming thick rounded carina extending onto palm; dactylus with hooked tip, superior margin with (at most) low unarmed rounded carina, lacking distinct elevation of short proximal carina or tubercle, internal face with weakly defined carina forming unarmed prehensile margin, outer face swollen above outer prehensile margin bearing (usually) 2 heavy, prehensile teeth, proximal tooth heavy, subtruncate, weakly subquadrate (sometimes roughened by microtubercles) centered near 1/3 length of finger, separated by subquadrate U-shaped notch from complex elongate bladelike distal tooth originating near midlength of dactyl and extending almost to terminal hook, elevated basal prominence of distal tooth thickest (sometimes a compound denticle), distally sloping prehensile edge armed by series of shouldered subacute denticles, truncate cutting edges usually microtuberculate.

Major cheliped of female ( Fig. 6 c; Fig. 8 c) less massive, less strongly armed and sculpted than in male, dactylus narrower, less massive than fixed finger proximally, fingers forming asymmetric pincer; dactylus prehensile margin sinuous, evenly armed by serration of low rounded small denticles; fixed finger basally broader than in males, notch at base of fixed finger a narrow U-shaped incision proximal to enlarged denticle at proximal end of serration of smaller denticles on most of prehensile margin, deeply concave between inner and outer prehensile margins; superior and inferior margins of propodus convergent distally, article more compressed ventrally than dorsally; tip of dactylus overreaching tip of fixed finger when tips crossed, fully flexed fingers incompletely filling incisional notch at base of fixed finger.

Minor cheliped of male ( Fig. 6 d) sparsely armed; ischium weakly serrate by small denticles on most of flexor margin, denticles more widely separated into microtubercles distally; merus mostly unarmed, inferior margin with at most 1 weak tubercle or swelling proximally; carpus with acute distal comers, very weak rounded carina extending vertically from inferior corner; fixed finger nearly as heavy as dactyl, less hooked distally, prehensile margin lacking teeth, sloping proximal 2/5 with broad field of dense elongate setae filling about half of gape length, extending somewhat onto internal face; dactylus prehensile margin with transversely paired rounded basal tooth above setae filling gape, weak evidence of subterminal tooth as broad swelling, hook terminated in subacute cornified tip. Minor cheliped of female with proximal notch in prehensile surface distal to which is low transversely bilobate tooth proximal to dense tufts of setation on most of prehensile surface ( Fig. 6 e) with dense, elongate prehensile setation of fixed finger much less developed than in males.

Second pereopod ( Fig. 6 f) chelate, flexor margins of merus and carpus lined with evenly spaced long setae, inferior margin of propodus with long setae proximally, grading distally to dense field of short, hooked bristles; middle 1/3 of fixed finger with patch of short stiff bristles just outside prehensile margin; superior margin of dactylus with proximal long setae grading to short stiff hooked bristles distally. Third pereopod ( Fig. 6 g) merus length less than 2.4 times width; propodus with inferodistal margin very weakly trilobate, small middle low, formed by weakly undulate margin between major distal and proximal lobes, setal tufts giving margin weakly scalloped appearance, lobes demarcated by furrows on internal face, distal margins of lobes with dense fringe of tufted setae concealing shorter corneous bristles, middle margin of distal lobe with heavier, weakly hooked, distally directed corneous tooth arising from margin, concealed by longer setae, proximal lobe bearing longest setae of article on inferior margin, patterned tufts of lighter setae densely covering upper and lower fields on external face of article; dactylus tear-shaped, superior margin concealed by long dense setae on outer face, margin internally sinuous, article terminating in short, narrow, ventrolaterally directed corneous tooth, outer face with fields of setae and shorter stiff bristles lining inferior margin, grading to fields and poorly defined rows of much finer setae above; mature female gonopore at least 4/10 coxa length ( Fig. 6 h). Fourth pereopod ( Fig. 6 i) weakly subchelate, inferodistal process of propodus (= fixed finger) angular, tip terminally rounded, extending distally no more than 1/ 3 length of dactylus, immediate inferior margin of tip with heavy, hooked, subterminal corneous spine, inferior margin proximally with additional much lighter, longer, short bristles, tip and spine obscured by dense brush of setae originating from inferior margin and lower external face, separated dense field covering upper external face and partially concealing dactylus; dactylus elongate, tear-shape, superior margin arched, prehensile margin densely covered with short hooked bristles, article terminating in short ventrolaterally directed corneous tooth. Fifth pereopod ( Fig. 6 j) chelate, fingers spooned, terminally rounded, with corneous pectinate margins; propodus with dense field of long, close-set setae on internal face, fixed finger slightly deflected; dactylus terminally narrower than fixed finger, hooked form and flexure into larger spoon of fixed finger obscured by dense setation on distal 2/ 3 of propodus and superior surfaces of dactylus.

Pleomeres mostly smooth dorsally ( Fig. 8 a–c). First pleonal tergite with translucent, bell-shaped or fingernailshaped middorsal sclerite separated anteriorly by membrane from thickened, narrow transverse anterior sclerite connected laterally to narrow thickened anterolateral sclerites, dorsal sclerite truncate to weakly rounded posteriorly, no evidence of isolated small sclerites in ill-defined posterolateral membranes to each side. Second tergite rounded posterolateral lobe below suture sclerotized at least as heavily as remainder of tergite, lobe bearing distinct tuft of fine long setae near posteroventral margin; ventrolateral prominence of tergite centered slightly anterior to midlength of tergite. Third to fifth tergites each laterally encompassing finely pubescent, membranous subcircular or suboval area below weak posterolateral suture and fringe of long setae, membraneous areas of third and fourth tergite more posteriorly positioned than on fifth, that of fifth tergite slightly smaller, more circular. Sixth tergite with 2 transverse posterolateral lines of short setae anterior to posterolateral groove from which transverse and posterior sutures originate; ventral edge of tergite posterolateral margin marked by 2 or 3 closely parallel longitudinal lines of micropunctae bearing very fine setae; transverse suture obsolete across most of sixth tergite ( Fig. 7 k), laterally connecting to short longitudinal posterior suture, or very nearly so; tufts of stiff setae mesial to each posterior suture, on posterolateral corners, and as 4 short lines or tufts of stiff setae on posterior margin, lateral pair longest.

Ventral surfaces of pleomeres lacking general cover or extensive armor of sclerotized plates and tubercles; in male, heaviest sclerites of first pleomere conspicuous ( Fig. 7 a), forming narrow convergent furrows or channels extending anteromesially from base of each pleopod, plates convergent, touching anteriorly, furrows roughly accommodating first pleopods when fully flexed against pleon; in female, sclerites shorter, furrow narrower, converging anteriorly and articulating or fusing to from truncate median terminus; second pleomere in both sexes ventrally lacking evidence of longitudinally furrowed or flattened median plate and of thickened small sclerites forming tubercles embedded in ventral pleonal membranes.

First pleopod of male and female uniramous, composed of 2 articles; in male, originating from atop outer of 2 sclerotized ridges forming narrow sinuous trough or channel roughly conforming to flexed pleopod ( Fig. 7 a); appendage length less than 1/2 that of second pleopod, proximal article about 2 times length of terminal article ( Fig. 7 b, c), terminal article weakly compressed, weakly concave anterior edge narrow, convex subterminal margin less so and bearing long setae, article bifurcate forming 2 blades, subdistal angular, short (weakest in large individuals), lightly cornified tip, distal blade much the stronger, bearing acute cornified tip; in female ( Fig. 7 , d), extended length slightly less than that of second pleopod, proximal article bearing low setose swelling near midlength, slightly shorter than terminal article, terminal article forming narrow compressed blade beyond setose lobe at midlength. Second pleopod of male and female biramous, with appendix on endopod; in male ( Fig. 7 e–g), typical mature appendix (representing obscure merging of appendix interna and appendix masculina) large (dimunitive on one side in illustrated paratype), oriented obliquely to axis of endopod, scarely distinguishable patch of obsolescent hooks (= cincinnuli, vestige of appendix interna) roughening mesial margin (not evident in all), length subequal to or exceeding triangular tip of endopod, longest terminal setae exceeding appendix length, overreaching both endopod and exopod, both rami bearing sparse short setae; in female ( Fig. 7 h, i), basis with broad lobe on mesial side, appendix interna small, narrow, markedly overreached by narrow terminus of endopod, terminally subacute, terminus and mesial subterminal shoulder with field of minute, rudimentary hooked setae, both rami bearing long setae. Second through fifth pleopods with, at most, a low tubercle or tooth on anterior face of basis at condylar articulation with exopod. Third to fifth pleopod pairs forming large, posteriorly cupped fans when crosslinked by hooked setae of stubby appendices internae embedded in opposed margins of triangular endopods ( Fig. 7 j).

Telson ( Fig. 7 k) broad, subrectangular, width about 1.4 times length, lateral margins weakly sinuous, broadest near midlength, posterior margin distinctly trilobate, median lobe much broader than pronounced lateral lobes; dorsally with 3 pairs of strong setal tufts, posteriormost pair nearest midline in posterior half of telson, 2 anterior pairs roughly aligned longitudinally well lateral of midline, posteriormost near midlength, lateral margins with pair of strong setal tufts just posterior to midlength, posterior margin well-developed tufts on 2 lateral lobes. Uropod ( Fig. 7 k) with flattened, triangular to lobiform posterodorsally directed flange-like tooth on protopod, narrower more acute tooth on proximal article of exopod, both positioned to abut or overreach anterior margin of extended endopod; endopod elongate, subtrapezoidal, at least twice as long as broad, posteromesial margin with broken fringe of long setae, tapering to rounded angle of terminus bearing marginal fringe of long setae, distal end reaching to or almost to distal end of anterodorsal plate on flexed exopod; exopod anterodorsal plate falling well short of distal margin, posterodistal edge of plate with series of heavy spiniform setae grading to finer, dense, elongate setae of distal plate margin; distal margin of exopod with dense fringe of setation, longest posteriorly.

Color. In life, color in this species varies to some degree, even among mature individuals, but pigmented areas of the body tend to include primarily carmine red to reddish orange chromatophores patterned over translucent yellow backgrounds. Reddish orange colors are particularly apparent immediately posterior to the rostrum and frontal margin shoulders, near the middle of the dorsal oval, along the posterodorsal margins of the pleomeres, and broadly along the exposed margins of the telson. The more heavily sclerotized integument of the pereopods can be whitish with little evidence of pigment, though the chelipeds of fully mature specimens commonly have a blush of rose red to carmine over white, especially along the superior surfaces. The pleopods and uropods are commonly yellowish to olive green. These colors, based on collections from Panama, are in close agreement with coloration reported for Colombian specimens by Lemaitre & Ramos (1992), albeit at the time under the name L. bocourti .

Size. Maximum observed postorbital carapace length of male 10.5 mm; of female 11.9 mm. Maximum embryonated egg length on preserved ovigerous females about 1.4 mm for immature clutches and 1.6–1.7 mm for immediate pre-hatch.

Habitat. These obligate burrowers were found in 1990 by relocating a collection site on the Panama Bay side of the Fort Amador Causeway reported in the dissertation of Biffar (1972). That report described the site as moderately coarse sand occurring near the high tide line, where animals occurred in densities exceeding 140 per square meter in fragile burrows extending to about 0.5 m deep in sediments. The precise site was located but erosion control along the causeway had markedly changed the setting. Specimens were eventually found on a steep beach there, but only after turning over exposed intertidal stones, beneath which these animals had constructed channel-like burrows connected to deeper tunnels into a narrow band of clay along the shoreline (several meters wide) dominating sediments of the middle intertidal. None of these animals were burrowed deeper than 0.5 m, and the sediments in which they had constructed burrows were comprised heavily of sandy clay mixed with coarse gravel. However, fully mature animals, including ovigerous females occupied these burrows, and densities exceeding 100 per square meter were estimated. The normally applied yabby pump was of limited use in this setting, requiring excavation by shovel. This site was completely covered by construction landfill on return to it in 2004, but a search for additional specimens in the vicinity produced them on two occasions in yabby pump extractions from sparse populations on a clayey sand beach adjacent to the Naos Marina. Collections there were adjacent to and among large breakwater rocks, and subsurface layers of clay were evident in the sediments extracted. Neither site represents an unaltered natural setting, and both are subject to periodic salinity decreases, though they do not experience the extreme polyhaline conditions of upper estuaries.

It cannot be stated for certain if other specimens from the Panama Canal Zone taken by a dredge maintaining the canal channel, also reported by Biffar (1972), might also represent L. panamensis sp. nov. If so, it would indicate their ranging into deeper subtidal waters. Specific data are lacking for the single 1992 collection from Isla Gorgona, Colombia, though it can be deduced from the site alone that this is a comparatively high salinity habitat. However, original collection data for the very immature male collected there in 1987 indicated that it came from sediments in intertidal crevices of basaltic rocks. By contrast, the specimen from Bahia Malaga, Colombia, appears to have come from muddy sediments near the mouth of a freshwater stream (Lematire & Ramos 1992), suggesting adaptation to a broad range of salinity.

Distribution. Eastern Pacific: Island off southwestern Colombia and western Colombian estuarine embayments to Panama Bay and vicinity (intertidal waters along beaches and shoreline banks and tidal stream mouths of embayments).

Type locality. Pacific coast of Panama, Panama City, Isla Naos Marina (08°54.88'N, 79°31.80'W).

Etymology. This species is named for its type locality.

Remarks. The smaller size of materials here assigned to L. panamensis sp. nov. initially led Biffar (1972:70– 71) to solicit the opinion of M. de Saint Laurent as to whether these materials were conspecific with the type of L. bocourti in collections of the Paris museum. While differences were found, these were concluded to likely represent size or ontogenetic variations, and indeed, the characters mentioned would not have been useful to separate the species. However, the presence or form of pleonal plating (Felder 2003) was not at the time a known character, while diversity and potential for regional endemism in this genus was also likely underappreciated. As for L. rafai and L. natesi sp. nov., L. panamensis sp. nov. can be readily separated from both L. bocourti and L. eiseni by the lack of median ventral plating on the second pleomere, in addition to the general limitation of ventral sclerotization. It can in turn be separated from L. rafai by both its distinctly trilobate posterior telson margin and its elongate subtrapezoidal uropodal endopods, features that it shares with L. natesi sp. nov. In L. rafai , the telson lacks the strong posterior lobes and the uropodal endopods are much more broadly ovoid. Finally, L. panamensis sp. nov. differs from L. natesi sp. nov. in body size, relative mature female gonopore size, and egg size, and can be distinguished by a number of morphological features despite their similarities in the posterior margin of the telson, uropodal endopod, flange-like tooth of the uropodal protopod, and some other characters. In L. panamensis sp. nov. the rounded shoulders of the carapace frontal margin, centered immediately to each side of the eyes, project more strongly to the anterior and are more distinctly separated from the rostrum by an oblique posterolaterally directed furrow or depression. This gives the shoulders a more arched appearance, forming hoods over the antennal peduncles. Furthermore, the dorsal sclerite of the first pleomere is distinctly different, being bell-shaped and lacking a distinctly broadened membranous area to each side. Major differences are also found in dentition and shape of the major cheliped, though these can be somewhat similar in immature specimens. In mature specimens, the merus of L. panamensis sp. nov. has a clearly developed proximal notch in the superior margin and a much simpler proximal hook on the inferior margin than does L. natesi sp. nov. Also, the prehensile tooth of the fixed finger is much weaker than in L. natesi sp. nov. In both sexes, relative lengths of the minor cheliped fingers differ between the species, those of L. panamensis sp. nov. being relatively shorter compared to propodus height than in L. natesi sp. nov. Specifically for females, the dentition of the fingers in both the major and the minor chela differs between the species, with the major fixed finger having an enlarged denticle immediately distal to the proximal incision and the minor dactyl having a low but distinct proximal tooth on the prehensile margin, neither of which is seen in L. natesi sp. nov.

Characters of the male pleopods could also be cited to support the separation, both first and second, with the oblique orientation of the appendix on the male second being apparently unique to L. panamensis sp. nov. However, in comparative study of the type series for this species, it became apparent that these appendages do vary considerably with maturation and by occurrence of occasional anomalies, especially in the appendix of the male second pleopod ( Fig. 7 e–g). Thus, comparative interpretations based on this structure must be made with caution.

Were a single specimen of some large series found to lack the rostrum spine, little should be made of it, but the present type series includes no less than 4 individuals in which the middle of the carapace front is represented as nothing more than a broadly rounded lobe, lacking all evidence of the rostral spine. In all other respects, these animals appear typical of the species. Whether this is some occasionally expressed labile morphological feature or a developmental malformation due to environmental effects is presently unknown, but worthy of further study.

As noted in the synonymy above, the present description applies to materials cited in Staton et al. (2000) as “ Lepidophthalmus nr. bocourti ” and “ L. nr. bocourti ”, or referred to under the abbreviation “LBPA”. Allozyme analyses in that paper were based on tissue from ULLZ 4821 collected from the Fort Amador Causeway, and fragmentary voucher materials are conclusively identifiable as Lepiophthalmus panamensis sp. nov. Being one of two undescribed eastern Pacific species alluded to by Staton et al. (2000: 167) as having ventral sclerites “shared to varied degrees” with other ventrally plated species, correction of that misleading statement is required. Neither the population of “ L. nr. bocourti ” referred to there (here described as L. panamensis sp. nov.), nor the “one additional undescribed species” (here described as L. natesi sp. nov.), have a median ventral sclerotized plate on the second pleomere. There may nonetheless be small paired anterior plates to each side or lateral plates immediately anterior to the pleopods ( Fig. 4 b), but the median region is at most leathery, lacking a major centrally located sclerite and adjacent small sclerites embedded in the membrane. At most in both L. panamensis sp. nov. and L. natesi sp. nov., the leathery ventral membranes of the pleomeres in some specimens appear under high magnification to be rather uniformly peppered by very tiny whitish particles embedded in the integument. It is unknown whether or not these represent a homolog of the much larger sclerites and plates expressed in related species.

In the course of reviewing abbreviated larval development that appears to characterize most species of Lepidophthalmus, Nates et al. (1997: 512) note that some of the most extreme abbreviation may occur in one of the undescribed “Pacific congeners”, a comment that in fact applied to the species herewith named L. panamensis sp. nov. Remarkably, ovigerous females collected from Panama 10 September 1990 carried large eggs until 23–24 November, while held in the lab at 26 psu in a 12:12 light:dark photoperiod. Enlarged eyespots were observed on 16 November but hatching of all 28 remaining eggs was not detected until decapodid stages (first postlarval = megalopa) were observed in the culture bowl within a maximum of 2 days after hatch. Initially docile on the bottom of the bowl, they became very active swimmers and feeders within hours, especially when exposed to light. Despite a careful search, no evidence of molted exuvia from a preceding zoeal stage was found in the culture bowl, suggesting the possibility of direct development or perhaps one that involved a brief prezoea with thin integument too fragile to remain intact. As noted by Nates et al. (1997), the question remains as to whether larvae in some members of this genus might undergo benthic development within the burrows of females, and at least potential for such adaptation is found in L. panamensis .

Finally, our inclusion of the specimens from Isla Gorgona and Bahia Malaga, Colombia, in L. panamensis sp. nov. is undertaken with some reservation. Two of these were previously treated as L. bocourti by Lemaitre & Ramos (1992), and all three specimens were kindly made available for study by R. Lemaitre. The only male among these three, from Isla Gorgona, is extremely immature and fragmentary, making its definitive identification very tentative. The two females, one from Isla Gorgona and the other from Bahia Malaga, both fit L. panamensis sp. nov. in terms of those features that are intact in the chelipeds (including as illustrated by Lemaitre & Ramos 1992: fig. 4), size of the mature female gonopore, pleonal sclerite development, telson shape, and configuration of the uropodal endopod (this latter feature varying from the cited illustration). However, the tooth of the uropodal protopod is somewhat atypical on both sides in both specimens in forming lateral lobes rather than broadly triangular teeth that overreach the margin of the extended exopod. Until additional materials can be secured from these habitats, preferably of gene sequence quality and including mature males, we provisionally assign these populations to L. panamensis sp. nov.

Figures

FIGURE 4. Color patterns and habitus of Lepidophthalmus natesi sp. nov.: a, f, female paratype, lateral habitus (a) and dorsal sclerite of first pleomere (b, contrast enhanced), cl 12.7 mm, Estero de Las Peñitas, Pacific coast of Nicaragua (ULLZ 4509); b, e, male paratype, ventral with second pleopods removed (b), and external face of cheliped (e), cl 15.5 mm, Estero de Las Peñitas, Pacific coast of Nicaragua (ULLZ 4509); c, d, male paratype, lateral habitus (c) and dorsal habitus (d), cl 16.6 mm, Estero Ciego, Pacific coast of Nicaragua (ULLZ 10838).

FIGURE 5. Lepidophthalmus panamensis sp. nov., holotype male, cl 10.2 mm, Panama City, Isla Naos Marina, Pacific coast of Panama (USNM 1275011): a, anterior carapace, dorsal; b, rostrum, eyes, and frontal margin, right; c, right mandible, paragnath detached, external; d, right first maxilla, without setae, external; e, right second maxilla, without setae, external; f, right first maxilliped, without setae, external; g, right second maxilliped, external; h, right third maxilliped, external. Scale bars = 5.0 mm (a), 2.0 mm (b, d – f), 1.5 mm (c, g, h).

FIGURE 6. Lepidophthalmus panamensis sp. nov.; a, b, d, f, g, i, holotype male, cl 10.2 mm, Panama City, Isla Naos Marina, Pacific coast of Panama (USNM 1275011); c, e, h paratype female, cl 9.6 mm, same locality (USNM 1275012); j, paratype male, cl 9.2 mm, same locality (ULLZ 5756): a, major (left) male cheliped, external; b, major (left) male cheliped, internal; c, major (right) female cheliped, external; d, minor (right) male cheliped, external; e, minor (left) female cheliped, internal; f, right second pereopod, external; g, right third pereopod, external; h, right third pereopod coxae and gonopores, ventral; i, right fourth pereopod, external; j, right fifth pereopod, antero-internal. Scale bars = 5.0 mm (a – e, h), 3.0 mm (f, g, i, j).

FIGURE 7. Lepidophthalmus panamensis sp. nov.; a, b, e, j, k, holotype male, cl 10.2 mm, Panama City, Isla Naos Marina, Pacific coast of Panama (USNM 1275011); c, f, g, paratype male, cl 9.2 mm, same locality (ULLZ 5756); d, h, i, paratype female, cl 9.6 mm, same locality (USNM 1275012): a, first pleomere of male, right pleopod removed, ventral; b, right male first pleopod, lateral; c, right male first pleopod, lateral; d, right female first pleopod, lateral; e, right male second pleopod, posterior; f, right male second pleopod, posterior; g, left male second pleopod, posterior; h, right female second pleopod, posterior; i, right female second pleopod, mesial; j, endopod of right third pleopod; k, telson and uropods, dorsal. Scale bars = 3 mm (a), 1 mm (b – h), 2.0 mm (j), 4.5 mm (k).

FIGURE 8. Color patterns and habitus of Lepidophthalmus panamensis sp. nov.: a, b, male holotype, dorsal (a) and right lateral (b) habitus, cl 10.2 mm, Panama City, Isla Naos, Pacific coast of Panama (USMN 1275011); c, female paratype, dorsal habitus, cl 9.6 mm, same locality (USNM 1275012).