Lithopagurus yucatanicus Provenzano 1968

Lithopagurus yucatanicus Provenzano, 1968 (Fig. 1)

Lithopagurus yucatanicus Provenzano, 1968: 629, figs 1-4; 1971: 237.

TYPE MATERIAL. — Caribbean Sea. Pillsbury, stn P-584, 21°02’N, 86°24’W, 353- 347 m, 23.V.1967, holotype 2.8 mm (USNM 122636), paratype ovig. 2.6 mm (USNM 122637); stn P-581, 21°05’N, 86°23’W, 146-265 m, 22.V.1967, paratype 2.8 mm (MNHN-Pg 458).

TYPE LOCALITY. — Caribbean Sea, 21°05’N, 86°23’W, 146- 265 m.

DISTRIBUTION. — Arrowsmith Bank, off the Yucatan Peninsula, Mexico.

DESCRIPTION

Shield (Fig. 1A) considerably broader than long, distinctly vaulted, surface with few simple setae laterally. Rostrum prominently produced, overreaching spines of ocular acicles, broadly triangular, with short, rounded, median keel, terminating in acute small spine. Lateral projections weakly produced, but each with acute terminal spine. Ocular peduncles short, approximately 0.6 length of shield, swollen basally, concave medially; corneal diameter approximate 0.3 of peduncular length; ocular acicles quite small, triangular, each with terminal spine. Antennular peduncles overreaching distal margins of corneas by full length of ultimate peduncular segments. Antennal peduncles overreaching corneas and reaching to proximal halves of ultimate segments of antennular peduncles; second segments each with dorsolateral distal angle produced, terminating in simple spine and with few short, simple setae; antennal acicles reaching to proximal margins of ultimate peduncular segments, each with simple terminal spine and few moderately short, marginal setae.

Chelipeds grossly unequal (Fig. 1), right operculate; dactyl and fixed finger with distinct hiatus, both terminating in corneous claws. Dactyl with dorsomesial margin not delimited, dorsal and dorsomesial surfaces both with covering of moderately long, stiff setae arising from low protuberances. Dorsal surfaces of palm and fixed finger with similar setation and low protuberances, dorsomesial margin of palm with row of very small spines. Carpus with four spines in distal half of dorsomesial margin, distal margin with numerous moderately long stiff setae. Left cheliped very slender; unarmed but segments covered with moderately dense, stiff setae; carpus unarmed or with two or three spines on dorsal surface.

Ambulatory legs detached, but appear to be approximately as long as right cheliped. Dactyls of second pereopods approximately twice length of propodi, dactyls of third about 1.5 length of propodi; dorsal, lateral and mesial faces each with numerous, moderately long, stiff setae; ventral margins each with eight to 10 corneous spines. Propodi unarmed but surfaces all with scattered short to moderately long, stiff setae. Dorsal margins of carpi of second pereopods each with prominent dorsodistal spine and two smaller spines in posterior half; third pereopods with only dorsodistal spine or with one small spine on dorsal surface in addition to dorsodistal spine; with scattered short to moderately long, stiff setae. Meri each with sparse dorsal and ventral setae. Fourth pereopods semichelate, dactyls very short; propodi each with multiple rows of scales in rasp. Fifth pereopods weakly chelate. Sternite of third pereopods with reduced subquadrate anterior lobe, concealed by setae.

Pleon reduced (Fig. 1); tergites 2-5 well defin- ed, entire but membranous and provided with scattered short, stiff setae, tergite 6 well calcified, subquadrate, also with covering of moderately short, stiff setae. Female with pleopods 2-4 on left, with second somewhat smaller than others; right side sometimes with rudimentary, very weakly biramous second pleopod. Uropods very large, generally symmetrical; both rami with elongate rasps of small corneous scales. Telson roundly subrectangular, without lateral incisions or indentations; terminal margin entire, unarmed.

REMARKS

Provenzano (1968) described the carpus of the left cheliped as having two or three large spines on the dorsal surface. Only one spine is illustrated for the female paratype from station P 581, but no spine was observed when the specimen was reexamined; it possibly had been broken off. Other discrepancies between the present diagnosis and the original description reflect morphological variations between the described male holotype and the female paratypes and/or semantics.

No mention was made by Provenzano (1968) about the rudimentary right second pleopod present on the female paratype in the MNHN; no similar right second pleopod occurs in the other female paratype. Whether incomplete loss of this pleopod is an anomaly or a variable condition in this genus cannot be determined at present. Both new species are known only from their male holotypes.