Cancellus viridis Mayo 1973

Cancellus viridis

MATERIAL.—1 ♂, 4.2 mm, cl. 6.7 mm, holotype; P–134, north of Panama; 9° 14.6′-9° 13.5′N, 80°21.8–80°22.8′W; 48–49 m; in a piece of siliceous sponge; 20 July 1966; 10′ otter trawl; USNM 128732.—1 , 4.5 mm, paratype collected with holotype; USNM 128733.

DESCRIPTION OF HOLOTYPE.—Cephalothoracic shield only slightly wider than maximum shield length; frontal margin of shield with rounded postorbital indentations, bordered between antennal peduncles by continuous narrow inflated rim, slightly broader behind ocular peduncle, armed at lateral terminations with 2 minute denticles. Rostrum broad, sides slightly concave, exceeding lateral projections. Crescentic transverse depression behind frontal rim, widening behind ocular scales; swelling posterior to apex of rostrum followed by a groove extending posteriorly, separating 2 areas of irregular transverse ridges and grooves. Raised sculpturing on both anterolateral edges of shield extending mesially behind frontal rim to a point behind ocular peduncles. Shield laterally convex, smooth in center, especially smooth in gastric region.

Calcified part of cardiac region approximately as long as wide; rounded posteriorly.

Ocular scales well separated, mesial two-thirds projected anteriorly, armed with two spinules distally. Ocular peduncle approximately two-thirds length of shield, slender, slightly broader proximally. Uneven row of widely spaced tubercles with setae on dorsal surface of ocular peduncle, curved toward inside distally. Cornea slightly inflated with basal emargination dorsally.

Antennular peduncle approximately as long as ocular peduncle when extended. Basal segment with 4 spines anteroventrally.

Fifth article of antennal peduncle reaching about two-thirds length of ocular peduncle. Antennal acicles reaching to one-half length of ocular peduncle. Left antennal acicle with 2 distal spines, one slightly lateral to those, and one on the inner margin (4 spines total). Right antennal acicle with 3 distal spines, one behind those on inner margin and 2 on outer margin (6 spines total). All acicular spines projecting anteriorly.

Opercular surface of manus of cheliped tuberculate; tubercles in irregular transverse rows, appearing finer toward central longitudinal concavity. Several tubercles larger than others, but not in distinct row. Depression extending into opercular surface of carpus, bordered posteriorly by a projecting ridge divided into 3 tuberculate lobes with setae on crests; anterior margin of outer carpal lobe serrated with setae on edge. Inner face of manus smoothly reticulate; raised crest at boundary between inner and opercular faces in approximately 6 irregular lobes, determined by small fissures at base between lobes; tubercles obscure lobation. Rounded knob in raised medial area on opercular surface of manus at distal end. Inner face of dactylus with single row of 4 small protuberances with corneous denticles near dorsal ridge and 4 large tufts of setae.

Opercular surface of P2 tuberculate, carpus and propodus concave, dactylus flat. Inner dorsal ridge of carpus irregularly toothed; outer ridge divided into 4 or 5 toothed lobes. Inner ridge of propodus with 7 small groups of tubercles and one toothed distal lobe; outer ridge expanded and thin, divided into 5 or 6 overlapping toothed lobes. Inner margin of dactylus with a row of approximately ten tubercles of diminishing height, 2 or 3 of these paired; 5 corneous denticles on ventral border of dactylus, one minute denticle adjacent to dark tip; dorsal margin in approximately nine sections: 4 proximal tuberculate lobes, and 5 groups of tubercles diminishing in size to a single protuberance distally.

Dorsal surface of carpus of P3 broadening distally, with several tubercles. Dorsal surface of propodus rough with scattered groups of 2 or 3 setae; 5 or 6 prominent teeth or tubercles on margin, armed with accessory tubercles at base; group of teeth and tubercles at distal end; small corneous tooth on ventral margin of propodus at insertion of dactylus. Dorsal margin of dactylus with a small protuberance with several setae followed by 9 teeth with setae, diminishing in height distally; ventral margin with row of 6 corneous clenticles and one minute denticle adjacent to corneous tip.

P4 with oval pad of corneous granules on face of propodus, slightly longer than wide. Dactylus slender, subcylindrical, extending slightly beyond distal edge of propodus, with row of corneous denticles. No spines on carpus at insertion of propodus.

Dactylus of P5 slightly more than one-third length of propodus. Corneous pad on propodus extending onto dactylus as double row of corneous granules. Setae on distal part of P5 directed posteroventrally, not plumose, serrated on distal half.

Fifth coxal segments flattened, with very shallow central depression. Gonopores on male located anterior to depression.

Abdomen spherical; partly calcified transverse plate on anterior and posterior part; no pleopods on male.

Sixth abdominal tergite hexagonal, its length slightly less than three-fourths maximum width. In front of triangular lateral projections of transverse carina on each side, one spine projecting anterolaterally, inserted near lateral margin. Ridge on forward margin armed with groups of irregular blunted teeth, approximately 10 on each side; slight indentation in margin medially. Deep rounded depression medially, anterior to transverse carina. Rounded protuberances scattered over surface of plate. Posterior lobe with shallow longitudinal depression medially. Posterolateral borders serrate. Posterior margin inflated, armed with 3 to 5 small teeth.

Telson irregularly rounded, length approximately three-fourths width; surface with medial swelling, depressed to margins; rounded protuberances symmetrically placed, one on either side of swelling with area of pigmentation around base of seta. Median denticle on posterior margin.

Dorsal face of protopod slightly concave. Posterior projections each with 4 small teeth, more distinct on left side of type-specimen, and one spine underneath. Anterior to these, one rounded protuberance with several setae.

COLOR.—The general color of recently preserved material is green, orange, and brown markings on a cream background. There are large green areas on the central anterior one-third of the shield, on the lateral margins, and just anterior to the gastric pits. Reddish brown markings are scattered in the depressions on each side of the semi-circular sculptured areas of the shield, at the middle of the lateral margins, and around the gastric pits.

The remainder of the shield is pale orange, as are the ocular peduncles, antennal acicles and flagella, and antennules. The ocular scales are pale orange with green patches. The antennal peduncle is light orange with a darker greenish brown band around the middle.

The calcified part of the cardiac and branchial regions have scattered pigmentation.

The chelipeds and ambulatory legs have green and brownish orange markings over a pale orange or cream background. A few reddish brown spots are scattered on the surfaces; one is especially distinct on the inner surface of the dactylus at its insertion. The carpus and merus have more orange color, particularly in depressions and on dorsal margins. Green color forms a band on the distal part of the merus of P2; the proximal part has brownish orange markings. The green banding is more distinct on the proximal parts of the dactylus, propodus, and carpus of P3; the merus is green distally and on the outside, but has more orange and brown proximally and on the inner surfaces. The green color is more noticeable on the outer faces of both P2 and P3. P4 and P5 are pale with scattered orange and green markings.

The coxal segments have green marks on a pale orange background; there are brown areas on the fourth segments; fifth segments are pale orange.

The maxillipeds have pigmentation around the middle of most segments.

Some spots of pigment are in transverse lines across the abdomen; these are associated with the partly calcified plates.

No pigmentation is discernible on the tail fan.

All green color fades in preserved specimens; brown areas become red, orange, or pale a year after preservation.

The tips of the fingers of the chelipeds and ambulatory legs are dark brown to black.

TYPE.—The holotype and paratype are in the Division of Crustacea, National Museum of Natural History, Smithsonian Institution, USNM 128732, 128733.

TYPE-LOCALITY.—Southwest Caribbean Sea, north of Panama, P–434.

ETYMOLOGY.—The name is from the Latin viridis, referring to the general greenish color of the animal when alive or recently preserved.

DISTRIBUTION.—Known only from the type-locality.