Acanthosquilla crosnieri, Ahyong, 2002

Ahyong, Shane T., 2002, Stomatopoda (Crustacea) from the Marquesas Islands: results of MUSORSTOM 9, Zoosystema 24 (2), pp. 347-372 : 359-361

Acanthosquilla crosnieri n. sp.

( Fig. 7 )

TYPE MATERIAL. — Holotype: Hiva Oa, stn DW1213, 9°50.3’S, 140°03.2’W, 18-20 m, 29.VIII.1997, tl 33 ( MNHN); paratype: Ua Huka , Hane Bay, stn 29, 8°55.70’S, 139°32.00’W, fine and coarse sand, 7-11 m, X.1997, 1 broken cl 6.0 ( MNHN).

OTHER MATERIAL. — Fatu Hiva, 27.5 m, F. E. Lewis coll., 2 badly fragmented specimens ( USNM 125045 ). DIAGNOSIS. — Outer margin of dactylus of raptorial claw with distal lobe triangular, distinctly larger than proximal lobe. AS 6 posterior margin unarmed, with posterolateral spines only. Telson with two pairs of slen- der, fixed primary teeth ; with SM denticles forming inverted V-shaped row; with four spiniform IM denticles in same plane; dorsal surface with five well spaced posteriorly directed spines in fan shaped row above marginal armature. Uropod protopod inner margin with two slender ventral spines adjacent to endopod articulation. MEASUREMENTS. — Male (n = 1) tl 33, female (n = 1) cl 6. Other measurements of holotype: cl 5.5, A1 peduncle 2.5, A2 scale 1.9 .

ETYMOLOGY. — Named for Alain Crosnier who keenly encouraged the study of this material.

DISTRIBUTION. — Known only from the Marquesas.

DESCRIPTION

Eye with cornea slightly flattened anteriorly, inclined laterally on stalk, stalk elongate, extending almost to end of antennular peduncle segment 3. Ophthalmic somite anterior margin rounded. Ocular scales narrow, separate, inclined anteriorly.

A1 peduncle 0.45-0.46cl. A2 protopod with one ventral papilla; A2 scale 0.36-0.41cl.

Rostral plate longer than broad, subpentagonal with short apical spine; lateral margins convergent; dorsal and ventral surfaces smooth.

Raptorial claw dactylus with five teeth; penultimate tooth shorter than preceding tooth, outer margin broadly curved, proximal margin with basal notch, distal lobe triangular, distinctly larger than proximal lobe. PI 128 (male), 133 (female).

Mandibular palp 3-segmented. MXP1-5 each with epipod.

TS6-7 with lateral margins truncate, rounded anterolaterally and posterolaterally. TS8 rounded; sternal keel obsolete.

Endopod of first pleopod in male with elongate tube process and short, blunt hook process.

AS 6 posterior margin smooth; posterolateral spine long, slender; with slender ventrolateral spine and short blunt angular lobe anterior to uropodal articulation; sternum posterior margin unarmed.

Telson with two pairs of slender, fixed primary teeth; with three or four SM denticles either side of midline forming inverted V-shaped row; with four spiniform IM denticles in same plane, first, second and fourth subequal in length, third usually longest; with one spiniform LT denticle; dorsal surface with pair of mid-dorsal pits and five well spaced posteriorly directed spines in fan shaped row above marginal armature.

Uropodal protopod inner margin with two slen- der ventral spines adjacent to endopod articulation; exopod proximal segment outer margin with six movable spines, distalmost exceeding midlength of distal segment; distal margin with short ventral spine; exopod distal segment dark on outer half only; endopod with median dorsal carina.

Colour in alcohol

Anterior cephalon darkly mottled. Raptorial claw and pereiopods with dark mottling. Anterior half of carapace with dark mottled, transverse band, with narrow pale transverse band and posterior quarter with dark transverse band; posterior margin darkest. Thoracic and abdominal somites pale on anterior quarter, with mottled transverse band and dark posteri- or margin, widest medially. Telson dark with pale median line and anteromedial area. Uropodal protopod with dark margins and terminal spines. Uropodal exopod proximal segment and movable lateral spines dark; distal segment dark on outer half only; endopod dark.

REMARKS

Acanthosquilla crosnieri n. sp. closely resembles A. multifasciata from the Indo-West Pacific in almost all respects, but differs in bearing slightly narrower corneae, in bearing a pair of spines under the articulation of the uropodal endopod. The most significant differentiating character is the pair of spines under the endopodal articulation, for the other morphological characters are more difficult to use without comparative material. The two specimens in the USNM are badly fragmented but clearly referable to A. crosnieri n. sp.; in both specimens, the telson and uropods are intact.

Family TETRASQUILLIDAE Manning & Camp, 1993 Genus Heterosquilloides Manning, 1966

Figures

FIG. 7. — Acanthosquilla crosnieri n. sp., tl 33 mm (holotype); A, anterior cephalon, dorsal; B, raptorial claw, right lateral; C, TS6-8, right dorsal; D, AS5-6, telson and uropod, dorsal; E, telson, ventral; F, uropod, left ventral; G, pleopod 1 endopod, right anterior. Scale bar: A-F, 2 mm; G, 1 mm.