Paradexamine dandaloo J. L. Barnard 1972

Paradexamine dandaloo

DESCRIPTION (of female). — Lateral cephalic lobe rounded, head lacking anteroventral definition at base of antenna 2 (but support extended medially), rostrum medium, thin, blunt; article 1 of antenna 1 with ventral spines sharp, stout, and arranged in tandem, about 5 positions, terminal position paired; article 2 about 0.75 times as long as article 1, apically simple, and bearing pair of spines ventroproximally, flagellum about 2.8 times as long as peduncle; flagellum of antenna 2 about 2.5 times as long as peduncle, multiarticulate; mandibles with 2 long spines on right, 3 on left, no accessory bulge, molar strongly triturative, ragged seta each side, ordinary setae each side, slightly shorter on left; outer lobes of lower lip each with 3 apicomedial cones, one long, others vestigial or short, mandibular lobes thin, sharp, and apically upturned; palp of maxilla 1 large, of medium width, exceeding apex of outer plate, bearing apical and medial setae and long apical cone, inner plate unusually small, bearing 2 setae; maxilla 2 thin, inner plate narrower than outer, both appressed, inner with apex tapering (or very oblique), outer uncurved, inner reaching nearly 90 percent along outer; inner plate of maxilliped of medium to large size, apically tapered, bearing 2 facial setae and about 6 terminolateral setae; outer plate of ordinary size, spines simple, of medium-to-small size, palp robust, strongly exceeding outer plate; coxa 1 weakly expanded apically, naked anteriorly, ventral margin scarcely scalloped and setules obsolescent, posterior margin with 1 stout spine, coxae 2-3 rectangular, also poorly setose, each with 1 posterior spine; coxae 5-6 with strongly spinose posteroventral margins: gnathopod 1 with article 6 about 0.86 times as long as article 5, gnathopod 2 about the same, gnathopods slightly stout, palms very oblique, medial faces of hands, respectively, with 10-11 and 11-12 plumose spines in spine row, anterior faces with 3 and 2 rows of setae on gnathopods 1 and 2, dactyls smooth proximal to main inner tooth, palms minutely serrate; pereopods 1-5 thin, with sharp spines, ratio of articles 4-7 on pereopods 1-2 about 15:15:21:12; article 2 of pereopod 3 of ordinary stoutness, posteroventral lobe broad and deep, article 2 of pereopod 4 quadrovate, posteroventral lobe well developed, spinose; article 2 of pereopod 5 rectangular, of medium width, posterior margin serrate, posteroventral quadrate corner spinose, ratio of articles 4-7 about 25:35:31:15; pleonal epimera 1-2 with lateral ridge, medium sharp tooth on each posteroventral corner, epimeron 3 with thick, small blunt tooth, posterior margins of epimera mainly smooth, epimeron 1 with facial row of about 9 spines and 4 other spines arranged irregularly, epimeron 2 with row of 4 and 3 accessory spines trailing anteriad plus 2 other groups of 2 and 1 spines each, epimeron 3 with formula, posterior to anterior, of 3,2,2,1; pleonite 1 dorsally smooth, pleonite 2 with sharp dorsal and sharp sidetooth, pleonite 3 with blunt dorsal tooth on heavy shoulder, shoulder often multifid, pleonite 4 with dorsal crest formed of mutifid shoulder, no lateral tooth, but lateral spine present on weak ridge, pleonites 5-6 (fused) with 2 dorsolateral spines on each side; dorsal margin of peduncle on uropod 1 evenly spinose; rami of uropod 3 lacking setae; telson with narrow apices, each apex with about 8 small cusps including enlarged laterals, main spine large and covering nearly half of apical width, lateral margins with 6-8 long to medium spines in tandem; cuticle of body segments, head, coxae, article 2 of pereopods 3-5 covered with highly visible slit-pits.

MALE (5.8 mm, Shepherd 14, one specimen known). — With ordinary male characters such as enlarged eyes, elongate antennae, especial enlargement and disproportion of articles 4-5 of antenna 2; left mandible bearing only 1 ragged seta, no ordinary setae; lower lip lacking small cone accessory to main cone; palp of maxilla 1 with one side bearing 2 long cusps, other side bearing 1 long, 1 short cusp on palpar apices; maxilla 2 normal; maxilliped with inner plates strongly enlarged, palp otherwise like that of female; coxa 1 more strongly expanded than in female; gnathopods apically elongate, similar to each other, article 6 of equivalent size and length but article 5 longer in gnathopod 2 than gnathopod 1, ratio of articles 5 and 6 in gnathopod 1 about 130:78, in gnathopod 2 about 143:78; see Figure 29mN1 for gnathopod 1; comparison of gnathopod 2: 9 spines in oblique facial row; formula of anterior facial setae, apical to proximal: 1-4-2, posterior margin of hand with 5 setae; pereopods generally spinier than in female, and dactyls of pereopods with numerous extra enlarged setae on outer margins, pereopods 1-2 with 2 extra pairs, pereopod 3 with 4 extra pairs, pereopods 4-5 with 5 sets having formula proximal to apical of 1-2-3-3-1; second articles of pereopods 3-5 larger in relation to coxae than in female, article 2 of pereopod 4 with larger posteroventral lobe; serrations of telson reduced to about 3; uropod 3 missing; spines on urosome very small; uropod 1 with 4 proximolateral spines on peduncle; facial spine formulae on epimera 1-3, rear to front, epimeron 1: 1-12-5 plus 5 marginal irregular groups, epimeron 2: 13-1-1-1-1, epimeron 3: 4-4-3-3-2-1-1.

HOLOTYPE. — SAM, female, 6.4 mm.

TYPE-LOCALITY. — Shepherd 46, Judith Cove, West Island, South Australia, 15 feet.

RELATIONSHIP. — Presumably this species has affinities with those members of Paradexamine in which the side tooth of pleonite 4 is absent and which lack a cephocular cusp. Only three other Australian species have that combination of characters: P. churinga, P. echuca, and P. thadalee. Like P. dandaloo, P. thadalee has surficial slit-pits, but it differs from P. dandaloo in the broad telsonic apices and the multispinose lateral spine positions, the slightly less oblique gnathopodal palms with enlarged and fewer castellations, the larger inner plate of maxilla 1 bearing a side seta (not terminal), the short palp of maxilla 1, the highly reduced inner plate of the maxilliped, and the absence of medial setae on the inner plate of maxilla 2.

Paradexamine churinga differs from P. dandaloo in the broad, nonsetose inner plate of maxilla 1, the absence of ordinary setae on the left mandible, the small inner plate of the maxilliped in the female, the extremely distal position of the dactylar ornamentation of the pereopods, and the highly apical location of the distalmost lateral spine on each side of the telson.

Paradexamine echuca differs from P. dandaloo in the sharp rostrum, the facial setae on the inner plate of maxilla 2, and the presence of apicolateral serrations on the telson.

MATERIAL. — Shepherd 2 (1), 3 (1), 7 (2), 9 (4), 14 (1), 15 (1), 22 (1), 31 (3), 40 (3), 46 (5); VicFish 87 (1).

DISTRIBUTION. — South Australia and Victoria, sublittoral.