Stenothoe miersi (Haswell 1879)

Stenothoe miersi (Haswell)

?Montagua Miersii Haswell, 1880c:325, pl. 24: fig. 4.

NOMENCLATURE.—Original material of this species is missing from either the Macleay Museum or The Australian Museum and only a few points of possible similarity to Haswell’s description and figures can be made. If Haswell’s original material remains missing and the species I have in hand is eventually found again in the type-locality, Port Jackson, then this species may as well be linked to Haswell’s name.

Montagua longicornis Haswell (1880c:323, pl. 24: fig. 5) is not presently aligned to my material nor to M. miersi because of the large number of spines on the rami of uropods 1–2.

DESCRIPTION OF FEMALE.—Lateral cephalic lobe strongly projecting, submammilliform, but obliquely subtruncate apically, anteroventral corner of head smoothly quadrate; prebuccal mass not bulky, epistomal and labral parts separated by weak notch, epistomal part forming subconical, almost sharp lamella projecting in front of similarly sharp midcephalic keel; mediodistal part of article 1 on antenna 1 not strongly extended; accessory flagellum nearly square, bearing two long aesthetascs; lobes of upper lip of ordinary length, projecting unequally; inner plate of maxilla 1 asymmetrically ovate, bearing one long stiff seta, palp with about six marginal spines extending mediobasally more than halfway, apicolateral margin beveled, article 1 tumid; inner plate of maxilla 2 scarcely projecting medially, appearing simply as setose margin, outer plate short, broad, setal spines of medium length; inner plates of maxilliped short, broad, bearing none or one apical setae, outer plate obsolescent, article bearing outer plate facially naked; coxae 1–4 of ordinary dimensions, ventral margin of coxa 4 convex; article 5 of gnathopod 1 with broad, scarcely projecting posterior lobe, hand long, palm strongly oblique and weakly marked from posterior margin of hand, dactyl with one to three large facial setae, inner margin with subapical tooth, anteromedial margin of hand with three or four setae in tandem, no groups; article 4 of gnathopod 2 extended subacutely beyond tangent of article 5, latter with shortened and very narrow posterior lobe, hand elongate, palm very oblique and not distinct from posterior margin of hand, moderately setose, in largest adults developing small cusp distalwards but retaining defining spine of juvenile, dactyl very long, extending proximally from defining spine, riding onto medial face of hand, apically notched, bearing one or two weak outer setae at marks 33 and 60; pereopods 1–2 not grossly distinct from each other, pair of locking spines on all pereopods distinct from nearby marginal spines, apically simple, slightly sharp or weakly blunt, dactyl with membranous and recumbent distal setule; article 2 of pereopods 4–5 equally broad, anterolateral facial ridge curving posteriorly away from anterior margin; peduncle of uropod 1 with sharp ventral tooth between rami, distolateral margin of peduncle with one spine or pair of spines crowded together, no ramus of uropods 1–2 shortened, outer generally with two spines, inner with one; peduncle of uropod 3 with two dorsomarginal spines in tandem and pair of distal spines, article 1 of ramus with one pair of dorsodistal spines; telson of medium length and breadth, with three spines basolaterally on each side, groups of distad setules irregularly arranged; epimera 1–3 each softly quadrate posteroventrally, epimeron 1 with one ventral setule.

MALE.—Coxa 3 narrower than in female, coxae 3–4 with weak ventral stridulation ridges, inner plate of maxilliped with two setae; gnathopod 2 with hand highly elongate and heavily setose and bearing deep distal notch guarded proximally by narrow tooth; uropod 3 like that of female, not rugose.

JUVENILE.—Article 1 of antenna 1 with only one long and thin spine; outer plate of maxilla 2 with six setae, inner plate with three setae; inner plate of maxilliped with two long setae, outer plates vestigial as in adult; each ramus of uropods 1–2 with one spine; telson with only two lateral spines on each side; lobe on article 5 of gnathopod 2 extending evenly to process of article 4, dactyl with inner tooth not formed into notch as in adult; accessory flagellum like that of adult.

RELATIONSHIP.—This species earlier was a synonym of S. valida Dana (see J. L. Barnard, 1953), but it can now be shown to be distinct from S. valida. The close relationship is best indicated by the odd shape of maxilla 2, shared also by S. gallensis Walker (=S. cattai Stebbing).

Stenothoe ?miersi differs from S. valida in the poor apical expansion of coxa 3 but the slight expansion present in S. miersi is a definite mark of affinity. Coxa 2 of S. miersi is of ordinary shape for Stenothoe and not posteroventrally sinuous as in S. valida, article 4 of pereopods 3–5 is poorly expanded and more like that of the specimens identified from Hawaii as S. ?valida by J. L. Barnard (1970). The sharp ventral tooth on the peduncle of uropod 1 distinguishes S. miersi from both S. valida and S. gallensis. The palmar ornament on male gnathopod 2 resembles that of S. valida more than that of S. gallensis and male uropod 3 does not have a rugose article 2 as in S. gallensis.

The specimens identified by Chevreux and Fage (1925) as S. cattai should be given a new name; they differ from S. valida, S. gallensis, and S. miersi in the presence of several middorsal and several facial spines on article 1 of the ramus of uropod 3.

Stenothoe adhaerens Stebbing (1888) differs from S. gallensis, S. valida, and S. miersi in the shortened outer ramus of uropod 2. It has the enlarged article 4 of pereopods 3–5 similar to that in S. valida; it also has the sinuous coxa 2.

Stenothoe ascidiae (Pirlot) apparently also belongs to the S. gallensis group and, like S. adhaerens, has a shortened outer ramus of uropod 2; it also bears a long uniarticulate accessory flagellum, the reason Pirlot described his species as type of Microstenothoe. Stenothoe ascidiae is not yet distinguishable from S. adhaerens but the great geographic distance between them suggests they are probably distinct.

MATERIAL.—JLB Australia 10 (1), 11 (2).

DISTRIBUTION.—Port Jackson; southwestern Australia.