Stenothoe miersii ( Haswell, 1879 )

Krapp-Schickel, Traudl, 2009, Stenothoidae *, Zootaxa 2260 (1), pp. 872-879 : 873-874

Stenothoe miersii ( Haswell, 1879)

( Figs 1 , 2 )

Montagua Miersii Haswell, 1879: 323 , pl. 24, fig. 4.

Montagua longicornis Haswell, 1879: 323 , pl. 24, fig. 5.

Stenothoe miersi . — Stebbing, 1906: 200 (in part). — Stebbing, 1910: 637 (in part).

Stenothoe ? miersii . —J.L. Barnard, 1974: 120, figs 75–76.

Stenothoe miersi . — Lowry & Stoddart, 2003: 260.

Stenothoe valida . — Sheard, 1937: 21 (= S. miersii , but confused with other species).

not Montaguana miersii . — Chilton, 1883: 79 (part = S. moe, J.L Barnard, 1972 ).

not Montagua miersii . — Chilton, 1884: 1043 (part = S. moe, J.L Barnard, 1972 ).

not Probolium miersii . — Thomson & Chilton, 1886: 150 (= S. valida ).

Material examined. 1 female, incomplete, AM P71403 (QLD 1806) ; 1 female, AM P71495 (QLD 1819) ; 1 female, 1 juvenile male, 3.5 mm, slides, AM P71536 (QLD 1820) ; 1 female, incomplete, AM P71546 (QLD 1823) .

Type locality. Port Jackson , New South Wales, Australia (~ 33°51'S 151°15'E) .

Description. Based on juvenile male, 3.5 mm, AM P71536.

Head. Antenna 1 longer than head and pereonites 1–4, longer than antenna 2; peduncle not geniculate; peduncular article 1 without anterodistal or posterodistal lobes; peduncular article 2 without anterodistal lobe; flagellum with 11 articles; accessory flagellum present and minute, 1–articulate. Mandible palp absent, with conical hump where insertion of a palp would normally occur. Maxilla 1 palp 2–articulate. Maxilla 2 outer plate sitting upon inner one. Maxilliped inner plate subquadrate, with 0–1 distal seta; outer plate lacking.

Pereon. Pereonite 4 not elongate, similar in length to pereonite 3; without dorsal carina. Gnathopods 1–2 dissimilar in shape. Gnathopod 1 subchelate; merus enlarged, little produced distally; carpus short, triangular; propodus about 2 x as long as broad. Gnathopod 2 propodus posterior margin oblique/rounded, with or without posterodistal expansion, about 3 x as long as broad, not transverse, posterior margin without corner, with small or no sinus, evenly rounded, with dense row of fine setae; dactylus reaching distinctly further than half length of propodus, posterior margin not or minutely serrate. Pereopod 4 coxa ventral margin convex. Pereopod 5 basis not expanded, but linear. Pereopod 6 basis fully expanded. Pereopod 7 basis fully expanded; merus distally twice as wide as ischium, with scattered robust setae on posterior margin, expansion reaching to or past mid length of carpus; dactylus large (subequal or larger than carpus).

Pleon. Pleonite 3 without dorsal elevation. Epimeron 3 posteroventral corner subquadrate/rounded. Urosomites free. Urosomite 1 without dorsal carina. Uropod 1 peduncle with distoventral spine. Uropods 1–2 inner rami well developed, subequal in length to outer rami. Uropod 3 with peduncle and single ramus; ramus longer than peduncle, 2 articulate, article 2 subequal in length or shorter than article 1. Telson laminar, with dorsolateral robust setae, apically acute or subacute.

Female (sexually dimorphic characters). Based on female, AM P71536. Antennae subequal. Gnathopod 2 palm regularly rounded and shorter than in male.

Habitat. Marine; among algae, colonial and stalked ascidians, bryozoans, plate corals, gorgonaceans, sponges, spirorbid and Diopatra worm tubes and rocks. Littoral, intertidal to 15 m.

Remarks. In Haswell (1879) two species of Montagua were described from Port Jackson: M. miersii followed directly by M. longicornis . It appears that the first was the female, the latter the male of the same species, belonging to Stenothoe . J.L. Barnard (1974) described four species of Stenothoe from Australia. One of these he called S.? miersi . Haswell's types come from the east coast of Australia, but Barnard's material was from Cottesloe Beach and Middleton Beach in south-western Australia. Barnard's description matches with different populations around most of the Australian coastline, and also with the Lizard Island specimens. This species seems to be Haswell's species and S. miersii is therefore the most wide-spread Australian stenothoid species.

This species shows a clear sexual dimorphism and its maxilla 2 has the outer lobe sitting upon the inner one. These two characters are not always combined among species in the genus. On the Great Barrier Reef it is the only species of Stenothoe found to date.

Distribution. Australia. Queensland: Lizard Island (current study). New South Wales ( Haswell 1879). Western Australia (J.L. Barnard 1974).

Figures

FIGURE 1. Stenothoe miersii (Haswell, 1879), juvenile male, 2.5 mm and ovigerous female, 3 mm, both AM P71536, Half Mile Opening, Yonge Reef, Lizard Island, Great Barrier Reef.

FIGURE 2. Stenothoe miersii (Haswell, 1879), juvenile male, 2.5 mm and ovigerous female, 3 mm, both AM P71536, Half Mile Opening, Yonge Reef, Lizard Island, Great Barrier Reef.