Urohaustorius urungari Barnard & Drummond 1982

Urohaustorius urungari

DIAGNOSIS.—Dorsolateral armament rows on articles 1 and 2 of antenna 1 and article 4 of antenna 2 mixing thin spines and setae. Armament row on article 4 of antenna 2 even. Accessory flagellum not reduced. Main flagellar articles of male antenna 1 not thickened, aesthetascs 2 per article and sometimes present on basal articles, article 5 of male bulbous. Coxa 1 broader but not longer than coxa 2, both bearing only tiny setules. Spines on dactyl of pereopod 5 usually set singly in tandem. Dactyls of pereopods 6–7 well developed. Article 2 of pereopod 7 with 3 long stout posteroproximal setae and several setules. Male sternite 6 with low transverse bilaterally lobed, bulbous ridge or flap. Epimeron 2 bearing small to obsolescent tooth, with 2–4 facial setae in jagged horizontal row. Tooth cusp of epimeron 3 obsolescent to small. Inner rami of uropods 1–2 much shorter than outer rami. Dorsolateral margin of peduncle on uropod 2 with stout spine(s). Apicolateral corner of peduncle on uropod 3 with stout spines; outer ramus with setae and spines laterally on article 1. Telson entire, apex extended, apical setules short.

GENERAL DESCRIPTION.—In contrast to U. yurrus, fewer and finer spines on article 1 of antenna 1, especially in female (generally 2E + 2P in female, 3E + 2P in male); fewer spines and more setae on article 4 of antenna 2, especially in female; bulbous, not cylindrical, article 5 of antenna 2 in the (nonterminal?) male; broader article 6 and relatively shorter, stouter dactyl of pereopod 5; 3 (exceptionally 2) posterodorsal setae on article 2 of pereopod 7 (U. yurrus, 2, exceptionally 3); only 2 (rarely 3) apicolateral spines on peduncle of uropod 3 (U. yurrus 4); basal bulge on outer ramus of uropod 3 less angularly defined; telson taller and apically narrower, reaching farther (at least halfway) along the outer ramus of uropod 3.

DESCRIPTION OF MALE.—Holotype male “i,” 2.40 mm: Head about 65% as long as wide, rostrum about 11% as long as remainder of head. Primary flagellum of antenna 1 with 8 articles, formula of aesthetascs = 0–0–2–2–2–1–1–0; accessory flagellum 5-articulate. Facial formula of mixed spines and setae on article 1 of antenna 1 = E, S, 2P; on article 4 of antenna 2 = P, P, E, P–ESEES–PSSEEESESESESS; on article 5 = SESESESSESS; article 3 with 3 facial setae (2 setae and setule); flagellum with 6 articles.

Right incisor simple, left with 2 extremely weak teeth; choppers on molars with 3–4 cusps; formula on right palp article 3 = 6–1–3–1, on left (= missing). Inner plate of maxilla 1 with 1 short apical seta, 1 large apicomedial seta; outer plate with 11 spines. Inner plate of maxilliped with 3 medial setae, outer plate with 1 apicolateral seta; palp article 2 with 4 setae in facial row, article 3 with 2 setae in facial row.

Coxa 1 broadly subtriangular; coxa 2 similar but apex blunter; coxa 3 with 4 ventral setae, 11 in posterior half, posterior margin with 1 seta ventrad; coxa 4 with 4 ventral and 1 posterior setae.

Setal and spine formulas on pereopod 3 = 3, 5, 2–1–1–1, 5 + 4 + 1; on pereopod 4 = 4, 4, 2–1–1–1–1–1, 5 + 4 + 1; posterior margin of articles 5–6 with single row of mostly medium, even serrations. Article 2 of pereopods 5–7 progressively with medium to sparse setal densities posteriorly (8–8–3), article 2 of pereopod 5 lacking mediofacial brush, right dactyl with 4 spines in tandem, left with 5 spines, 2 of these forming pair!

Peduncular spine formulas of pleopods 2–3 (pleopod 1 missing) = 2 and 0, 2 and 1; segmental formulas = 12–8 and 13–12 (inner proliferate on pleopod 3); basal setal formulas = 4–0–1–1 and 7–1–2–3 (see specimen “j” below for complete pleopodal formula).

Epimeron 2 with 4 setae in horizontal facial row.

Peduncle of uropod 1, lateral margin with 6 setae, apicolateral corner with 1 setule; of uropod 2 with 1–2 disjunct lateral spines and 1–2 apicolateral spines plus setule, dorsal setae = 2 and 2, setae of rami = 7–4 and 7–4, inner rami extending 60% and 60% along outer. Peduncle of uropod 3 short and stubby, more than half as wide as long, subequal to, or shorter than, outer ramus, apicolateral corner with 2–3 spines, medial margin naked, ventromedial apical row with 9 mixed setae, article 2 of outer ramus about 33% as long as article 1, about 80% as wide as long, armament formula on lateral margin of article 1 = S–E(S?)–Ee/ES–Ee.

Telson about 1.0 times as wide as long, entire, setal formula = 2P, 1, P, 1 (midapical).

Lateral gland clusters well developed in pleonites 3–6, more weakly developed in peduncle of uropod 3, weak to moderately developed in telson.

Male “j,” 275 mm: With well-developed sternite 6 process (illus.). Facial formula on article 1 of antenna 1 = 3E + 2P. Spine-seta formula for article 4 of antenna 2 = P, P–EE–P–ESEES–PSEEEESESESESS; for article 5 = SESESESESSS; flagellum of 6 articles. Dactyl of pereopod 5 with 5 spines in tandem, left side slightly abnormal, with spines 2 and 3 short. Article 2 of pereopod 7 with 3 dorsoposterior setae. Epimeron 2 with 3 facial setae (2 + 1 socket); epimeron 3 with tiny cusp and slightly excavate posterior margin. Peduncular spine-seta formulas for pleopods 1–3 = 2 and 1, 2 and 0, 2 and 1; segmental formulas = 15–10, 12–9(8), 13–12 (inner proliferate); basal setal formulas = 8–1–2–3, 3–1–1–1, 7–1–1–3. Peduncle of uropod 3 with 3 apicolateral spines, lateral marginal formula for outer rami = ES, Ee/ES, Ee. Telson barely taller than wide, apex flattened, setal formula = 2P, 1, P, 1/2P, 1, P, 1.

Male “h,” 2.55 mm: Article 1 of antenna 1 formula = E (long) EE + 2P. Spine-seta formula on article 4 of antenna 2 = P, P–EE–PSEES–PEEESEEESESESS; on article 5 = SSES–ESESESS; flagellum of 6 articles. Dactyls on right and left fifth pereopods each with 5 spines, none doubled, though in 3 groups, 2–1–2 on 1 side. Article 2 of pereopod 7 with 3 dorsoposterior setae. See illustrations for sternite 6. Peduncle of uropod 3 with 3 spines; lateral marginal spine-seta formula of article 1 = ES, Ee/ES, Ee. Telson barely taller than wide, peaked; telsonic formula = left 2P, 1, P, 1 (unpaired mid apex)/right 1, 2P, 1, P.

DESCRIPTION OF FEMALE.—Large, ovigerous female “g,” unmeasured, with 2 eggs in brood pouch: Setal formula on article 1 of antenna 1 = 2E + 2P; spines on article 2 all very fine, 1 short, 2 medium, 1 long, all distal; flagellum ordinary, with 7 articles; accessory flagellum with 5 articles. Spine-seta row on article 4 of antenna 2 even, formula = P, P, EE, P–5E–PEE–ES3ESS (extreme reduction of spines); article 5 tending to ovate in shape, about 60% as wide as long, 60% as long as article 4, formula = S3eS3ESEESS (abnormally large number of elements due to increased number of setae). Right and left dactyls of pereopod 5 each with 6 spines, distal 2 “paired” (see note on p. 80) on each side. Right pereopod 7 with 3 dorsoposterior setae on article 2, left missing. Posteroventral cusps on epimera 2 and 3 obsolescent. Epimeron 2 with 4 setae in jagged row. Peduncular spine/seta formulas for pleopods 1–3 = 2 and 1, 2 and 0, 2 and 1; segmental formulas = 17–12, 14–9, 16–15 (inner ramus proliferate on both sides); basal setal formulas = 8–(1 + 1 setule)–1–3, 2–0–1–1, 7–0–2–(2 + 1 setule). Peduncle of uropod 1 subequal in length to outer ramus, much more than half as wide as long, with 8 lateral setae, 1 apicolateral setule, and 2 large facial setae, in addition to ordinary medial armament; peduncle of uropod 2 with large dorsal seta, laterally with 1 midmarginal spine and 2 apicolateral spines plus 1 spinule. Outer rami of first and second uropods with triad of setae at apex and 6 medial setae; inner rami of both uropods about 60% as long as outer, each with 5 medial setae. Peduncle of uropod 3 glandular, with 2 apicolateral spines; inner ramus extending beyond apex on article 1 of outer ramus; formula for lateral margin of article 1 = Ee, Ee/Ee, E; article 2 about 30% as long as article 1. Telson slightly taller than wide, heavily glandular, apically narrow, setation symmetrical; formula = 2P, 1, P, 1/2P, 1, P, 1.

Female “n,” 2.60 mm: Article 1 of antenna 1 with formula = E (long) + 2E + 2P; article 2 with 4 very fine spines, 1 short, 2 medium, 1 long, all distal; flagellum of 7 articles, aesthetascs very long, formula = 0–0–2–2–1–1–0; accessory flagellum of 5 articles. Spine-seta formula on article 4 of antenna 2 = P–P–E–P–4ES–PSES3E SESESS; article 5 cylindrical, though very slightly broader towards distal apex, apex itself slightly rounded, spine-seta formula = SSEESEESESS. Setal and spine formulas on pereopod 3 = 5, 5, 2–1–1–1, 4 + 4 + 1; on pereopod 4 = 4, 5, 2–1–1–1, 4 + 4 + 1. Article 6 of pereopod 5 about 75% as wide as long, only 1 dactyl present, with 5 spines in tandem. Article 2 of pereopod 7 with 3 dorsoposterior setae. Cusps obsolescent on epimera 2 and 3; epimeron 2 with 2 and 3 setae. Peduncular spine and seta formulas for pleopods 1–3 = 2 and 1, 2 and 0, 2 and 1; segmental formulas = 15–11, 13–9, 15–13 (inner proliferate); basal setal formulas = 8–1–2–3, 3–0–0–1, 6–0–2–2. Peduncle of uropod 1 bearing 6 (7) lateral, 2 large dorsal, and 5 medial setae, 1 medioapical medium-length seta plus 1 setule; outer and inner rami each with 5 medial marginal setae. Peduncle of uropod 2 with 1 midlateral spine, 2 spines plus 1 spinule on apex, and 1 large dorsal seta. Outer rami of first and second uropods broad apically, with a triad of setae. Peduncle of uropod 3 with 2 apicolateral spines; article 1 of outer ramus on left side with 1 lateral marginal spinule, lateral margin on right side naked; article 2 of outer ramus unusually long, about 45% as long as article 1; inner ramus extending beyond apex of article 1. Telson about as wide as tall, glandular, asymmetrically setose; telsonic formula = 2P, 1, P, 1, 1 (midapical)/1, 2P, 1, P.

Female “v,” 2.75 mm: With symetrically setose, tall, flat-apexed, sparsely glandular telson, conforming to diagnosis and description of U. urungari, but outer ramus of uropod 3 bearing spines as well as setae (only known female so equipped); formula for lateral margin of article 1 = ES, Ee/s, ES, Ee. Spine-seta formula for article 4 of antenna 2 = P, P, P–EEEES–PSEEESEESESESS. Left dactyl of pereopod 5 with 4 spines, right abnormal or damaged. Article 2 of pereopod 7 with 3 dorsoposterior setae. Epimeron 2 with 2 setae. Outer rami of uropods 1 and 2 apically broad with 3 setae almost side by side. Peduncle of uropod 3 with 2 apicolateral spines.

Female “f,” 2.66 mm: Formula on article 1 of antenna 1 = E (long), E, 2P; all elements on article 2 very thin. Article 3 of antenna 2 with 1 facial setal spine, formula on article 4 (even) = P, P, P, P–ESEE–PEESEE–ESESESS, setae dominant, on article 5 = SEESESESS, article 5 ovate (not bulbous form of male).

Dactyl of pereopod 5 with 5 spines in tandem; article 2 of pereopod 6 of thin form.

Peduncular spine formula of pleopod 1 = 2 and 1, segmental formula = 14–10, setal formula of rami = 7–1–2–3 (to substitute for missing male pleopod 1); other female pleopods badly damaged.

Uropod 1 peduncle lateral setae = 6, dorsal = 2, rami = 8 and 4; uropod 2 peduncle lateral = 1 spine, apicolateral = 2 spines and setule, dorsal setae = 2; ramal setae = 7 and 4. Uropod 3 peduncle apicolateral spines = 2, inner ramus like male; setae formula on lateral article 1 of outer ramus = e–E.

Telson as long as broad, armament formula = 2P, 1, P, 1 (unpaired middle).

DISTRIBUTION.—Queensland, Moreton Bay, Middle Banks, 6–15 m, mud, sand.

Urohaustorius species M

Known as the Malabar form, 4 specimens from the Australian Shelf Benthic Survey off Malabar, NSW, cannot be firmly identified with any of the foregoing species in Urohaustorius. These specimens, all females, appear, apart from the entire telson, to have more in common with U. pulcus and U. pentinus, and particularly the latter, than with the U. merkanius group. The largest specimen, female “x,” 2.31 mm, has a broad telson narrowing towards the apex, whereas the other 3 specimens have the ordinary, mostly rounded, broad telson; but in all 4 specimens the telson is apically flattened. The presence of several short stout spines on article 2 of antenna 1 appears to separate these specimens from either U. merkanius or U. parnggius, and the absence of doubled spine positions on the dactyl of pereopod 5 and the spinous article 1 on the outer ramus of uropod 3 remove the specimen from U. merkanius (unless they are neotenous adults). The normal spination pattern on article 4 of antenna 2 distinguishes the specimens from U. parnggius and U. wingaro.

Distinctive characters of this morph are (1) narrow article 2 of pereopod 6; (2) presence of 2 very long, stout, plumose setae at the proximal end of the spine group on article 1 of antenna 1.

The inconsistency of the armament formulas on article 1 of antenna 1 is, however, anomalous, as seen in the following tabulation of female specimens.

Specimen Antenna I Opposite antenna 1

“x” 2E(long), 2S, 2P

E(short), 3S, 2P

“c” 2E, 2S, 2P

2E(long), 2E(short), 2P

“y” 2E, S, 2P

E, 3S, 2P

“d” 2E, 2S, 2P

2E, 2S, 2P

Only female “d” appears to be normal and consistent with expectation in stability. One proximal long seta has been observed in a specimen of U. metungi (illus.); and 2, as in the Malabar form, in 2 juveniles of what is probably U. pulcus from Western Port, and in a sample of brood young of U. yurrus from Queensland. In U. perkeus article 1 carries only such long setae. We consider the possibility that this is a juvenile character and that specimens of U. species M are mutant neotenes. More specimens are awaited.

DESCRIPTION OF FEMALE.—Female “c,” 1.90 mm: Armament row on article 1 of antenna 1 = 2E, 2e, 2P/2E, 2S, 2P. Armament row on article 4 of antenna 2 with all elements aligned, formula = P, PEE–PSESS–PSSESESESESESS. Dactyl of pereopod 5 with 3 spines in tandem. Epimeron 2 with 4 setae; tooth of epimeron 3 sharp. Uropod 1 as in typical specimens of U. merkanius; peduncle with 5 lateral and 3 dorsal setae; inner ramus not as short as usual. Peduncle of uropod 2 with either 1 or 2 apicolateral spines and 1 lateral spine; inner ramus shorter than in U. merkanius; setae on rami of uropods 1 and 2 = 6 and 3, 6 and 2. Apicolateral corner on peduncle of uropod 3 with 4 spines; article 1 of outer ramus with only 2 sets of armaments. Telson truncate as in specimen “u” of U. pentinus but not distinctly excavate; setal formula = 2P, 1, P, 1.

Superfemale “x” of dwarf form, 2.31 mm: Armament row on article 1 of antenna 1 with 2 long plumes, 4 short spines, 2 penicillate setules. Armament row on article 4 of antenna 2 with all elements aligned, formula = P–PEE–PSESEESS–PSSEESEESESESESS; article 5 = 3SESESEESEES. Dactyl of pereopod 5 with 4 spines in tandem. Epimeron 2 with 4 setae. Peduncle of uropod 2 with 3 apicolateral spines and 1 lateral spine. Telson entire, formula = 2P, 1, P, 1.

VOUCHER MATERIAL.—AM SBS E2S3 and E2S4, female “x,” 2.31 mm; female “c,” 1.90 mm (illus.); female “d,” 1.75 mm; female “y,” 1.73 mm.

MATERIAL.—SBS, 2 samples (4).

DISTRIBUTION.—NSW, off Malabar, ~20 fathoms (37 m), coarse sand.