Comprehensive Description

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Description

Yammacoona kunarella, new species

 

Description of female—Head about 12 percent of total body length, greatest width about 75 percent of length; rostrum unconstricted, broad, short, antenna 1 attached directly to apex of rostrum. Eyes large, mostly occluded with pigment. Article 1 on peduncle of antenna 1 about 1.45 times as long as wide, about 1.4 times as wide as article 2, ventral margin with 3 apical setules, weakly produced dorsal apex with one setule; article 2 about 0.6 times as long as article 1, with ventral cluster of 3-6 setae on hump; primary flagellum with 9-11 articles, about 0.8 times as long as peduncle, bearing aesthetascs; accessory flagellum with 9-11 articles. Spine formula on article 4 of antenna 2 = 1-3-9 or 1-3-8 or 1-2-9, dorsal margin with notch bearing 2 spine-setae, ventral marign with 3 medium setae and one spine, one ventrodistal medium spine; article 5 about 0.7 times as long as article 4, facial spine formula = 5 or 4, dorsal margin naked, ventral margin with 2 sets of 2 long and short setae, 3 ventrodistal short to medium spines; flagellum about 1.4 times as long as articles 4-5 of peduncle combined, with 9-11 articles. Mandibles with strong palpar hump; right incisor with 3 teeth; left incisor with 5 humps in 2 branches; right lacinia mobilis bifid, distal branch little shorter than proximal, distal branch flabellate, denticulate, proximal branch flabellate, with marginal denticles and facial humps; left lacinia mobilis with 5 teeth; right rakers 7 plus one rudimentary; left rakers 7 plus 2-3 rudimentaries; molar in form of elongate plaque bearing bulbous fuzzy hump, right molar with 5 medium to short spines plus one short spine strongly disjunct, left molar with 3 medium spines plus one short spine strongly disjunct, each molar with plume; palp article 1 elongate, article 2 with one short inner apical seta and one other shorter inner seta, article 3 about 0.85 times as long as article 2, truncate apex with 6 spine-setae, middorsal formula = 2 spines. Inner plate of maxilla 1 enlarged, bearing one long apical pluseta, one shorter apicomedial seta, 2 much shorter apicolateral setae; palp short and stout, palp article 2 with 5 long apical and subapical setae. Plates of maxilla 2 extending subequally, of equal breadth, outer with 2 apicolateral setae, inner with one medial seta. Inner plate of maxilliped with one apical spine, 2—3 apicofacial setae, 2 medial setae; outer plate very small and almost hidden behind inner plate, with 3-4 medial and apical spines, one apicolateral seta; palp article 1 with apicolateral seta, article 2 elongate, with one apicolateral seta, medial margin of article 2 weakly setose, article 3 strongly protuberant, with one facial seta, one lateral seta, nail of article 4 medium, with 2 accessory setules. Coxae 1-4 short and broad, coxa 1 strongly expanded apically, anterior margin straight; main ventral setae of coxae 1-4 = 1-1-1-0; anterior and posterior margins of coxa 4 strongly divergent, posterior margin very oblique, almost straight, posterodorsal corner rounded, posterodorsal margin short, convex, width-length ratio of coxa 4 = 1:1; long posterior setae on article 2 of gnathopods 1-2 and pereopods 1_2 = (2-3)-(2-3)-2-3, short anteriors = (0-l)-(2-3)-(3-6)-(4-5), long anteriors = 0-0-1-0, short anteriors = 3-3-5-3, no others. Gnathopod 2 enlarged, hand of gnathopod 1 slightly enlarged; width ratios of articles 5-6 on gnathopods 1-2 = 23:39 and 22:50, length ratios = 47:62 and 34:80; palmar humps very large, palms strongly oblique; article 5 of gnathopod 1 triangular, posterior margin lobate; article 5 of gnathopod 2 short, triangular, lobate, cryptic. Pereopods 1-2 similar; posterior setae on pereopod 1 article 4 mainly apical, on pereopod 2 extending apically to mid mark, in groups 2-2-2-1; facial setae formula on article 4 = 3 and 3, on article 5 = 1 and 2; main spine of article 5 extending to M. 100+ on article 6, article 5 with 3-4 proximoposterior spines; spine formula of article 6 = 3 + 3, no middistal seta, most spines long; acclivity on inner margin of dactyls of pereopods 1-2 sharp, produced as tooth, emergent setule long, midfacial pluseta ordinary. Coxae 5-7 posteroventral setule formula = 3-5-5. Articles 4-5 of pereopods 3-4 broad, facial spine rows dense, facial ridge formula on article 2 of pereopods 3-5 = 0-1-2; width ratios of articles 2, 4, 5, 6 of pereopod 3 = 50:50:50:22, of pereopod 4 = 67:58:50:20, of pereopod 5 = 73:18: 17:10, length ratios of pereopod 3 = 78:43:38:45, of pereopod 4 = 85:52:42:48, of pereopod 5 = 105:24: 24:30; article 2 of pereopod 5 exceeding apex of article 5, dactyl weak, medial apex of article 6 smooth, posteroventral corner of epimeron 1 rounded, protuberant, posterior margin weakly sinuous, corner with setule and second setule above, anteroventral margin with 3 medium setae, posteroventral face with 1-2 long setae in vertical pair; posteroventral corner of epimeron 2 rounded, weakly protuberant, guarded by setule sinus, posterior margin weakly convex, facial setae = 5, posteriormost pair or triad set vertically, setae crowded forward; posteroventral corner of epimeron 3 rounded, weakly protuberant, with setule sinus, posterior margin almost straight, face with oblique, almost vertical row of 3-6 setae. Urosomite 1 with ventral setule at base of uropod 1, articulation line complete; urosomite 3 scarcely protuberant dorsally. Rami of uropods 1-2 with articulate enlarged apical nails, inner rami of uropods 1-2 with one accessory nail, outer ramus of uropod 1 with 1-2 dorsal spines, inner with one, outer ramus of uropod 2 with one dorsal spine, inner with no dorsomedial spine; peduncle of uropod 1 with one apicolateral spine and microscopic basofacial setule, medially with marginal setule and apical spine; peduncle of uropod 2 with 4-7 dorsal spines, medially with one apical setule; apicolateral corners of peduncles on uropods 1-2 lacking comb. Peduncle of uropod 3 with 2 ventral spines, dorsally with one lateral setule, one medial spine; rami feminine, inner extending to M. 65 or less on article 1 of outer ramus, apex with one long seta, medial and lateral margins naked, article 2 of outer ramus short, 0.17, bearing 3 long setae, medial margin of article 1 naked, lateral margin with 3 acclivities, spine formula = 2-2-2-2, setal formula = 0. Telson short and broad, length-width ratio = 7:8, not fully cleft, each apex wide, rounded-truncate, lateral acclivity absent, bearing short lateral setule, spine next medial much longer than setule, set subapically, with adjacent very short medial setule, midlateral setules diverse. Cuticle with ordinary bulbar setules, emergent setules especially short.

 

Observations (female)—Lateral cephalic lobe thick, anteriorly truncate, strongly extended forward. Apex of each flagellum with short aesthetasc not counted as article. Mouthparts placed highly ventrad, prebuccal complex almost horizontal, strongly extended forward. Molar and spines crowded towards incisor. Article 2 of pereopods 1-2 with additional small posterior straw-shaped setae paired with long members and extending 3-4 in number above long setae. Anterior margin of epimeron 1 with 1-10+ straw-like setules (highly variable), ventral margin with 3-7 straw-like setules; setae on face of epimeron 2 variable, additional variations as follows: 3 vertical and 2 horizontal, or 2 horizontal and 2 vertical, or 4 vertical and one thrust forward horizonally. Basofacial setule on uropod 1 so small as to be almost invisible.

 

Description of male—Head exceptionally elongate, up to 21 percent of total body length, eyes enlarged, anterior cephalic extension marked off by ventral constriction. Articles 1-2 of antenna 1 of subequal width, article 1 relatively narrower than in female, bearing medioventral patch of long fuzz, article 2 not as strongly humped ventrally as in female, bearing 5 posterior setae in cycle; primary flagellum with 11 articles, terminal members bearing aesthetascs, one calceolus on each of articles 1-7; accessory flagellum 8-9 articulate. Article 3 of antenna 2 with only 2 small facial setules, articles 4-5 greatly broadened, spines short and broad, spine formula of article 4 = 1-3-9, of article 5 = 7, dorsomedial faces of articles 3-4 with setular fuzz, dorsal margin of article 5 with one calceolus, ventral margin of article 4 with 2 club spines and 2 setules, ventral margin of article 5 with one acclivity bearing spine and setule, ventrodistal margin with 2 spines, seta and setule; flagellum highly elongate, with 30 or 35 articles, one calceolus each on alternate articles, either odd or even, including penultimate article, basally calceoli irregular, for example on articles 3, 4, 6, 8 . . . or 3, 6, 8, 10 . . . or 3, 5, 7, 9 Raker row of right mandible with 5 spines; left with 4 + 2 rudimentaries; right and left molars with 4 spines + one disjunct; left lacinia mobilis with 4 teeth and supernumeraries; palps with articles 1-3 more elongate than in female, article 1 about 65 percent as long as article 2, latter with 2 small and one large inner setae, article 3 with 2 outer acclivities bearing 1 and 3 spine-setae. Palp of maxilla 1 with 4 apical setae. Plates of maxilla 2 much thinner than in female. Inner plate of Maxilliped with only 2 apical setae. Single longer seta on each of coxae 1-3 shorter than in female, coxae much shorter than in female, broader than tall (see illustrations). Long posterior setae of article 2 on gnathopods 1-2 = (2)—(1—2), posterior margin also bearing 6-8 stiff straw-like setae; articles 5-6 of gnathopods of much different proportions from female, both gnathopods with broad article 6 and elongate article 5, length ratios of articles 5-6 of gnathopods 1-2 = 53:68 and 47:68, width ratios = 26:47 and 22:51; article 5 of gnathopod 1 with medium-broad posterior lobe, of gnathopod 2 with narrow protuberant lobe, article 5 almost cryptic on gnathopod 2. Long posterior setae of article 2 on pereopods 1-2 = 2 and 2 with 10-11 stiff and short straw-like setae lining margin, some of these paired with long setae or occasionally short setae paired together, setal formula of article 4 of pereopods 1-2 = 3 and 3, of article 5 = 1 and (0 or rudimentary), article 6 with rows of 3 and 3 spines, anterior margin of article 2 on pereopods 1-2 with up to 18 straw-like setae. Coxa 5 slightly smaller and coxa 6 much smaller than in female; posteroventral setule formula on coxae 5-7 = l-2-(3^i). Article 6 of pereopods 3-4 more elongate than in female, articles 4-5 narrower, article 2 of pereopod 4 narrower, spine densities much lower; pereopod 5 relatively more elongate and/or thinner than in female, dactyl reduced, anterior margins of article 2 on pereopods 3-5 with dense fuzz composed of stiff, straw-like setules, article 2 of pereopod 4 with only short anterior ridge. Epimera elongate anteroposteriorly, epimeron 1 without distinct ridge (illustration showing 2 artificial folds), with one anteroventral seta and posterior face with vertical row of 2-3 setae, posterior margin strongly bulbous, strawlike setae absent; epimeron 2 with bulbous posterior margin, no lateral ridge, or remnant of ridge, row of 6 setae in weak crescent or 3 horizontal and one highly disjunct seta or in groups of 2-1-1; epimeron 3 with 2 or 3 facial setae set highly ventrad. Basofacial rudimentary setae of uropod 1 somewhat more distinct than in female, outer ramus with 3-4 dorsal spines, inner with one; peduncle of uropod 2 with 3-6 spines, apicomedial corner with only pair of setules, outer ramus with 2 spines, inner ramus of uropod 2 with basomedial spine. Uropod 3 similar to that of terminal female but lacking ventral peduncular spines, dorsally with one lateral, one medial setule; rami of proportions similar to terminal female, inner more strongly setose, spines on acclivities of outer ramus converted to setae, setal formula = 2-2-2-2-2. Telson less cleft than in female, main apical spine on each lobe very short, each lobe with mediodorsal row of denticles.

 

Description of juvenile (juvenile “u,” 2.65 mm)—Generally similar to adult female, but eyes very small; flagella of antenna 1 with 11 primary and 9 accessory articles; spine formula of article 4 on antenna 2 = 1-3-7, article 5 with 4 facial spines; epimeron 1 with one long anteroventral seta, 4 straw-like anterior setules, 2 posterofacial setae (vertical row), epimeron 2 with 3 facial setae (2 horizontal, one thrust), epimeron 3 with 3 setae; uropod 1 peduncle with one spine, outer and inner rami each with one dorsal spine, peduncle of uropod 2 with 4-5 spines, outer ramus with one, inner lacking dorsal spines; uropod 3 with short inner ramus (as illustrated for large female "n").

 

Variations—Female holotype with straw-like setae poorly developed in comparison with other specimens; other females usually of larger body size but female holotype generally with most advanced morphology except in regard to straw-like setae of epimeron 1. Specimens bearing glue-like exudates creating great difficulty in dissecting and mounting parts. Large female "n," 4.20 mm, with juvenoid uropod 3 bearing short inner ramus (see illustration).

 

Illustrations—Female: Antenna 1 drawn from medial aspect but description based on observed lateral aspect (as usual); outer lobule of article 2 on antenna 2 not adequately illustrated, poorly preserved or often glued to article 3 by preservational exudate; lower lip of female "n" bearing offset flattened outer lobe; coxae in poor condition, illustrations representing reconstructions; dactyl of maxilliped bearing outer basal short pluseta hidden by other structures; illustration of left pereopod 1 of holotype showing dotted seta on article 5, this seta represented on right pereopod 1 but formed as short spine on left pereopod 1 as shown.

 

Male: Sketch of head in Figure 68: vCn with antenna 2 removed to show mandible (shaded), remainder of structure being prebuccal complex (note horizontal position of this structure); pereopod 3 drawn about 3 percent smaller than pereopod 5, pereopod 4 drawn about 10 percent smaller than pereopod 5; pereopods 3-5 larger relative to body than in female.

 

Holotype—NMV, female "a," 3.46 mm.

 

Type-locality—CPBS 32/E2, 19 Feb 1965, Western Port, Victoria, Australia, 12.8 m, sand.

 

Voucher material—Type-locality: female "b," 3.34 mm. RHM: male "v," 3.55 mm (illus.); male "y," 3.60 mm <illus.). CPBS 51N: female "w," 4.0 mm (in 2 pieces, illus). PPBES 979/1: female "n," 4.20 mm (illus.); juvenile "u," 2.65 mm.

 

Material—CPBS, 8 samples from 5 stations (11); RHM, 2 samples from 2 stations (4); PPBES, 3 samples from 2 stations (4); WPBES, 2 samples from 2 stations (3).

 

Distribution—Victoria: Western Port and Port Phillip Bay, neritic and 12.0-16.5 m, sand, muddy sand.”

 

 

(Barnard & Drummond, 1978: 167-174)

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Creative Commons Attribution Non Commercial 3.0 (CC BY-NC 3.0)

© National Museum of Natural History, Smithsonian Institution

Source: Antarctic Invertebrates Website (NMNH)

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