Coriollianassa mainbazae, Poore, 2023

Poore, Gary C. B., 2023, New records, one new genus and 21 new species of Callianassidae (Crustacea, Axiidea) from the Indo-West Pacific, Memoirs of Museum Victoria 82, pp. 167-255 : 188-191

Coriollianassa mainbazae sp. nov.

http://zoobank.org/urn:lsid:zoobank.org:act:E1B2D755-3C57-

4036-84C1-01C4C7BB5DC7

Figures 16 , 17

Trypaea sibogae .— Sakai and Türkay, 2012: 738–740, fig. 7 (Gulf of Aden).

Coriollianassa MOZ-33.— Poore et al., 2019: fig. 8c.— Robles et al., 2020: figs 1, 3, 6.

Material examined. Holotype. Mozambique, off Maputo, 25° 59' S, 34° 35' E, 630–638 m (MAINBAZA stn CC3173 ), MNHN IU-2008- 10314 * (male, 8.0 mm) . Paratypes. Collected with holotype, MNHN IU-2008-10315 * (female, 7.7 mm). Mozambique , off Maputo, 25° 36' S, 33° 17' E, 437–445 m, (MAINBAZA stn CC3172 ); MNHN IU-2008-7922 * (female, 8.8 mm); MNHN IU-2016-8146 * (female, 6.3 mm). Off Bazaruto I., 21° 36'S, 35° 57'E, 990–996 m (MAINBAZA stn CC3147 ), MNHN IU-2010-7924 (female, 7.3 mm) .

Diagnosis. Rostrum with dorsal basal carina, with ventral straight keel-like carina. Maxilliped 3 merus with distinct oblique mesiodistal margin. Telson elongate-trapezoidal, 1.25 times as long as wide.

Description of male holotype. Rostrum laterally compressed, situated well below upper level of carapace, with dorsal basal carina, with ventral straight keel-like carina. Carapace convex anteriorly in lateral view, as long as pleomeres 1–3 combined; orbital margin concave; anterolateral angle produced slightly anteroventrally as narrow lobe; subanterolateral margin slightly convex, anterior margin of branchiostegite set well back, almost vertical; cervical groove across 0.75 length of carapace, almost reaching linea thalassinica. Pleomere 1 tergite waisted in dorsal view, with deep saddle visible in lateral view; posterior section flat in lateral view. Pleomere 2 widest, wider than long. Pleomeres 3–5 each wider than long; pleura each with patch of plumose setae. Pleomere 6 about as long as wide, 1.2 times as long as pleomere 5, with slight ventrolateral projection.

Eyestalk 1.2 times as long as wide, with oblique dorsal face diverging from rostrum, with sharp ventrolateral margin, anterolateral margin oblique, anteromedial angle rounded in dorsal view, not reaching distal margin of antennular peduncle article 1. Cornea with weak scattered pigmentation.

Antennular peduncle reaching to about distal margin of antennal peduncle article 4; article 1 clearly visible in dorsal view; article 2 shorter than article 1; article 3 1.4 times as long as articles 1 and 2 combined; articles 2 and 3 with longitudinal ventral row of sparse long setae. Antennal peduncle article 5 0.6 length of article 4; scaphocerite with bifid apex.

Mandible molar process shelf-like, with small mesial tooth; incisor process with obsolete teeth. Maxilliped 3 ischium tapering, twice as long as wide, crista dentata comprising row of about 18 strong, irregular, erect spines, stronger distally, overlapping distal margin; merus about 0.7 times as long as ischium measured along outer margin, about 1.4 times as wide as long, as wide as ischium, with distinct oblique mesiodistal margin; carpus shorter than merus; propodus ovoid, 1.7 times as long as wide; dactylus digitiform, 0.75 times as long as propodus.

Pereopods 1 (chelipeds) unequal, dissimilar. Male major cheliped massive, carpus-palm upper margin 1.1 times carapace length. Ischium expanding distally, upper margin sinuous, unarmed; lower margin with row of 7 spines. Merus as long as ischium, twice as long as wide (tooth excluded), tapering distally; upper margin convex, unarmed; lower margin with oblique spine bearing a subproximal minute tooth, plus row of small tubercles distal to spine. Carpus 1.3 times as long as wide, with constricted “neck”; margins carinate; upper margin smooth, concave over proximal third; lower margin convex, with distal sharp tooth. Propodus upper margin as long as carpus; palm subquadrate, 1.2 times as long as wide; upper margin carinate; lateral surface smooth, convex, with peg-like tooth in gape; mesial surface slightly convex, with peg-like tooth in gape set back from lateral peg; lower margin carinate, with row of setae extending onto fixed finger; fixed finger 0.8 times as long as palm, slightly depressed; cutting edge smooth, with obtuse blade at midpoint. Dactylus reaching as far as fixed finger, strongly curved distally, with acute tip; upper margin with tufts of long setae; lateral surface with few tufts of long setae along cutting edge; cutting edge with rounded teeth diminishing distally; mesial surface with tufts of setae along cutting edge.

Minor cheliped slender; carpus-palm upper margin 0.7 carapace length. Ischium upper margin smooth, lower margin with row of 5 spines. Merus about as long as ischium; lower margin with spine near midpoint. Carpus 1.4 times as long as merus, parallel-sided over most of length, 4 times as long as wide. Palm slightly swollen, 1.3 times as long as wide; upper margin convex; lower margin sharply carinate, with row of long setae extending onto fixed finger. Fixed finger about as long as palm, slightly curving down; cutting edge smooth. Dactylus 1.6 times as long as palm, curved; cutting edge smooth.

Pereopod 2 merus lower margin slightly sinusoidal, 3.0 times as long as wide; carpus about twice as long as wide; chela subtriangular; palm about twice as wide as upper margin; dactylus 3 times as long as palm upper margin. Pereopod 3 carpus subtriangular, 2.6 times as long as wide; propodus suboval with produced lower proximal margin, upper margin 1.4 times width, lower margin convex, faintly undulate, marginal setae clustered on prominences, with 1 slender spiniform seta subdistally; dactylus about 0.9 times as long as propodus upper margin. Pereopod 4 merus as long as ischium; carpus 0.8 length of merus; propodus 0.8 times as long as carpus, with dense grooming setae distally on lower margin, scattered stiff setae on outer surface, with spiniform seta parallel to dactylus; dactylus half as long as propodus. Pereopod 5 slender, with chela about as long as carpus, slightly curving; dactylus as long as fixed finger.

Male pleopod 1 uniarticulate, 8 times as long as wide, with few distal short setae. Pleopod 2 tubercle-like. Pleopods 3–5 biramous, rami narrow; appendix interna slender, rod-like, projecting well beyond mesial margin of endopod, bearing coupling hooks on apical margin.

Uropodal endopod and exopod overreaching posterior margin of telson. Endopod oval, about 1.6 times as long as wide; anterior margin slightly convex; anterodistal margin with 8 spiniform setae; distal margin convex, with fringe of setae; posterior margin with 3 stouter marginal setae; upper surface with row of up to 3 spiniform setae. Exopod dilating to rounded distal margin, 1.4 times as long as wide, exceeding endopod by about one fifth length; anterior margin convex, setose; posterior margin with numerous slender setae, with about 12 blade-like setae, indistinguishably merged with distal margin; upper surface with 1 or 2 submarginal slender setae about one third along; dorsal plate curved, short, about one third exopod width, with row of about 12 stiff setae distinct from setal row of distal margin.

Telson elongate-trapezoidal, 1.25 times as long as wide, broadest at anterior fifth, narrowing posteriorly; greatest width 1.7 times posterior width; dorsal surface with few medial setae anterior to midlength; lateral margin with 2 well-spaced spiniform setae near posterolateral angle; posterior margin convex, with median tooth.

Female. Major cheliped similar to male cheliped, carpus and palm more elongate; carpus 1.5 times as long as wide; propodus palm 1.4 times as long as wide. Minor cheliped similar to male. Pleopod 1 of 2 articles at right angles; ramus slightly longer than peduncle; setose (of single article in small female). Female pleopod 2 biramous; peduncle almost straight; exopod tapering distally, slightly shorter and narrower than endopod; endopod of 2 articles.

Etymology. For MAINBAZA, the survey of the coast of Mozambique in 2009 organised by the Instituto Español de Oceanografía and the Muséum national d’Histoire naturelle.

Distribution. Western Indian Ocean; 437– 996 m.

Remarks. Coriollianassa mainbazae has a longer and more tapering telson than other species of this genus. The rostrum is narrower and more acute in lateral view than in other species and is weakly carinate only on the carapace proper. Sakai and Türkay (2012) recorded and figured “ Trypaea sibogae ” from 472–479 m in the Gulf of Aden. The elongate pleomere 6 and telson plus geographic proximity suggest their record could be of C. mainbazae .

Figures

Figure 16. Coriollianassa mainbazae sp. nov. Mozambique. MNHN IU-2008-10314, holotype male, 8.0 mm: a, eyestalks, carapace, pleon, telson, right uropod; b, carapace, eyestalk, pleomeres 1, 2; c, d, anterior carapace, eyestalk, antennular, antennal peduncles (lateral, dorsal views); e, telson, right uropod;f, mandible;g, maxilliped 3; h–j, pleopods 1–3. MNHNIU-2008-7922, paratype female,8.8 mm:k, l, pleopods 1, 2. Scale bars = 1 mm.

Figure 17.Coriollianassa mainbazae sp. nov.Mozambique. MNHN IU-2008-10314, holotype male, 8.0 mm: a, major cheliped (left, mesial); b, minor cheliped (right, mesial); c–f, pereopods 2–5. MNHN IU-2008-7922, paratype female, 8.8 mm: g, major cheliped (right, mesial). Scale bar = 1 mm.