Typhlotanais priscilae, Segadilha & Serejo, 2022

Segadilha, Juliana L. & Serejo, Cristiana S., 2022, New insights gained from museum collections: new deep-sea species of Typhlotanais (Tanaidacea, Typhlotanaidae) from Brazil, European Journal of Taxonomy 820, pp. 1-54 : 35-41

Typhlotanais priscilae sp. nov.

urn:lsid:zoobank.org:act:373A54F6-39DF-4AE4-BB1A-5C18E8D82EBD

Figs. 14–16 , 21

Diagnosis

Body 5.0 × L:W; cephalothorax rounded; antenna article-3 with long seta reaching half-length of article-4; pereopod-1 carpus with two distal long setae (one dorsal and one ventral); pereopods 2–3 ischium with stout seta as long as merus distal margin; propodus with ventrodistal seta; dactylus with seta twice as long as unguis; pereopods 4–6 propodus seta longer than dactylus and unguis combined; uropod stout, 0.9× as long as pleotelson; exopod one-articled, 0.9× as long as endopod; endopod onearticled, 3.0× L:W.

Etymology

Named in honour of MSc. Priscila Soares do Nascimento (Museu Nacional/UFRJ) in recognition of her friendship, collaboration, and great enthusiasm during many years at the Carcinology Lab of Museu Nacional/UFRJ.

Material examined

Holotype

BRAZIL – Espírito Santo State • ♀ ovigerous, length 1.2 mm; Espírito Santo Basin ; stn AMB 8 E7 R 1; 19.7850° S, 39.0533° W; depth 1258 m; 28 Jan. 2012; MZUSP 38972 .

Paratypes

BRAZIL – Rio de Janeiro State • 1 neuter (dissected), length 1.2 mm; Campos Basin , stn HAB 3 C8 R1; 23.0257° S, 40.7565° W; depth 975 m; 10 May 2008; MZUSP 38017 . – Espírito Santo State • 1 neuter; Espírito Santo Basin , stn AMB 6 CAMWN 6 R1 ; 19.8914° S, 39.5487° W; depth 1023 m; 13 Jan. 2012; MZUSP 38962 .

Additional material (lost in the fire)

BRAZIL – Rio de Janeiro State • 2 neuters; Campos Basin , HAB 3 C8 R3 ; 23.0257° S, 40.7565° W; depth 975 m; 10 May 2008; MZUSP 22907 • 1 neuter; Campos Basin , stn HAB 3 B8 R 2; 23.2298° S, 40.9323° W; depth 986.4 m; 8 May 2008; MZUSP 32867 • 1 neuter; Campos Basin , stn HAB 3 B8 ; 23.2298° S, 40.9323° W; depth 986.4 m; 8 May 2008; MZUSP 34436 .

Description

Paratype (MZUSP 38009 dissected)

MEASUREMENTS. Length 1.2 mm. Body ( Fig. 14A–B ) slender, 5.1 × L:W. Cephalothorax rounded 1.1× L:W, 1.1× as long as pereonite-1, naked; eyes absent. PEREONITES 1–6. All pereonites rectangular, longer than wide, with lateral margins gently convex; pereonite-1 shortest, 0.3 × L:W, with minute seta on proximal margin; pereonite-2 0.5× L:W; pereonite-3 0.4 × L:W; pereonite-4 0.6× L:W, with two minute setae on lateral margin; pereonite-5 0.7× L:W, with minute seta on lateral margin; pereonite-6 0.5× L:W.

PLEON ( Fig. 14A–B ) 0.3× TBL, with five subequal pleonites, together longer than carapace and pereonite-1 combined. Pleotelson trapezoidal 0.6× L:W, with a pair of terminal spines and three pairs of setae distally.

ANTENNULE ( Fig. 14C ). As long as cephalothorax, with three articles; article-1 0.6× TL, 2.3× L:W, with rod and seven penicillate middle setae, and with rod and four penicillate distal setae; article-2 0.8× L:W, 0.3 × as long as article-1, with two rod and penicillate distal setae; article-3 3.7× L:W, 2.3 × as long as article-2, with six rod and penicillate terminal setae.

ANTENNA ( Fig. 14D ) of six articles, article-1 lost during dissection; article-2 broken during dissection, with rod seta; article-3 0.9× L:W, with long penicillate seta (reaching half length of article-4); article-4 3.8× L:W, 3.8× as long as article-3, with strong microtrichia on outer margin, two stout rod and two penicillate distal setae; article-5 2.9× L:W, 0.5 × as long as article-4, with distal rod seta; article-6 minute with five rod terminal setae.

LABRUM ( Fig. 15A ). Rounded, hood-shaped, distally covered by minute setae. Mandible ( Fig. 15B–C ) molar broad well-developed with many prominent nodules. Left mandible ( Fig. 15B ) incisor simple, lacinia mobilis well developed, with four lobes; right mandible ( Fig. 15C ) incisor distally truncated gently undulated, without lacinia mobilis. Labium ( Fig. 15D ) with distolateral corner finely setose; outer lobe membranous. Maxillule ( Fig. 15E ) endite with eight terminal spines (one short); palp with two distal stout setae. Maxilla ( Fig. 15F ) triangular. Epignath ( Fig. 15G ) elongate, linguiform, naked. Maxilliped ( Fig. 15H ) sparsely setose; basis with simple as long as distal margin of endites; endites with two large gustatory cusps and seta on distal edge and microtrichia on outer corner; palp with four articles; article-1 triangular, naked; article-2 with three inner setae (one simple, one rod and one serrated) and seta on outer margin; article-3 with three serrated and one simple inner setae; article-4 with five serrated inner setae and subdistal outer seta.

CHELIPED ( Fig. 15I ). Slender, basis elongate, distally rounded, 2.6× L:W, with dorsodistal seta; merus subtriangular, with ventral seta; carpus 2.1× L:W, with two ventral setae; propodus 1.1× as long as carpus, 2.6× L:W, with two setae near dactylus insertion (one on inner and one on outer side); fixed finger with two rod ventral setae; cutting edge almost simple, with small subdistal protrusion and three rod setae; dactylus as long as fixed finger.

PEREOPOD-1 ( Fig. 16A ). Walking type, with strong microtrichia; slender, longer than others; coxa with seta; basis elongate 4.6× L:W, naked; ischium with ventral stout seta; merus 1.6 × L:W, with dorsodistal rod and ventrodistal simple setae; carpus 1.7 × L:W, slightly longer than merus, with two dorsodistal (one long and one short) and two ventrodistal setae (one long and one short); propodus 2.6× L:W, 1.1× as long as carpus, with three stout dorsodistal and one ventrodistal setae; dactylus 1.2 × as long as unguis, with seta as long as unguis; dactylus and unguis together 0.8× as long as propodus.

PEREOPOD-2 ( Fig. 16B ). Walking type, with strong microtrichia; coxa with seta; basis 3.6 × L:W, naked; ischium with ventral stout seta (as long as merus distal margin); merus about as long as wide, with dorsodistal and ventrodistal setae; carpus 0.8× L:W, with dorsodistal seta and ventrodistal robust spine; propodus 1.9× L:W, 0.7× as long as merus and carpus combined, with two dorsodistal (one slightly serrated and one rod) and ventrodistal simple setae; dactylus 1.2 × as long as unguis, with long seta twice as long as unguis (broken during dissection); dactylus and unguis together 0.9 × as long as propodus.

PEREOPOD-3 ( Fig. 16C ). Similar to pereopod-2, except basis 2.7× L:W, with ventral rod seta; merus with one ventrodistal seta; carpus 1.1 × L:W; propodus 2.4 × L:W.

PEREOPOD-4 ( Fig. 16D ). Clinging type, with strong microtrichia; coxa absent; basis robust 1.3× L:W, with two long penicillate ventral setae; ischium with seta; merus triangular about 2.2× L:W, with two ventrodistal spines (only one illustrated); carpus 1.5× L:W, with dorsodistal spine and prickly tubercles about as long as half carpus; propodus 3.1 × L:W, with slightly serrated dorsodistal seta longer than unguis and two ventrodistal spines (only one illustrated); dactylus 3.2 × as long as unguis, both combined 0.9 × as long as propodus.

PEREOPOD-5 ( Fig. 16E ) similar to pereopod-4, except basis 1.7× L:W, naked; propodus with penicillate middorsal seta.

PEREOPOD-6 ( Fig. 16F ). Similar to pereopod-4, except basis twice L:W, with penicillate dorsal seta; propodus with three slightly serrated dorsodistal setae (one longer than and two as long as unguis).

PLEOPOD ( Fig. 16G ). All pleopods similar; basal article naked; exopod with seven plumose setae on outer margin and with plumose seta on inner margin; endopod with twelve plumose setae on outer margin; gap between proximal seta and others in both rami.

UROPOD ( Fig. 16H ). Stout, 0.9× as long as pleotelson; basis 0.8× L:W, naked; exopod one-articled, 4.4× L:W, 0.9 × as long as endopod, with simple medial seta, one stout and one minute setae distally; endopod one-articled; 3.3 × L:W, with subdistal stout seta, two rod, two simple and two penicillate setae distally.

Distribution

Brazil: Campos Basin, Rio de Janeiro and Espírito Santo Basin, Espírito Santo. Occurring on the middle slope, depth range from 975 to 1258 m ( Fig. 21 ).

Remarks

Typhlotanais priscilae sp. nov. is part of the ‘ spinicauda ’ group by the presence of two strong spines on distal margin of pleotelson ( Table 4 ). The new species can be distinguished from both T. spinicauda and T. squamiger by its (1) body stout, 5.0 × L:W ( T. spinicauda 7.5× L:W and T. squamiger 8.3 × L:W); (2) antenna article-3 with long seta reaching half length of article-4; (3) pereopod-1 carpus with two long setae; (4) pereopods 1–3 ischium with long seta; (5) pereopods 2–3 propodus with ventrodistal seta (instead of spine); (6) pereopods 2–3 dactylus with seta twice as long as unguis; (7) pereopods 4–6 propodus seta longer than unguis; (8) uropod stout, 0.9× as long as pleotelson; (9) uropod exopod onearticled, 0.9× as long as endopod; (10) uropod endopod one-articled, 3.0× L:W.

“ trispinosus ” group

Species included

Typhlotanais spatulasetosus Larsen, 2012 ; T. tenuicornis Sars, 1882 ; T. trispinosus Hansen, 1913 ; T. spinibasis sp. nov.

Figures

Fig. 14. Typhlotanais priscilae sp. nov., ♀, dissected (MZUSP 38009). A. Dorsal view. B. Lateral view. C. Antennule. D. Antenna. Scale bars: A–B = 1 mm; C–D = 0.1 mm.

Fig. 15. Typhlotanais priscilae sp. nov., ♀, dissected (MZUSP 38009). A. Labrum. B. Left mandible. C. Right mandible. D. Labium. E. Maxillule. F. Maxilla. G. Epignath. H. Maxilliped. I. Cheliped. Scale bar = 0.1 mm.

Fig. 16. Typhlotanais priscilae sp. nov., ♀, dissected (MZUSP 38009). A–F. Pereopods 1–6.G. Pleopod. H. Uropod. Scale bar = 0.1 mm.

Fig. 21. Bathymetric range of species of Typhlotanais along the Brazilian coast (19° S–24° S) based on samples listed in Table 1.