Typhlotanais andradeorum, 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 : 9-15

Typhlotanais andradeorum sp. nov.

urn:lsid:zoobank.org:act:02865676-2AB5-4DA7-AC67-1F11317DA7F8

Figs 2–4 , 21

Diagnosis

Carapace elongate, 1.5× L:W; antenna, mandibles and maxillule densely covered with microtrichia; maxilliped endites with two very large gustatory cusps (covering almost the entire distal margin of the endites); cheliped fixed finger with two rod setae ventrally and two rod (one long and one short) and one simple setae on cutting edge; pereopod-1 merus elongate (2.6× L:W); pereopods 2–3 coxae with very long setae reaching half-length of basis; pereopods 4–5 propodus dorsodistal seta shorter than dactylus and unguis combined; pereopod-6 propodus with three dorsodistal setae (one longer and two shorter than dactylus and unguis combined); and uropod with both rami two-articled, exopod about half length of endopod.

Etymology

This species is dedicated to first author’s parents from the family name Andrade, in recognition of their ever-lasting support and love. Gender of specific name: masculine.

Material examined

Holotype

BRAZIL – Rio de Janeiro State • neuter, length 1.2 mm; Campos Basin , stn HAB 8 B9 R1 ; 23.2532° S, 40.8981° W; depth 1228.5 m; 14 Jan. 2009; MZUSP 38967 .

Paratypes

BRAZIL – Rio de Janeiro State • 3 neuters (1 dissected), length 1.3 mm; Campos Basin , stn HAB 3 B9 R3 ; 23.2520° S, 40.8982° W; depth 1302.3 m; 9 May 2008; MZUSP 32839 • 1 neuter; Campos Basin , stn HAB 3 B8 R2 ; 23.2298° S, 40.9323° W; depth 986.4 m; 8 May 2008; MZUSP 34415 . – Espírito Santo State • 1 neuter; Espírito Santo Basin , stn AMB 5 B7 R2 ; 21.0793° S, 40.0752° W; depth 1294 m; 31 Dec. 2011; MZUSP 38978 .

Additional material (lost in the fire)

BRAZIL – Rio de Janeiro State • 2 neuters; Campos Basin , stn HAB 4 CANG 8 R3 ; 21.9175° S, 39.9102° W; depth 1002.4 m; 28 May 2008; MZUSP 32845 • 1 neuter; Campos Basin , stn HAB 4 G9 R3 ; 22.1214° S, 39.8177° W; depth 1299.8 m; 28 May 2008; MZUSP 32846 • 2 neuters; Campos Basin , stn HAB 3 C8 R1 ; 23.0257S, 40.756° W; depth 975 m; 10 May 2008; MZUSP 32849 • 4 neuters; Campos Basin , stn HAB 4 CANG 8 R3 ; 21.9175° S, 39.9102° W; depth 1002.4 m; 28 May 2008; MZUSP 32853 • 2 neuters; Campos Basin , stn HAB 4 F9 R3 ; 22.4289° S, 39.901° W; depth 1288.5 m; 29 May 2008; MZUSP 32855 • 2 neuters; Campos Basin , stn HAB 4 CANG 8 R3 ; 21.9175° S, 39.9102° W; depth 1002.4 m; 28 May 2008; MZUSP 32864 • 1 neuter; Campos Basin , stn HAB 6 CANAC 8 ; 21.7638° S, 39.9924° W; depth 1035 m; 27 Jun. 2008; MZUSP 34413 • 1 neuter; Campos Basin , stn HAB 4 A11 ; 24.0219° S, 40.9043° W; depth 2486 m; 18 May 2008; MZUSP 34421 • 1 neuter; Campos Basin , stn HAB 3 H9 ; 21.6555° S, 39.8993° W; depth 1293.2 m; 13 May 2008; MZUSP 34437 • 1 neuter, 1 juvenile; Campos Basin , stn HAB 4 G9 R3 ; 22.1214° S, 39.8177° W; depth 1299.8 m; 28 May 2008; MZUSP 42600 • 1 neuter; Campos Basin , stn HAB 9 H8 R3 ; 21.6713° S, 39.9684° W; depth 1005.8 m; 6 Feb. 2009; MZUSP 38010 • 1 neuter; Campos Basin , stn HAB 9 CANAC 7 R2 ; 21.7907° S, 40.0320° W; depth 780 m; 6 Feb. 2009; MZUSP 38011 • 1 neuter; Campos Basin , stn AC #32 ; 22.6319° S, 40.2920° W; depth 900 m; 18 May 2002; MNRJ 18207 • 1 neuter; Campos Basin , stn AC #19 ; 22.0828° S, 39.8351° W; depth 1230 m; 9 May 2002; MNRJ 18255 • 1 neuter; Campos Basin , stn AC #22 ; 22.0795° S, 39.8192° W; depth 1350 m; 9 May 2002; MNRJ 18276 • 1 neuter; Campos Basin , stn AC #23 ; 22.0417° S, 39.8281° W; depth 1350 m; 8 May 2002; MNRJ 18287 • 1 neuter; Campos Basin , stn OP #46 ; 22.1821° S, 39.8168° W; depth 1350 m; 10 Dec. 2002; MNRJ 20484 • 1 neuter; Campos Basin , stn OP #78G ; 22.6175° S, 39.9389° W; depth 1950 m; 13 Jun. 2003; MNRJ 20678 • 1 neuter; Campos Basin , stn OP #71 ; 22.6480° S, 40.0712° W; depth 1350 m; 14 Jun. 2003; MNRJ 20706 • 1 neuter; Campos Basin , stn OP #76 ; 22.5681° S, 40.0035° W; depth 1350 m; 15 Jun. 2003; MNRJ 20686 • 1 neuter; Campos Basin , stn OP #56 ; 21.9543° S, 39.8271° W; depth 1350 m; 14 Dec. 2002; MNRJ 27355 . – Espírito Santo State • 1 neuter; Espírito Santo Basin , stn AMB 11 C6 R1 ; 20.2598° S, 39.7713° W; depth 1040 m; 9 Jan. 2012; MZUSP 37682 .

Description

Paratypes (MNRJ 18207; MZUSP 32839 dissected)

BODY ( Fig. 2A–B ). Slender, 6.4 × L:W. Cephalothorax elongate 1.5× L:W, 3.2× as long as pereonite-1, naked; eyes absent.

PEREONITES 1–6. All pereonites rectangular, wider than long, with lateral margins gently convex; pereonite-1 shortest, 0.4× L:W, with short seta on proximal margin; pereonite-2 0.6× L:W; pereonite-3 0.6× L:W; pereonite-4 0.7 × L:W, with minute seta on lateral margin; pereonite-5 0.7× L:W, with two minute setae on lateral margin; pereonite-6 0.6× L:W, with three minute setae on lateral margin.

PLEON ( Fig. 2A–B ). 0.25 × TBL, with five subequal pleonites, together about as long as carapace and pereonite-1 combined; last pleonite with minute seta on lateral margin. Pleotelson trapezoidal 0.6 × L:W, with seta on lateral margin and three pairs of setae distally.

ANTENNULE ( Fig. 2C ). 0.7× as long as cephalothorax, with three articles; article-1 0.6 × TL, 2.5× L:W, with two simple and four penicillate middle setae, and one simple and three penicillate setae distally; article-2 1.2× L:W, 0.2 × as long as article-1, with two simple and one penicillate distal setae; article-3 3.2× L:W, 2.0× as long as article-2, with aestethasc, five simple and one penicillate terminal setae.

ANTENNA ( Fig. 2D ). With six articles, article-1 with microtrichia, fused with body; article-2 1.2× L:W, with microtrichia; article-3 0.9× L:W, with microtrichia; article-4 4.0× L:W, 2.7× as long as article-3, with microtrichia and two simple and three penicillate setae distally; article-5 2.8× L:W, 0.4 × as long as article-4, with distal seta; article-6 minute with six simple terminal setae.

LABRUM ( Fig. 3A ). Rounded, hood-shaped, covered by minute setae. Mandible ( Fig. 3B–C ) molar broad with many prominent nodules, which are small and regular on one side and large and irregular on the other. Left mandible ( Fig. 3B ) with microtrichia on outer margin, incisor smooth, lacinia mobilis well developed, with four lobes; right mandible ( Fig. 3C ) as left, but without lacinia mobilis. Maxillule ( Fig. 3D ) endite with seven to eight terminal spines; palp broken off during dissection. Labium ( Fig. 3E ) with distal corner finely setose; outer lobe membranous and finely setose on outer margins. Maxilliped ( Fig. 3F ) sparsely setose; basis with simple seta not reaching distal margin of endites; endites unfused, with long medial seta, two very large gustatory cusps (covering almost all distal margin of the endites) and short seta on distal edge and microtrichia on outer corner; palp with four articles; article-1 naked; article-2 with three inner setae (one simple and two serrated) and minute seta on outer margin; article-3 with three serrated inner setae; article-4 with five serrated inner setae and one simple subdistal outer seta. Maxilla not observed. Epignath not observed.

CHELIPED ( Fig. 3G ) basis not reaching pereonite-1, distally rounded, with microtrichia; 2.1× L:W; merus subtriangular, with ventral seta; carpus stout 1.9× L:W, with three ventral setae and microtrichia; propodus 1.8 × 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 setae ventrally; cutting edge with two rod (one long and one short) and one simple setae; dactylus as long as fixed finger.

PEREOPOD-1 ( Fig. 4A ). Walking type, slender; coxa with seta; basis elongate 3.5 × L:W, with penicillate dorsal seta; ischium with seta; merus elongate 2.6× L:W, with ventrodistal seta and microtrichia; carpus 1.7 × L:W, 0.6× as long as merus, with two dorsodistal setae and seta and spine ventrodistally; propodus 3.2 × L:W, 1.4 × as long as carpus, with two spines and seta dorsodistally; dactylus 0.6× as long as unguis; unguis with tip enlarged (not thin); dactylus and unguis together 0.8× as long as propodus.

PEREOPOD-2 ( Fig. 4B ). Walking type; coxa with long seta (longer than half length of basis); basis 3.5× L:W, with penicillate dorsal seta; ischium with seta; merus about 1.4× L:W, with two ventrodistal setae; carpus 1.6 × L:W, with two dorsodistal and one long ventrodistal setae (longer than half length of propodus); propodus 2.6× L:W, 0.7× as long as merus and carpus combined, with two dorsodistal setae and microtrichia; dactylus twice as long as unguis, with seta shorter than unguis; dactylus and unguis together 0.6× as long as propodus.

PEREOPOD-3 ( Fig. 4C ). As pereopod-2.

PEREOPOD-4 ( Fig. 4D ). Clinging type; coxa absent; basis robust 2.4 × L:W, with penicillate and simple setae ventrally; ischium with seta; merus triangular 1.4× L:W, with two ventrodistal spines and microtrichia; carpus 1.6 × L:W, with strong distal spur and simple dorsodistal seta and prickly tubercles about as long as half length of carpus; propodus about 3.8× L:W, with robust dorsodistal seta longer than unguis, two ventrodistal spines and microtrichia; dactylus 1.9× as long as unguis, both combined as long as propodus.

PEREOPOD-5 ( Fig. 4E ). Similar to pereopod-4, except propodus about 1.8× L:W.

PEREOPOD-6 ( Fig. 4F ). Similar to pereopod-5, except basis twice L:W, with simple ventral seta; propodus with three robust dorsodistal setae (one longer and two shorter than unguis).

PLEOPOD ( Fig. 4G ). All pleopods similar; basal article naked; exopod with eight plumose setae on outer margin and with plumose seta on inner margin; endopod with 14 plumose setae on outer margin. Large gap between proximal seta and others in both rami.

UROPOD ( Fig. 4H ). As long as pleotelson; basis 0.8× L:W, naked; exopod two-articled, 0.6× as long as endopod, with simple medial seta and tipped by stout and simple setae; endopod two-articled; 5.5× L:W, with one simple and two penicillate medial setae, simple seta subdistally, tipped by four simple and two penicillate setae.

Distribution

Brazil: Campos Basin, Rio de Janeiro and Espírito Santo Basin, Espírito Santo. Occurring on the lower slope and the São Paulo plateau area, from the depth range 780 to 2500 m ( Fig. 21 ).

Remarks

Typhlotanais andradeorum sp. nov. is characterized by three diagnostic characters as pereopods 2–3 coxae with very long setae reaching half-length of basis, cheliped fixed finger with two rod (one long and one short) plus one simple setae on cutting edge and the mandible outer margin covered with several microtrichia. This last character is unique and is not seen in any of other species of Typhlotanais . Futhermore, T. andradeorum sp. nov. shows both rami of uropod two-articled, characters shared with Typhlotanais species as T. messinensis Sars, 1882 , T. mimosis Błażewicz-Paszkowycz, 2007 , T. mixtus Hansen, 1913 , T. spinicauda Hansen, 1913 , T. squamiger Błażewicz-Paszkowycz, 2007 and T. andeepae Błażewicz-Paszkowycz, 2007 . However the new species can be immediately distinguished by: (1) pereopods 2–3 coxae with very long setae (half-length of basis); and (2) cheliped fixed finger with two rod and one simple setae on cutting edge (which the second rod seta is shorter than the first and also than the simple seta).

Figures

Fig. 2. Typhlotanais andradeorum sp. nov. A. ♀ (MNRJ 18207), dorsal view. B–D. Paratype (MZUSP 32839), ♀, dissected. B. Lateral view.C. Antennule.D. Antenna. Scale bars:A–B = 1 mm; C–D = 0.1 mm.

Fig. 3. Typhlotanais andradeorum sp. nov., paratype (MZUSP 32839), ♀, dissected. A. Labrum. B. Left mandible. C. Right mandible. D. Maxillule. E. Labium. F. Maxilliped. G. Cheliped. Scale bar = 0.1 mm.

Fig. 4. Typhlotanais andradeorum sp. nov., paratype (MZUSP 32839), ♀, dissected. 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.