Torbenella lupi Macpherson & Rodríguez-Flores & Machordom 2023, sp. nov.

Torbenella lupi sp. nov.

urn:lsid:zoobank.org:act: FE41E3F0-3236-4B3D-AB95-CC190C43A233

Fig. 4

Torbenella aff. orbis 1. — Machordom et al. 2022: table 2.

Etymology

The name ‘ lupi ’ refers to one of the southern hemisphere constellations (the Wolf).

Material examined

Holotype PAPUA-NEW GUINEA • ov. ♀ (10.2 mm); KAVIENG stn CP4418; 02º27′ S, 150º40′ E; 335–340 m depth; 28 Aug. 2014; GenBank no.: COI: OP215693, 18S: OP196289, PEPCK: OP252566; MNHNIU-2014-10024.

Paratypes PAPUA-NEW GUINEA • 3 ♂♂ (6.5–8.0 mm), 3 ov. ♀ (7.5–8.0 mm), 1 ♀ (5.9 mm); KAVIENG stn DW4495; 02º24′ S, 149º55′ E; 272–274 m depth; 6 Sep. 2014; MNHN-IU-2014-9900 • 1♀ (7.2 mm); KAVIENG stn CP4496; 02º25′ S, 149º54′ E; 269–274 m depth; 6 Sep. 2014; MNHN-IU-2014-13983.

Description

CARAPACE. Slightly wider than long. Transverse ridges usually interrupted, except several on gastric region and posterior part of carapace, with dense very short setae. Main transverse striae on posterior part of carapace interrupted in cardiac region. Scales and secondary striae absent between main striae. Gastric region with 2 main epigastric spines each behind supraocular spine; with row of 4–5 minute flanking spines and some small spines at base of rostrum and in parahepatic, hepatic and anterior branchial regions; one small postcervical spine on each side. Orbit with lateral limit weakly defined. Frontal margins concave. Lateral margins slightly convex. Anterolateral spine well developed, at anterolateral angle, reaching level of sinus between rostrum and supraocular spines. One or 2 very small marginal spines anterior to cervical groove. Branchial margins with 4 (rarely 5) small spines. Rostrum spiniform, less than half as long as remaining carapace, not exceeding end of corneae, carinated dorsally, straight, and directed slightly upwards. Supraocular spines barely reaching midlength of rostral spine and falling short of end of corneae, subparallel, directed slightly upwards.

THORACIC STERNUM. Smooth, without striae, except a few on sternite 4. Sternite 3 2.5 times as wide as long; sternite 4 2.8 times as wide as long, and 2.3 times as wide as sternite 3. Anterior part of sternite 4 slightly narrower than sternite 3; anterior margin widely contiguous to sternite 3.

ABDOMEN. Somites 2–4 with 2 median spines on anterior ridge; posterior ridge of somite 4 with small median spine. Somites 2–3 each with 3 transverse ridges and several scales in addition to anterior ridge. Somite 4 with a few striae.

EYES. Eyes large, maximum corneal diameter 0.4 times distance between bases of anterolateral spines.

ANTENNULE. Article 1 (distal spines excluded) about one-third carapace length, elongate, barely reaching end of corneae, with 2 short distal spines, mesial spine shorter than lateral spine; lateral margin unarmed, bearing numerous long plumose setae.

ANTENNA. Article 1 with prolonged, strong mesial process exceeding antennular peduncle, lateral border with numerous long plumose setae; article 2 with 2 distal spines, distomesial longer than distolateral, barely reaching end of article 3; article 3 with distomesial spine, article 4 unarmed.

MXP3. Ischium about 1.5 times length of merus, distoventrally produced to spine. Merus with welldeveloped median spine on flexor margin, extensor margin unarmed.

P1. 2.5–3 times carapace length, squamous, with dense short setae on scales, with scattered long setae. Merus 1.3–1.5 times carpus length, armed with some mesial spines, distalmost strongest. Carpus slightly longer than palm, 3 times as long as wide, with several spines along mesial margin. Palm slightly longer

than fingers, with few small spines on mesial border. Fingers unarmed, distally curving and crossing, ending in sharp point.

P2–4. Moderately long and slender, squamous, with dense short setae on scales, with some long iridescent setae along extensor margins of all articles. P2 twice carapace length. Meri successively shorter posteriorly (P3 merus 0.8 times length of P2 merus, P4 merus 0.8 times length of P3 merus); P2 merus 0.8 times carapace length, 4.5–5.0 times as long as wide, 1.7 times as long as P2 propodus; P3 merus 4.0–4.5 times as long as wide, 1.5 times as long as P3 propodus; P4 merus 3.5–4.0 times as long as wide, 1.3 times as long as P4 propodus. Extensor margins of meri with row of small, proximally diminishing spines on P2–3, distal spine only on P4; flexor margins with distal spines followed proximally by several eminences; lateral sides unarmed. Carpi with several spines on extensor margin; flexor margin ending in blunt point. Propodi 4.0–4.5 times as long as wide; extensor margin unarmed; flexor margin with 4–5 slender movable spines, without fixed distal spine. Dactyli slender, length 0.9 times that of propodi; flexor margin with 2 median movable spinules; P2 dactylus 5.5 times as long as wide.

Genetic data

Partial genes of COI, 18S and PEPCK were successfully sequenced. As usual, the COI sequence showed the highest levels of divergence, 4.86% comparing T. aequabilis sp. nov. and T. orbis, and 15.42% to T. calvata. Torbenella lupi sp. nov. formed a well-supported cluster (pp = 1) with T. aequabilis and T. orbis (Fig. 7).

Remarks

The new species is morphologically closely related to T. orbis (Baba, 2005) and T. mensae sp. nov., sharing the presence of median spines on the anterior ridge of the abdominal somite 2. Characters distinguishing the three species are outlined under the Remarks of T. mensae (see below).

Distribution

Papua-New Guinea, between depths of 269 and 340 m.