Dorsiceratus karinae, George & Tönjes & Yurtdaş, 2025

Dorsiceratus karinae sp. nov.

Figs 3 View Figure 3 , 4 View Figure 4 , 5 View Figure 5 , 6 View Figure 6 , 7 View Figure 7 , 8 View Figure 8 , 9 View Figure 9 , 10 View Figure 10 , 11 View Figure 11

Locus typicus.

northern plateau of the Eratosthenes Seamount, eastern Mediterranean Sea (33°47.13'N, 32°46.11'E, 906.0 m water depth), station #1100/1 -4   GoogleMaps , where # 1100 = station number, / 1 = no. of MUC deployment (= replicate), - 4 = no. of MUC - core.

Type material.

• Holotype: female, collected on 27. 12. 2009 at type locality, put on one slide, collection number SMF-37284/1 GoogleMaps ; • Paratype (PT) 1 (allotype): male, collected on 29. 12. 2009 at station #1112/8 -3 (33°37.47'N, 32°46.53'E, 874.4 m water depth), put on one slide, collection number SMF-37285/1 GoogleMaps ; • PT 2 : male, also collected at station #1112/8 -3 , put on one slide, collection number SMF-37286/1 ; • PT 3 : male, collected on 26. 12. 2009 at station #1095/7 -1 (33°38.11'N, 32°32.62'E, 942.6 m water depth), put on one slide, collection number SMF-37287/1 GoogleMaps ; • PT 4 : female, collected on 29. 12. 2009 at station #1095/6 -10 (33°38.11'N, 32°32.62'E, 942.5 m water depth), put on one slide, collection number SMF-37288/1 GoogleMaps ; • PT 5 : female, collected on 26. 12. 2009 at station #1112/7 -1 (33°37.48'N, 32°46.53'E, 874.7 m water depth), put on one slide, collection number SMF-37289/1 GoogleMaps ; • PT 6 : male, collected on 26. 12. 2009 at station #1095/7 -2 (33°38.11'N, 32°32.62'E, 942.5 m water depth), put on one slide, collection number SMF-37290/1 GoogleMaps ; • PT 7 : female, collected on 26. 12. 2009 at station #1095/6 -12 (33°38.11'N, 32°32.62'E, 942.5 m water depth), distributed on three slides, collection number SMF-37291/1 –3 GoogleMaps .

Etymology.

the epitheton karinae is given in fond dedication to LT’s mother, Mrs. Karin Tönjes (Apen, Germany). Gender: feminine.

Description of female.

Habitus (Fig. 3 A View Figure 3 ) slender and cylindrical, with inconspicuous boundary between pro- and urosome. Body length of holotype from rostral tip to end of FR 547 µm (mean 476 µm, range: 422–547 µm, n = 4), cphth and body somites dorsally with some sensilla and tube pores. Cphth and first three free thoracic somites dorsally with slender spinulose cuticular processes (CLDP, DT 1 – DT 3) that bear a sensillum at their tips and are accompanied by another sensillum at their bases. Rostrum as in the male (Fig. 11 A View Figure 11 ). Last thoracic and first abdominal somite fused into a GDS; former segmental demarcation still indicated by dorsal row of small spinules and pair of sensilla. Free thoracic body somites laterally with setular tufts, P 6 - bearing somite (= anterior half of GDS) additionally with tube pore. P 2 – P 6 - bearing somites dorsally also with 1 tube pore. First abdominal somite (= posterior half of GDS) and the following two abdominal somites dorsally with row of spinules at posterior margin; first and second abdominal somites additionally with pair of sensilla. Telson shorter than broad, slightly trapezoidal in shape from dorsal view. Anal operculum with some long spinules at its apical margin and basally flanked by a pair of sensilla.

FR (Fig. 3 B View Figure 3 ) cylindrical and slender, about four times longer than broad, with 6 setae: seta I completely lost; seta II arising at outer margin halfway along the ramus; seta III broken in all eight specimens, but insertion clearly discernible, with a short tube pore next to it; seta IV minute, arising apically at the outer edge; seta V longest, located apically; seta VI as small as IV, positioned apically at inner edge of the ramus; seta VII arising dorsally at the end of the ramus.

A 1 (Fig. 4 A View Figure 4 ) 4 - segmented, segments 1 and 3 of nearly the same length, second segment smaller, fourth segment about half the length of the third segment. First segment with row of long and flexible spinules at anterior margin and with 1 seta (broken in Fig. 4 A View Figure 4 ) apically at anterior edge; second segment with 7 setae; third segment with 4 setae along anterior margin, at distal margin with 2 short setae and 1 aes that is accompanied by 1 long seta arising from acrothek; fourth segment with 11 setae, six of which biarticulated, and 2 setae accompanying an aes.

Setal formula: I – 1; II – 7; III – 7 + aes; IV – 11 + aes.

A 2 (Fig. 4 B, B View Figure 4 *) with allobasis that carries 2 abexopodal setae but lacks an exopod; endopod with row of spinules proximally on the anterior and distally on the posterior margin; at its distal half it bears 4 long spinules and 3 setae, one of which bipinnate and the others bare. At its posterior edge, the endopod bears 2 cuticular frills (Fig. 4 B View Figure 4 *), the first one armed with spinules, apically with 6 elements: 1 unipinnate spine and 1 longer unipinnate seta, plus 3 long geniculate setae (one broken in Fig. 4 B View Figure 4 ), the outermost fused to a tiny bare seta (broken in Fig. 4 B View Figure 4 ).

Md (Fig. 5 A View Figure 5 ) produced into long gnathobase that ends in 2 strong and bicuspidate teeth and 1 less strong element that ends in four fine tips; apart from that, the gnathobase lacks any ornamentation. Mandibular palp 1 - segmented, with 1 basal (Fig. 5 A View Figure 5 : seta no. 2), 1 exopodal (6), and 3 endopodal setae (3–5); basal seta no. 1 completely reduced (Fig. 5 A View Figure 5 : asterisk *).

Mxl (Fig. 5 B View Figure 5 ) with praecoxal arthrite bearing 7 strong apical spines, one of which unipinnate, and 2 surface setae. Coxa basally with few long spinules and apically with 1 unipinnate and 1 bare seta. Basis, endo- and exopod fused, carrying 3 lateral setae and 3 apical spines, one of which unipinnate.

Mx (Fig. 5 C View Figure 5 ) syncoxa with 2 endites and few long spinules along distal margin. Both endites of similar shape, not fused to syncoxa, and carrying each 2 bare setae and 1 strong unipinnate spine fused with the segment. Allobasis distinct, also with long spinules at distal margin and produced into strong bare claw; additionally, with 2 bare setae and 1 bare spine. Endopod small and knob-like, equipped with 2 bare setae.

Mxp (Fig. 5 D View Figure 5 ) slender; syncoxa apically with row of spinules and 1 bare seta; basis about 1.6 times longer than syncoxa, with row of long spinules at outer margin; endopod produced into bare, lean claw longer than basis and accompanied by 1 tiny seta at its base.

P 1 – P 4 with transversely elongated bases that present a row of long spinules at their anterior margins and 1 outer seta (broken in all corresponding figures); P 2 – P 4 bases additionally with long tube pore. Intercoxal sclerites (exemplified by that from the P 2) long and bow-like. Endopods 2 - segmented (except male P 3 endopod; see below), exopods P 2 – P 4 3 - segmented.

P 1 (Fig. 6 A View Figure 6 ) basis additionally with 1 bare inner seta; enp 1 without setae or spinules, enp 2 with few long spinules at inner and outer margins and with 2 apical bare setae, the inner one being slightly longer than the outer one. Exopod 2 - segmented, exp 1 carrying 1 long bipinnate outer seta; exp 2 more than 2 times longer than exp 1, outer unipinnate seta arising at distal third, 4 geniculate bare setae inserting apically.

P 2 – P 4 (Figs 6 B View Figure 6 , 7 A View Figure 7 , 8 A View Figure 8 ) with enp 1 being unarmed and much shorter than enp 2; P 2 enp 2 (Fig. 6 B View Figure 6 ) with some spinules at inner and outer margins and 1 biplumose apical seta that exceeds the length of the whole exopod. P 3 and P 4 endopods (Figs 7 A View Figure 7 , 8 A View Figure 8 ) without spinules but bearing 2 apical setae: the inner one short and bare, the outer one bipinnate and about 4 times longer than the inner one in the P 3 (Fig. 7 A View Figure 7 ), whilst biplumose and nearly 5 times longer than the inner one in the P 4 (Fig. 8 A View Figure 8 ). Exopods with slender segments of increasing length from exp 1 to exp 3. All segments except P 4 exp 3 with rows of spinules at inner and / or outer margin; exp 1 with long outer seta, exp 2 with 1 outer and 1 inner seta, the latter bipinnate (P 2), bare (P 3), or biplumose (P 4). Exp 3 as depicted with 2 uni- or bipinnate outer setae, as well as with 2 apical setae (unipinnate in P 2, bare in P 3, and biplumose in P 4); P 2 and P 4 additionally with 1 inner seta (uniplumose in P 2, biplumose in P 4), P 3 with 2 bare inner setae. P 2 and P 3 with long tube pore located between the outer elements. Setation of P 1 – P 4 as given in Table 3 View Table 3 .

P 5 (Fig. 9 A View Figure 9 ) with slender basoendopod that bears a row of long spinules along anterior margin and a long bare outer seta arising from short, square setophore and accompanied by long tube pore; endopodal lobe completely incorporated into basis, with 2 bare setae and 1 tube pore. Exopod long and slender, approximately 1.5 times longer than basoendopod, with 1 outer unipinnate and 1 inner bare seta, 1 bare subapical seta shifted to the posterior surface, and 2 apical bipinnate setae.

P 6 and GF (Fig. 9 B View Figure 9 ). P 6 small, lobes fused to a narrow clasp-like structure that carries 1 bare seta on each outer side; close to the gonopore, that “ clasp ” bulges out slightly, being strengthened by a pair of sclerotised “ ribs ”.

Description of male.

Male resembling female in most aspects, except in the shape of the A 1, P 3, and P 4 endopods and P 5.

Habitus (Fig. 10 View Figure 10 ) as in female but smaller, slenderer, and lacking GDS. Body length from rostral tip of PT 6 to end of FR 376 µm (mean: 374 µm, range: 352–401 µm, n = 4). Rostrum (Fig. 11 A View Figure 11 ) fused with cphth, strongly constricted, slightly longer than broad, and cleft at its tip, with 2 sensilla; tube pore not recognisable in any of the four males.

A 1 (Fig. 11 B View Figure 11 ) consisting of 6 segments, chirocer, geniculation between fifth and sixth segments. The first two segments longest, the third and sixth segments slightly shorter than the fifth one, which is slightly swollen; acrothek not discernible; the fourth segment minute, unarmoured. Setal formula: I – 1; II – 7; III – 4; IV – 0; V – 9 + aes; VI – 9 + aes.

P 3 exopod as in female. Endopod 3 - segmented (Fig. 7 B View Figure 7 ), enp 1 tiny and bare, enp 2 more than three times longer than enp 1, ending on inner apical edge in cuspidal apophysis that slightly overtops the apical margin of enp 3. The latter is as long as enp 1 and bears 2 apical bare setae, the outer one being approximately seven times longer than the inner one.

P 4 exopod as in female. Endopod 2 - segmented (Fig. 8 B View Figure 8 ), enp 1 small, nearly squarish, and bare. Enp 2 about 3.4 times longer than enp 1, apically with 2 setae, the inner one bare, the outer one approximately 3.4 times longer than the inner seta and biplumose. Subapically on the outer margin arises 1 bipinnate spine.

P 5 (Fig. 9 C View Figure 9 ) generally as in female but smaller. Basoendopod more compact than that of female, without spinulose row; endopodal area with 2 bare setae and small tube pore. Exopod only slightly longer than basoendopod, without spinulose ornamentation, setation as in female, likewise with 1 tube pore.