Breviconia andrei sp. nov.

urn:lsid:zoobank.org:act: AC9FBB8B-43E3-4D51-AB2E-BBDF2539D413

Figs 2–9

Etymology

This species is named in honour of Professor Andrey Azovsky of Lomonosov Moscow State University, a Russian theoretical ecologist, our colleague, friend, and the husband of the first author.

Type material

Holotype RUSSIAN FEDERATION • ♀, dissected on 4 slides; the Bering Sea, Khatyr Depression; 61°10'50.5" N, 174°51'3.2" E; depth 402 m; deep mud; 29 Jun 2018; V. Mordukhovich leg.; IORAS-Har229–232.

Allotype RUSSIAN FEDERATION • ♂, dissected on 4 slides; same collection data as for holotype; IORAS- Har233–236.

Paratypes RUSSIAN FEDERATION • 1 ♀, dissected on 4 slides; same collection data as for holotype; MIMB 42333–42336 • 1 ♂, dissected on 4 slides; same collection data as for holotype; MIMB 42337–42340 • 2 ♀♀, whole body specimens on 1 slide; same collection data as for holotype; IORAS-Har237 • 2 ♂♂, whole body specimens on 1 slide; same collection data as for holotype; IORAS-Har238 .

Other material

RUSSIAN FEDERATION • 30 ♀♀ and 90 ♂♂, alcohol preserved; same collection data as for holotype; IORAS INV0000794 • 14 ♀♀ and 35 ♂♂, alcohol preserved; same collection data as for holotype; MIMB 42341 .

Description of the adult female

BODY (Fig. 2A–B). The total body length was 832 μm (mean 828 μm, n = 10) for the type specimen illustrated in Fig. 2A, measured from anterior tip of rostrum to posterior margin of the CR. Body slightly dorsoventrally depressed, tapering posteriorly, without clear demarcation between the prosome and urosome. Integument moderately sclerotized. Rostrum (Fig. 3A) small and prominent, having tube pore, laterally with 2 sensilla, inserting from the cuticular projection. Cphth wider than long, laterally with 5 pairs of moderate cuticular processes, each bearing sensillum terminally. Posterior margin with 4 small knob-like sensilla-bearing cuticular processes. Cphth dorsally and dorsolaterally with 4 pairs of sensilla. All body somites except penultimate somite and telson somite with pair of backwards produced lateral wing-like and spinulose processes and dorsolaterally produced paired, sensilla-bearing tubercles. P2– P5-bearing somites additionally with laterodorsal processes and with dorsal, sensilla-bearing tubercles. Sensillar shape characteristic for the Ancorabolinae, arising from cup-shaped tip of respective process and inserting like ball-and-socket joint (Fig. 2E), as described by George (2020: 479). Anal operculum dorsally with small spinules laterally flanked by pair of sensilla arising from small knob-like bases.

CR (Fig. 2B–D). Approximately 3 times as long as broad, tapering distally, with 1 tube pore laterally (Fig. 2D; arrow) and the following setae: I and II laterally at half-length of ramus, II longer than I. III, IV, V, and VI terminally, VI very small, V being longest. VII arising dorsally, tri-articulated.

GDS (Fig. 2F). The last thoracic and first abdominal somite fused to form genital double somite, original separation indicated by row of small spinules and dorsal cuticular processes, and by position of lateral cuticular processes. Gonopore located ventrally in the middle of the somite. P6 small, forming genital operculum, with 3 setae.

A1 (Fig. 3A–C). 3-segmented segments lacking coverage with tiny spinules. First segment medially on outer side with 2 rows of spinules and 1 bipinnate seta, located half-length on outer margin, with 9 bare setae inserting on distal half. Second segment almost as long as first segment, bearing 6 bare setae and 1 aesthetasc, which is fused with 1 bare seta. Third segment shortest, with 7 bare setae, 1 small aesthetasc, and 3 additional setae. Setal formula: 1-[10], 2-[6+(1+ae)], 3-[7+(3+ae)].

A2 (Fig. 3D). With allobasis, exopod absent. Allobasis almost as long as enp, on outer margin with 2 bipinnate setae; additionally, 4 spinules situated proximally and 4 spinules distally. Endopod with 3 bare setae and row of long spinules on outer margin. Inner margin with 5 rows of short spinules. Apically with 1 short spine, 1 long seta and 3 geniculate setae, the longest basally fused with 1 small bare seta.

MD (Fig. 4C). Coxa unarmed, cutting edge elongate and bent at nearly 90°, with 5 teeth. Basis, endopod and exopod fused to 1-segmented mandibular palp carrying 5 setae and 5 spinules apically.

MXL (Fig. 4A). Arthrite of praecoxa terminally with 4 bare setae, one of which very strong, and 1 strong bipinnate seta. Subapically on surface with 1 bare and 1 bipinnate seta. Coxa with 1 bare and 1 strong bipinnate seta. Basis, enp and exp fused to 1-segmented palp with 2 rows of spinules. Proximal part of basal endite with 3 bare setae, one of which short and strong. Distal part of basal endite with 2 bare setae. Endopod represented by 1 bipinnate seta, exopod by 2 bare setae.

MX (Fig. 4B). Syncoxa with row of strong spinules and 2 endites, each with 1 bipinnate and 1 smaller, bare seta. Basis fused with syncoxa, bearing 3 bare setae, one of which fused to basis and transformed into long claw-like element, to which a fourth seta is fused. Endopod reduced, represented by 2 bare setae.

MXP (Fig. 4D). Prehensile, syncoxa unarmed. Basis with row of long spinules. Endopod transformed into large claw, which is longer than basis, without accompanying minute seta.

P1 (Fig. 5A). With transversely elongated basis bearing 1 inner and 1 outer pinnate seta. Exopod 2-segmented, exp-1 with row of long spinules on outer border and 1 outer spine. Exp-2 with patches of spinules on both borders and 2 outer bipinnate spines, terminally with 2 long bipinnate geniculate setae and 1 very long plumose geniculate seta. Endopod 2-segmented, first segment being twice as long as exopod, with row of long spinules on distal half of inner border. Enp-2 terminally with 2 long geniculate setae, 1 short bare seta subterminally on inner side, and 2 rows of long spinules on outer and inner margins.

P2–P4 (Figs 5B, 6A–B). With transversely elongated bases, 3-segmented exopods and 2-segmented endopods. Exp-1 and exp-2 with 2 rows of long spinules on inner and outer margins, exp-3 with 1 row of spinules on outer border. Exp-2 of P2–P4 with very long inner plumose seta; exp-3 of P2–P4 without inner seta, with 2 outer and 2 terminal setae. Enp-1 of P2–P4 small and unarmed. Enp-2 of P2 with row of long spinules on outer margin and 2 patches of spinules on inner margin. Additionally, with 1 long plumose inner seta on proximal half and 2 very long terminal plumose setae. Enp-2 of P3–P4 with rows of spinules on outer margins; with 1 inner seta on proximal half, 1 subterminal outer seta and 2 terminal setae; all setae biplumose. The setal formula is given in Table 1.

P5 (Fig. 3E). Baseoendopod elongate, with 2 inner and 2 apical setae. Outer basal seta arising from long setophore that reaches ⅔ of length of exopod, with 5 long spinules at base. Exopod 6 times as long as wide, with 2 outer spines, 2 terminal biplumose setae, and 1 densely bipinnated inner seta.

Description of the adult male

BODY (Fig. 7A–B). Total body length 505 μm (mean 498 μm, n = 10) for the specimen illustrated in Fig. 7A, measured from anterior tip of rostrum to posterior margin of CR. Body with pattern of processes and sensilla same as for female, except: Cphth terminally with pair of moderate cuticular processes, each bearing sensillum; first 4 thoracic somites with cuticular processes; P6-bearing somite and first abdominal somite (equivalent to the female GDS) with dorsolateral processes being stronger developed than in female; thoracic and abdominal somites except penultimate without rows of spinules on posterior margins.

A1 (Fig. 8A–D). Seven-segmented and subchirocer geniculation between segments 4 and 5; aesthetascs on segments 4 and 7; segment 4 swollen. Segment 1 anteriorly with 2 rows of spinules and with 1 dorsal seta. Segment 2 small, with 6 elements. Segment 3 represented by U-shaped sclerite. Segments around geniculation without modified elements. Setal formula: 1-[9], 2-[6], 3-[2], 4-[10+(2+ae)], 5-[1], 6-[1], 7-[7+(1+ae)].

A2, mouthparts, P1 and P2 as in female.

P3 (Fig. 9A). Exp as in female, enp modified, 3-segmented; enp-2 with row of spinules on outer margin and distal anterior surface produced into smooth recurved apophysis; enp-3 with 2 apical setae.

P4 (Fig. 9B). Exp as in female; enp 2-segmented, sexually dimorphic: broader than in female; enp-2 with row of spinules on outer margin, 2 terminal setae and 1 pinnate subterminal outer seta; inner seta lost.

P5 (Fig. 8E). Exp and benp separate. Outer basal seta arising from long setophore. Endopodal lobe reduced, bearing 2 setae of different lengths, inner seta strong and pinnate. Exp smaller than in female, nearly 3 times longer than broad, with 2 outer and 2 apical setae, and with 1 pinnate inner seta.

P6 (Fig. 7C). Asymmetrical, with only 1 functional member, represented by membranous flap, and its counterpart fused to somite.