Hadacypridina biscayensis Kornicker 1989

Hadacypridina biscayensis

Hadacypridina species A.—Komicker, 1985:410–412.

Metavargula species A.—Komicker, 1985:410–412 [only specimen from sample DS-60].

ETYMOLOGY.—Named after Bay of Biscay near where the specimens were collected.

HOLOTYPE.—Ovigerous female on slide and in alcohol, MNHN Os 93, Muséum National d'Histoire Naturelle, Paris, France.

TYPE LOCALITY.—BIOGAS IV, R.V. Jean Charcot, west of Bay of Biscay, 47°26′48″N, 9°07′12″W, 3742 m, sta 2, sample DS-60, 24 Feb 1974.

PARATYPES.—BIOGAS V, R.V. Cryos, sta 4: sample DS-68, 1 juvenile (instar III) MNHN Os 92. BIOGAS VI, R.V. Jean Charcot, sta 2: sample DS-75, 1 adult female, MNHN Os 91.

DISTRIBUTION.—West of Bay of Biscay at abyssal depths, 3250–4550 m.

DESCRIPTION OF ADULT FEMALE (Figures 9–11c).—Carapace oval in lateral view with narrow rostrum and narrow caudal process (Figures 9a–d, 11a,b); anterior of rostrum linear and forming point with incisur. Lateral surface of carapace smooth, but anterior margin near ventral curvature with minute serrations.

Infold (Figures 9b–d, 11a,b): Rostral infold with 10 small bristles; paired bristles at inner end of incisur (Figure 9b); 3 minute bristles posterior and ventral to incisur; list narrow, with anterior end about midway between incisur and ventral margin of valve, continuing posteriorly just within ventral margin, increasing distance from shell margin at posterior end, forming anterior margin of caudal process (Figure 9c,d); ridge bearing lamellar prolongation present along posterior edge of incisur increasing distance from shell edge at about anterior end of list and continuing just within shell edge, terminating at posterior corner of tip of caudal process; lamellar prolongation of selvage broad in vicinity of incisur, narrow elsewhere; list of caudal process of right valve forming broad process (Figures 9c, 11a,b); 1 or 2 minute bristles on infold of caudal processes and additional minute bristles along list of caudal process (Figure 9c,d); about 25 small bristles forming row just distal to list of anteroventral and ventral margins of each valve.

Central Adductor Muscle Attachments: Consisting of numerous oval individual scars.

Size: Holotype, length 2.52 mm, height 1.80 mm, height 72% of length; MNHN Os 91 length 2.46 mm, height not measured.

First Antenna: 1st and 2nd joints bare. 3rd joint with 2 bristles, 1 ventral, 1 dorsal. 4th joint with 2 terminal bristles, 1 ventral, 1 dorsal. Sensory bristle of 5th joint with 8 long proximal filaments and short, slender, distal filaments. Medial bristle of 6th joint about same length as combined joints 7 and 8. 7th joint: a-bristle stouter but about same length as bristle of 6th joint; b-bristle slightly longer than a-bristle, with 4 short marginal filaments; c-bristle about longer than sensory bristle of 5th joint, with 8 or 9 short filaments. 8th joint: well defined; bare d- and e-bristles about 3 times length of a-bristle; f-bristle about same length as sensory bristle of 5th joint, with 8 or 9 short filaments, some with marginal spines; g-bristle longer than f-bristle (tip missing on specimen examined and with 9 short filaments, some with marginal spines, on remaining part).

Second Antenna (Figure 9e): Protopodite with short medial bristle. Endopodite 2-jointed: 1st joint with 3 short and 2 longer bristles (distal of latter with marginal spines); distinct 2nd joint with 2 terminal bristles (1 short, 1 long). Exopodite: bristle of 2nd joint reaching joints 7 or 8, with 12 ventral spines (10th spine stouter than others, proximal spines and last 2 spines more slender than others); bristles of joints 3–8 with natatory hairs, no spines; 9th joint with 4 bristles (1 short, bare, or with short spines; 1 longer with natatory hairs, 2 very long with natatory hairs); joints 3–8 with very small basal spines; lateral spine of 9th joint about half length of joint and with marginal spine near tip.

Mandible (Figure 9f): Coxale endite spinous, with 2 terminal spines but no peg; small bristle at base of endite. Basale: ventral margin with 2 small unequal a-bristles, 1 small b-bristles, 2 c-bristles (1 short, 1 longer), and 2 d-bristles (1 short, 1 very long with wreaths of long hairs); dorsal margin with 3 bristles (1 distal to middle, 2 terminal). Exopodite about length of dorsal margin of 1st endopodial joint, hirsute distally and with 2 bristles (distal about length of other). 1st endopodial joint with 4 ventral bristles (2 short, 2 long). 2nd endopodial joint: ventral margin with single, small, pointed bristle and a terminal pair of slender pointed bristles (medial slightly stouter, unringed, and with marginal spine near tip); dorsal margin with 6 medium-to-long bristles and 6 short spinous bristles; medial surface with spines forming rows. 3rd joint with 2 stout claws, 2 ventral bristles (1 same length as claws, 1 shorter), and 2 short dorsal bristles (illustrated limb aberrant in having no claws and only 3 bristles).

Maxilla (Figure 10a): Thin epipodial appendage with faint hairs. Coxale with stout, plumose, dorsal bristle. Endite I with 7 spinous bristles (3 with knife-like tips, 2 with bifurcate tips, none with marginal teeth); endite II narrower than endite I, with 5 spinous bristles; endite III narrower than endite II, with 4 bristles (3 stout spinous, 1 slender bare). Basale with 2 or 3 (1 short, 1 or 2 long) bristles along distal margin. Exopodite stout, with 3 bristles (proximal bristle and outer terminal bristle plumose, inner terminal bristle with short marginal hairs). 1st endopodial joint with stout cutting tooth with 2 cusps, short hairs along dorsal margin, 2 alpha-bristles (inner bristle with short marginal hairs, outer bristle longer and with long marginal hairs), and 2 beta-bristles (outer of these stout, pectinate). 2nd joint with 4 a-bristles (some with minute marginal teeth), 3 pectinate b-bristles, 2 pectinate c-bristles, and 3 pectinate d-bristles.

Fifth Limb (Figure 9g,h): Epipodial appendage with 46 bristles. 3 endites present: endite I with 5 bristles; endite II with 1 small bare bristle and 4 spinous bristles; endite III with 7 spinous or pectinate bristles. Anterior tooth of protopodite undulate (Figure 9h). 1st exopodial joint: anterior side with 3 bristles forming group near inner side of joint (2 inner bristles long, stout, with long proximal hairs and short distal spines; outer bristle short with long proximal hairs), and near middle of joint 1 bristle with long proximal hairs; main tooth consisting of smooth peg and 6 constituent pectinate teeth; 1 spinous bristle on posterior side proximal to peg. 2nd exopodial joint with 1 proximal posterior bristle with long proximal and short distal hairs, 4 strongly pectinate a-bristles, 3 pectinate b-bristles, and 3 pectinate b'-bristles. 3rd exopodial joint: inner lobe with 3 spinous bristles, outer lobe hirsute, with 2 bristles with long proximal and short distal hairs. Hirsute 4th and 5th exopodial joints fused, with small node representing division between joints; 2 spinous bristles on each joint.

Sixth Limb (Figure 10b): 4 bare bristles in place of epipodial appendage. Endite I with 2 hirsute medial bristles and 1 spinous terminal bristle; endite II with 3 hirsute medial and 2 spinous terminal bristles; endite IV with 1 medial and 2 terminal spinous bristles. End joint with 3–7 anterior bristles with long proximal and short distal spines followed by space and 3 or 4 bristles (1 or 2 with long proximal and short distal spines, and 2 posterior, hirsute). Endites III and IV and end joint hirsute. (Holotype with 6 bristles on end joints of both limbs; paratype with 8 bristles on 1 limb and 10 on other.)

Seventh Limb (Figure 10c): Proximal group with 8 bristles (4 on a side) each with 4 bells; terminal group with 8 bristles on comb side and 6 bristles on peg side, each with 1–5 bells. Comb indistinct but with about 7 short straight teeth; peg opposite comb recurved.

Furca (Figure 10d): Each lamella with 9 claws decreasing gradually in length posteriorly, all separated from lamella by distinct suture; teeth along posterior margin of claws having similar length; right lamella slightly anterior to left.

Bellonci Organ (Figure 9i): Small, elongate.

Eyes: Lateral eyes absent. Medial eye not seen.

Upper Lip (Figure 10e): Consisting of unpaired anterior part with fairly large glandular processes, and paired tusks with large glandular processes; posterior lobe hirsute.

Genitalia: Oval sclerotized ring with attached round spermatophore on each side of body anterior to furca.

Posterior of Body: Bare and without processes.

Y-Sclerite: Typical for Cypridininae.

Eggs: Holotype with 14 eggs in marsupium.

DESCRIPTION OF JUVENILE (instar III) (Figure 11d–f).—Carapace similar in outline to that of adult female (Figure 11d).

Infold: In general, similar to that of adult female but with fewer bristles.

Size: Length 1.30 mm, height 0.93 mm, height 72% of length.

First Antenna (Figure 11e): 1st and 2nd joints bare. 3rd joint with 1 ventral bristle on left limb, and 2 bristles (1 ventral, 1 dorsal) on right limb. 4th joint with short dorsal bristle. Sensory bristle of 5th joint with 4 long proximal filaments and 1 short distal filament. 6th joint with small medial bristle; a–g bristles of joints 7 and 8 present but not examined in detail.

Second Antenna: Protopodite with small distal medial bristle. Endopodite 2 jointed (similar to that of adult female): 1st joint with 1 anterior bristle; 2nd joint with 2 terminal bristles (1 long, 1 minute). Exopodite 9-jointed: bristle of 2nd joint reaching 8th joint, with ventral spines; bristles of joints 3–8 with natatory hairs; 9th joint with 3 bristles (1 short, bare, 2 long with natatory hairs).

Mandible: Right mandible aberrant, without 2nd and 3rd endopodial joints: 1st joint with 2 long terminal bristles. Left mandible similar to that of adult female paratype except ventral margin of 2nd endopodial joint with only 3 bristles (2 long, 1 short) and ventral margin of 3rd joint with 3 bristles; number of dorsal bristles on 2nd joint not counted.

Maxilla, Fifth Limb, Sixth Limb: Well developed but not studied in detail.

Seventh Limb (Figure 11f): Small, bare.

Furca: Each lamella with 5 claws, all separated from lamella by well-defined suture.

Bellonci Organ (Figure 11e): Small, and poorly defined.

Eyes: Medial eye if present, without pigment and not well defined. Lateral eyes absent.

Upper Lip, Y-sclerite, Posterior of Body: Similar to those of adult female. Posterior of body without dorsal process or spines.

DISTRIBUTION.—Widespread, especially in deep water and cold regions; the southernmost record is in the Weddell Sea (72°47′30″S, 30°28′18″W) and the northernmost record is west of the Bay of Biscay. Previous known depth range of the genus was 117–3658 m. In the present study the genus was collected at depths of 1845–4240 m, slightly extending the depth at which the genus has been collected.

COMPOSITION.—Three species of Metavargula were collected in the study area, all new: M. quintuplex, M. bilix, and M. hex.

I herewith propose that Cypridina nobilis Cleve, 1905, collected at 450 m depth off South Africa (Cleve, 1905:134), be referred to Metavargula, as Metavargula nobilis, because of the broad flat filaments on the sensory bristle of the 5th joint of the male 2nd antenna (Cleve, 1905, pl. 7: fig. 4). Males of Bathyvargula also have flat filaments, but species of that genus seem less common than species of Metavargula. The referral must be considered tentative until the species is better known.