Tetraleberis brevis (Brady 1902)

Tetraleberis brevis (Müller, 1890)

Asterope brevis Müller, 1890:239, pls. 25: figs. 10, 14; 26: fig.7; 27: figs. 7–10, 12, 15, 16.

Cyclasterope brevis.—Müller, 1906:33, 35; 1912:48, 49.—Hanai, 1959:425.

Cylindroleberis brevis.—Kajiyama, 1912b:617, figs. 32, 33. Cycloleberis brevis.—Skogsberg, 1920:442.—Poulsen, 1965:245. figs. 83, 84.—Hanai, et al, 1977:81.—Not Brady, 1902: 183, pl. 24: figs. 16–22 [= Amboleberis americana (Müller, 1890)].

HOLOTYPE.—None selected (16 syntypes).

TYPE-LOCALITY.—Coast of Japan near Enoshima at a depth of 21.9 m.

MATERIAL.—Through the courtesy of Dr. H.-E. Gruner, I received from the Zoological Museum, Berlin, a vial labeled “Types, Kat. Nr. 6909, Species Cyclasterope brevis (G. W. Müller, 1890), Fundort Japan, Enosima, gesammelt von Hilgendorf, determiniert von G. W. Müller”. The vial contained a 2nd vial with 13 whole specimens, mostly juveniles, 1 incomplete specimen that had been removed from the shell, 1 empty carapace, 1 left 2nd antenna, and 1 right maxilla. The largest whole specimen, an adult or A-1 female with small unextruded eggs, is described herein; it has been designated specimen 1 on the slides and vial returned to Berlin.

Through the courtesy of Dr. Torben Wolff, I received from the Zoological Museum of the University of Copenhagen, a specimen identified as Cycloleberis brevis by Poulsen (1965:245). The specimen was netted at Dana station 3668, 21°03′30″S, 149°45′E, Coral Sea, at 38 m water depth. The vial I received contained a right valve, a left 1st antenna, a left 2nd antenna, a right mandible and the proximal part of a left mandible, a right 5th limb, the upper lip and furca, all of C. brevis. The vial also contained the valves of a halocyprid. A supplementary description of the specimen of C. brevis. based on the available appendages is presented herein. I think it possible that this specimen represents a new species, but additional material is necessary to document this.

DISTRIBUTION.—Japan and Coral Sea. Depth 21.9–38 m (Figure 44).

DESCRIPTION OF FEMALE SYNTYPE, SPECIMEN 1 (Adult or A-1 instar) (Figures 45–47, Plates 28–33).—Carapace oval in lateral view with small incisur near middle of anterior margin (Figure 45a, Plate 28a,c–f); valve widest posterior to middle (Plate 28b), and more-or-less evenly rounded in anterior view (Plate 28c).

Ornamentation: Anterior margin without scalloped peripheral ridge (Plates 28c, 29a); surface without fossae or ridges; punctae visible at high magnification (Plate 29b–f); bristles emerging from open pores with rim consisting of concentric rings (Plate 29c,d), and from open pores with low pustulose rim (Plate 29 e,f); minute open pores without bristles, but with low narrow rim, sparsely distributed on valve surface (Plate 29b); minute open pores also observed on some rims consisting of concentric rings (Plate 29d).

Infold: Typical for genus (Plates 30–31).

Central Adductor Muscle Attachments: Typical for subfamily (Figure 45b, Plates 32–33).

Size: Length and height of specimen 1: 3.56 mm, 3.00 mm. Range for 3 syntypes (see Table 20): length 3.25–3.56 mm, height 2.68–3.00 mm.

First Antenna (Figures 45c, 46a): 1st joint with long lateral and medial hairs near ventral margin, and minute spines forming medial row near distal margin. 2nd joint: long medial and lateral hairs near ventral margin; dorsal margin with long proximal hairs and 5 bristles; lateral side with 5 or 6 bristles. 3rd joint: short ventral side with small bristle; long dorsal margin with 13 spinous bristles. 4th joint: short dorsal margin with 1 long spinous bristle; long ventral margin with 5 terminal bristles (1 long, 4 short). 5th joint: dorsal margin with stout sclerotized node proximal to middle; medial side with few long hairs distal to node; sensory bristle of 5th joint with 2 or 3 short proximal filaments and 14 or 15 long terminal filaments. 6th joint with spinous medial bristle extending past tip of a-bristle of 7th joint. 7th joint: a-bristle clawlike, bare, slightly longer than dorsal margin of 5th joint; b-bristle stout, about one and one-half times longer than a-bristle, with about 13 filaments including tip; c-bristle longer than sensory bristle of 5th joint, with tip broken but 13 filaments on remaining part. 8th joint: d-and e-bristles bare, with blunt tips reaching tip of sensory bristle; f-bristle about two-thirds length of c-bristle, with 12 ventral filaments; g-bristle about same length as c-bristle, with about 17 marginal filaments, excluding tip.

Second Antenna (Figure 45d,e): Protopodite with long hairs along ventral margin and on medial surface near ventral margin, and 1 short, bare, distal, medial bristle. Endopodite: 1st joint divided into proximal part with 3 small bristles, and distal part with 6 short bristles; 2nd joint bare, with well-defined sutures separating it from 1st and 3rd joints; 3rd joint with long terminal bristle. Exopodite: 1st joint with spines along dorsal margin, and 1 minute, straight, terminal, medial spine; bristle of 2nd joint about same length as 1st joint, with abundant short hairs along both margins; bristles of joints 3–8 with natatory hairs and stout proximal ventral spines; 9th joint with 5 bristles (3 long, with proximal ventral spines and natatory hairs, 2 short, with only natatory hairs); joints 2–8 with large basal spines; 9th joint with lateral spine about two-thirds length of joint; joints 2–8 with spines forming row along distal margin.

Mandible (Figure 46b): Coxale endite remained in mouth of specimen examined (Figure 46e); medial bristle near base of ventral branch fairly long. Basale endite: tip of endite with 6 end-type bristles with several sets of marginal spines, and 2 intermediate bristles with about 30 minute paired spines along distal part; ventral margin of endite with 10 triaenid bristles with 11–14 paired terminal teeth decreasing in length distally; medial side of endite with 6 dwarf bristles (distal of these longer than others). Basale: ventral margin with 9 or 10 triaenid bristles similar to those of endite followed by 2 or 3 longer spinous bristles; dorsal margin with 9 short bristles and 2 long, spinous, terminal bristles; medial side hirsute, with 3 or 4 minute bristles near ventral margin. Exopodite hirsute, reaching distal end of 1st endopodite joint, with 2 ventral bristles (distal of these short). Endopodite: 1st joint with 8 ventral bristles (1 of these very small); ventral margin of 2nd joint with bristles forming 2 distal groups (3 bristles in proximal group, 2 in other); dorsal margin of 2nd joint and medial surface near dorsal margin with numerous bristles (3 of the cleaning bristles with broad marginal spines); medial surface of 2nd joint with few short distal spines forming row; end joint with 3 long claws, 1 long lateral mid-bristle, and 1 long and 1 short ventral bristle.

Maxilla (Figure 47a): Epipodite with faint hairs, and tip reaching distal bristles on dorsal margin of basale. Endite I with 4 stout bristles; endite II with 1 small bristle and 2 long stout bristles; endite III with 1 long stout bristle and 3 long, fairly slender bristles; 8 or 9 short slender bristles present mostly anterior to bases of bristles of endite III. Basale: dorsal margin hirsute, with 10–13 proximal bristles with bases on medial side, and 6 or 7 distal bristles; ventral margin with 12 or 13 short bristles, 2 long distal bristles, and 1 long, spinous, terminal bristle; medial surface with 5 distal bristles (longest of these near ventral margin); lateral side with 1 short proximal bristle. Exopodite: short lobe with 1 long and 2 short bristles. Endopodite: 1st joint spinous, with 2 short, proximal, anterior bristles and 1 long spinous beta-bristle; end joint with 6 spinous bristles.

Fifth limb (Figure 47b): Dorsal margin of comb slightly convex, with abundant short hairs that continue along anterior margin, and 4 or 5 small proximal bristles; lateral side with stout, spinous, exopodial bristle almost reaching distal end of comb, 3 minute bristles just posterior to base of stout exopodial bristle, 8 small bristles near ventral margin just posterior to base of stout exopodial bristle, and 2 proximal and 2 distal bristles with bases almost on ventral margin; ventral margin with spinous bristles forming 2 rows (lateral row longer than medial row) except anteriorly where 6 bristles form single row (bristles in medial row with long flaring hairs near tip).

Sixth Limb (Figure 47c): Anterior margin with well-defined upper and lower sutures. Anterior margin dorsal to upper suture with bristles forming 3 rows: inner medial row with 18 short, stout, spinous bristles; middle row with 20 slender spinous bristles (distal of these longer than others); outer row with about 23 short, very slender, spinous bristles. Anterior margin between upper and lower sutures with 4 spinous bristles in inner row, 3 or 4 spinous bristles in middle row (the distal of these very long), and 8 short, slender, spinous bristles in outer row. A single row of about 24 slender bristles present near anterior margin of skirt between lower suture and point near ventral margin of skirt. Lateral flap with 5 or 6 slender hirsute bristles. Ventral margin of skirt with numerous bristles continuing almost to posterior tip of skirt. Posterior tip with 4 or 5 short, stout, hirsute bristles. Numerous small bristles present on medial surface near ventral margin of skirt. Five small bare bristles in place of epipodial appendage. Limb hirsute. No medial spines present in anterodorsal corner of trunk.

Seventh Limb: Each limb with 96–102 bristles, 48–52 on each side, each bristles with up to 7 bells; most bristle-bearing joints with 2 bristles, 1 on each side, but many distal joints with 3 or 4 bristles, 1 or 2 on each side. Terminus with opposing combs, each with about 24 teeth of various types.

Furca (Figure 45f): Each lamella with 4 stout main claws, 1 slender, spinous bristle between claws 3 and 4 (closer to claw 4), and 9 additional slender bristles following claw 4, main claws with teeth of equal length forming medial and lateral row along concave margin; some adjacent teeth with minute tooth between them; main claws with hairs along convex margin; bristle between claws 3 and 4 shorter than claw 4; bristles with stout and slender spines along margins; anterior margin of each lamellae with few hairs; long hairs along edge of joined lamellae posterior to bristles; space between claw 4 and following bristle wider on right lamella than on left.

Rod-shaped Organ (Figure 46d): Elongate with suture proximal to widened middle part, tapering to rounded tip (proximal part shown in Figure 45i).

Eyes: Medial eye without dark pigment, bare (Figures 45i, 46d). Lateral eye about same size as medial eye, pigmented light amber on preserved specimen, with about 40 ommatidia (Figure 45g,h).

Upper Lip (Figures 45i, 46e): Each lobe with few slender, hairlike, anterior spines, and long hairs along ventral and posterior surfaces; anterior of saddle also with few short hairlike spines; hirsute lateral flap present on each side of mouth.

Posterior of Body (Figure 45j): Hirsute.

Y-Sclerite (Figure 45k): Convex, dorsal socket near middle;

SUPPLEMENTARY DESCRIPTION OF FEMALE (A-1 instar?) DESCRIBED BY POULSEN (1965:245) (Figure 48).—Right valve without teeth visible along anterior part of dorsal margin (left valve not available for study); surface without scalloped ridge along anterior margin; surface appearing smooth, without fossae or ridges (Figure 48a).

Size: Length 2.2 mm (from Poulsen, 1965:245) (flattened right valve available to me about same length).

Left 1st Antenna (Figure 48b–d): 1st joint hirsute, with 1 minute distal medial spine. 2nd joint: hirsute with 4 dorsal bristles; lateral side with 3 distal bristles. 3rd joint: short ventral side with small bristle; long dorsal margin with 7 spinous bristles. 4th joint: short dorsal margin with 1 long spinous bristle; long ventral margin with 3 terminal bristles (1 long, 2 short). 5th joint: dorsal margin with stout sclerotized node near middle; medial side with long hairs near and also distal to node; sensory bristle of 5th joint with 4 short proximal filaments and 8 longer terminal filaments (proximal of the terminal filaments shorter than others and separated from them by small space). Bristles on joints 6–8 not examined in detail, but similar to those on right antenna illustrated by Poulsen (1965, fig. 83c).

Left 2nd Antenna (Figure 48e): Exopodite differs from illustration of Poulsen (1965, fig. 83e) in having 4 bristles (3 long, 1 short) on the 9th exopodial joint. Also, although the 1st endopodial joint bears 2 proximal and 4 distal bristles as illustrated by Poulsen (1965, fig. 83d), an additional proximal and distal bristle may have been present but subsequently broke off.

Right Mandible: Similar to left mandible illustrated by Poulsen (1965, fig. 83f–j) except for bristles and claws on end joint being normal for genus (3 claws, 1 long lateral bristle, 2 ventral bristles) (Figure 48f).

Maxilla: Not available for study.

Right 5th Limb: Differs from left limb illustrated by Poulsen (1965, fig. 84b) in having comb with 6 short lateral bristles near base of stout exopodial bristle (Figure 48g).

Sixth and 7th Limbs: Not available for study.

Furca: Similar to illustrations of Poulsen (1965, fig. 84f–f″).

Rod-shaped Organ and Eyes: Not available for study.

Upper Lip (Figure 48h): Each lobe with few slender, hairlike, anterior spines, and long hairs along ventral and posterior surfaces; anterior of saddle with few hairlike spines in addition to long hairs; hirsute lateral flap present on each side of mouth.