Chelicopia obex Kornicker 1992

Chelicopia obex

ETYMOLOGY.—From the Latin obex (bar, bolt, boom).

HOLOTYPE.—MNHN Os 462, undissected instar IV male in alcohol.

TYPE LOCALITY.—Sta 101-DS, 8 Apr 1977, NW Île du Lys, Glorioso Islands, 11°25′42″S, 47°19′30″E, depth 26 m.

PARATYPES.—Sta 101-DS: USNM 193713, instar IV male on slide and in alcohol.

DISTRIBUTION.—Collected only at type locality.

DESCRIPTION OF INSTAR IV MALE (Figures 90, 91).—Carapace oval in lateral view with small projecting posteroventral caudal process with rounded distal margin (Figure 90a–c). Rostrum absent.

Ornamentation: Surface with indistinct shallow fossae with rim of minute spines (on USNM 193713 fossae visible just on posterior part of shell) (Figure 90d). Minute spines forming intersecting rows (on USNM 193713 spines more clearly visible along shell margins, and especially in area of caudal process (Figure 90c) and along edges of valve (Figure 90c,e–g)).

Surface Bristles: Outside surface and valve margins with short and long bristles (Figure 90b). Long and short bristles along edge of valves generally with pointed tip, but those on lateral surface mostly with small bulbous tip (in Figure 90b the distribution of bulbous and pointed bristles are not accurately differentiated). Pointed bristles appear to merge from open pore (depression around base of bristle) whereas bulbous bristles emerge from closed pore (no depression around base of bristle). All bulbous bristles taper gradually to proximal end of bulb-like tip; most pointed bristles taper gradually to tip; however, a very few pointed bristles with slight broadening at the base.

Infold: Small bristle on anterior infold near inner margin usually present on the Sarsiellinae not observed on specimen examined (USNM 193713) (Figure 90e). Infold of caudal process with 3 or 4 small bristles forming row anterior to process and 6 smaller bristles (some in pairs) at inner margin of infold (Figure 90f,g); 2 or 3 setal bristles in row just dorsal to caudal process.

Selvage: Broad lameller prolongation along anterior, ventral, and posterior margins; long marginal fringe present on prolongation along anteroventral, ventral, and posterior margins of left valve, but absent along terminal square edge of caudal process (Figure 90g). Fringe not observed on lamellar prolongation of right valve.

Central Adductor Muscle Attachments (Figure 90a,h,i): Comprising 17 individual ovoid attachments.

Carapace Size: MNHN Os 462, holotype, length with caudal process 0.81 mm, length without caudal process 0.79 mm, height 0.70 mm; USNM 193713, length with caudal process 0.77 mm, height 0.71 mm.

First Antenna (Figure 90j,k): 1st joint bare. 2nd joint with minute spines forming proximal rows on medial surface near dorsal margin and along dorsal margin, and distal rows on lateral surface near dorsal margin, and 1 spinous dorsal bristle near midlength. 3rd joint fused to 4th, with 2 long spinous bristles (1 ventral, 1 dorsal). 4th joint with 2 spinous terminal bristles (1 long ventral, 1 short dorsal). Sensory bristle of long 5th joint with 1 fairly long proximal filament. 6th joint fused to 5th, with short spinous medial bristle. 7th joint: a-bristle more than twice length of bristle of 6th joint, bare; b-bristle minute, about length of bristle of 6th joint, with 1 minute spine (filament?) (Figure 90k); c-bristle longer than sensory bristle of 5th joint, with 2 fairly long proximal filaments. 8th joint (Figure 90j): d- and e-bristles slightly shorter than c-bristle, bare with blunt tips; f-bristle shorter than c-bristle, with 2 fairly long proximal filaments; g-bristle about same length as c-bristle, with 2 fairly long proximal filaments.

Second Antenna: Protopodite bare. Endopodite 3-jointed (Figure 90l): 1st joint with 2 small anterior proximal bristles; 2nd joint elongate, with 3 small proximal bristles; 3rd joint longer than 2nd, with 2 small terminal bristles. Exopodite: 1st joint with small straight terminal medial tubular bristle; bristle of 2nd joint long, with 8 stout proximal ventral spines and distal natatory hairs; bristles of joints 2–8 with ventral spines and distal natatory hairs (distal spines of bristles of joints 3–5 unusually long (Figure 90m)); ventral spines of bristle of 8th joint absent or relatively small; small 9th joint with 2 bristles (ventral bristle medium length, with natatory hairs, no spines; dorsal bristle minute, either bare or with few short hairs).

Mandible (Figure 91a–d): Coxale endite represented by stout spine with 2 minute marginal spines. Coxale with long hairs forming relatively short row along ventral margin. Basale: with 4 medial bristles (3 proximal forming cluster, and 1 distal and closer to ventral margin) and 3 lateral bristles near distal medial bristle; dorsal margin with 1 small subterminal spine-like bristle. Exopodite small with small ventral bristle at midlength (Figure 91a,b). 1st endopodial joint: dorsal margin with proximal angular corner and few terminal spines forming part of row extending onto medial surface of joint; medial surface with minute spines forming distal rows; ventral margin with stout terminal claw with 6 small dorsal ridges near tip, and small spines forming row proximal to ridges (spines arranged in 3 sets (Figure 91d)). 2nd endopodial joint with stout terminal claw with 10 short dorsal ridges near tip and minute spines forming row proximal to ridges. 3rd endopodial joint with stout terminal claw and 4 small bristles near base of claw (3 ventral, 1 dorsal) (Figure 91b).

Maxilla: Endite I with 5 bristles; endite II with 4 bristles, endite III with 6 bristles (Figure 91e). Coxale with short dorsal bristle (not shown). Basale with 1 short bristle near exopodite (bristle could be interpreted to be proximal on endite III) and few hairs on anterior margin. Exopodite small, with 2 bare bristles (Figure 91f). 1st endopodial joint with stout alpha- and beta-bristles and 3 sets of hairs along anterior margin (proximal set with stoutest hairs). 2nd endopodial joint with 2 short a-bristles (posterior longest and with few marginal spines), 1 short c-bristle, and 5 pectinate end bristles.

Fifth Limb (Figure 91g): Epipodial appendage with 34 bristles. Single endite with 1 small bare bristle. Exopodite: 1st joint with 3 bristles; joints 2–5 fused, with total of 11 or 12 bristles. Limb hirsute. All exopodial bristles ringed (not shown).

Sixth Limb (Figure 91h): Endite I with 3 bare bristles (2 long, 1 short). Endite II with 1 long bristle. End joint with 14 or 15 bristles (2 posterior bristles with long proximal and short distal hairs, remaining bristles with short hairs or spines). Limb hirsute (only few hairs shown). All bristles ringed (not shown).

Seventh Limb (Figure 91i): Well developed. Proximal group with 2 tapering bristles (1 on each side) on either the same segment or on adjacent segments, each bristle with 2 bells. Terminal group with 4 tapering bristles (2 on each side), each with 3 bells. Terminus with opposing small combs, each with 2 or 3 minute spine-like teeth (not all shown). (Tapering bristles a juvenile character.)

Furca (Figure 91j): Each lamella with 7 or 8 claws (USNM 193713 with 7 claws on left lamella and 8 on right); claws 1, 2, and 4 primary, nonarticulated, and with narrowly rounded tips; claw 3 and claws 5 to 7 or 8 secondary, articulated, and with pointed tips. Claw 1 with small slender proximal teeth forming medial row, longer teeth forming lateral row (4 distal teeth very large), and few hairs along anterior margin. Claw 2 with teeth along posterior margin (some longer than others) and few hairs along anterior margin. Claw 4 with small teeth (some larger than others) along posterior margin and few hairs along anterior margin. Claw 3 with minute teeth along posterior margin and few teeth along anterior margin. Claws 5–7 or 8 with minute teeth along posterior margin and fewer similar teeth along anterior margin. Long hairs on lamellae following claws and also medial to the secondary claws following primary claw 4. 2 indistinct spines on each lamella following last claw and near proximal end of lamella (Figure 91j). Right lamella anterior to left by width of claw 1 at base.

Bellonci Organ (Figure 90n): Elongate, broadening to rounded tip, with weak sutures.

Eyes: Lateral eye unpigmented with 10 amber-colored ommatidia (5 large, 5 small, all divided by a suture) (Figure 91k,l). Medial eye about same size as lateral eye, bare, unpigmented (Figure 90n).

Upper Lip (Figure 91m): Evenly rounded and with few long ventral hairs.

Genitalia (Figure 91n): Comprising 2 small lobes on each side of body anterior to furca (lobes containing small globules or cells).

Anterior of Body (Figure 91m): Small triangular process on anterior just dorsal to each mandible.

Posterior of Body: Long hairs forming lateral row just proximal to furca (Figure 91j,o); additional long hairs just dorsal to a small indentation posterior to posterior end of Y-sclerite (Figure 91o).

Y-Sclerite (Figure 91o): Typical for subfamily.

COMPARISONS.—Chelicopia obex is quite similar to C. arostrata, C. rotunda, and C. kornickeri, and all could be conspecific. Details of the appendages of some of the species are not known but from what is available it is apparent that their appendages are quite similar. I propose C. obex as a new species because of its projecung caudal process, which is not present on juveniles or adults of the 3 previously described species. However, because C. obex is known only from the instar IV male, it is not known whether the projecting caudal process also is present on the adult, but I here assume that it is.

For comparative purposes I examined the holotype of C. kornickeri McKenzie, 1965 (USNM 110912), and have illustrated some of the appendages (Figure 92).

Eurypylus Brady, 1869

Eurypylus Brady, 1869:141.—Kornicker and McKenzie, 1976:348 [diagnosis, key].—Kornicker, 1986a:33 [key].

TYPE SPECIES.—Eurypylus petrosus Brady, 1869:141, monotypy.

DISTRIBUTION.—Continental shelf off Georgia, North America; mangrove area in vicinity of Tanzania, East Africa; Cape Verde Islands off West Africa; shallow water in vicinity of Singapore; Lizard Island lagoon, Australia. Herein: in vicinity of Mayotte and Glorioso Islands. Known depth range shallow water to 33 m.

COMPOSITION.—This genus includes 6 species: E. petrosus Brady, 1869:141; E. setifer (Poulsen, 1965:62); E. concentricostatus (Hartmann, 1974:235); E. pulcher Hall, 1985:500; E. rousei (Darby, 1965:37); and E. chavturi, new species.