Eusarsiella gomoiui (Kornicker & Caraion 1978)

Sarsiella gomoiui

HOLOTYPE.—“Grigore Antipa” 464, adult female in alcohol, length 1.35 mm.

TYPE-LOCALITY.—Station X048.

ETYMOLOGY.—The species is named for Dr. Marian Trouian Gomoiu, Romanian Institute of Marine Research, Constanta, Romania.

ALLOTYPE.—USNM 156651, adult male from station X048.

PARATYPES.—From station X048: USNM 156687, 1 ovigerous female; USNM 156649, 1 ovigerous female; USNM 156993, 1 adult male, 2 ovigerous females, 2 adult females with choniostomatid egg sacs (valves not opened), and 7 juveniles; [USNM 156652], 1 adult male.

ADDITIONAL MATERIAL.—USNM 156994, adult female with caudal process missing, from station X070.

DESCRIPTION OF ADULT FEMALE (Figures 32–35; Plates 17–20).—Carapace oval in lateral view with prominent caudal process but without rostrum or incisur (Figure 32).

Ornamentation (Figure 32; Plates 17–20): Each valve with flat central area with peripheral ridge (Plates 17, 18); an additional ridge lying within and parallel to anterior and ventral parts of peripheral ridge with low processes; posterodorsal and posterior processes more prominent than other processes; surface with abundant shallow fossae and minute spines between fossae (Plates 17, 18, 19a–d, f); SEM micrographs reveal marginal pustules on spines (Plate 20a,c–f); long bristles present along anterior and ventral margins and scattered over valve surfaces (Plates 17, 18, 19a,d,f, 20b); surface covered by gelatinous substance.

Infold: Anterior infold with single minute bristle ventral to middle of anterior margin; infold of caudal process with 5 or 6 bristles near middle (forming row or scattered) and 1 additional bristle closer to inner margin (Figure 33); ventral infold just anterior to caudal process with few minute bristles along inner margin; 2 setose bristles present dorsal to caudal process (Figure 33).

Selvage (Plate 19d,e): Anterior selvage with smooth margin.

Size (Figure 10): USNM 156649, length 1.39 mm, height including caudal process 1.23 mm, height excluding caudal process 1.18 mm. USNM 156687, length 1.33 mm, height including caudal process 1.32 mm, height excluding caudal process 1.17 mm. USNM 156993, 2 ovigerous females: length 1.38 mm, height including caudal process 1.27 mm; length 1.36 mm, height including caudal process 1.21 mm. Holotype, “Grigore Antipa” 464, length 1.35 mm, height including caudal process 1.27 mm.

First Antenna (Figure 34a): 1st joint: bare. 2nd joint: spinous dorsal bristle and few spines along dorsal and ventral margins. 3rd joint: short, fused to 4th, with 2 spinous bristles (1 dorsal, 1 ventral). 4th joint: elongate, with 3 bristles (1 dorsal, 2 ventral). 5th joint: sensory bristle with 2 minute filaments (1 proximal, 1 subterminal). 6th joint: medial bristle short with base near dorsal margin. 7th joint: a-bristle spinous; b-bristle slightly longer than a-bristle, bare; c-bristle same length as sensory bristle of 5th joint, with 3 minute marginal filaments (2 proximal, 1 subterminal). 8th joint: d- and e-bristles bare, slightly shorter than c-bristle; f- and g-bristles same length as d- and e-bristles; f-bristle with 2 minute filaments (1 proximal, 1 subterminal); g-bristle with 3 minute marginal filaments (2 proximal, 1 subterminal); minute spine at tip of sensory, c-, f-, and g-bristles.

Second Antenna: Protopodite bare. Endopodite 1-jointed with 2 short, proximal, anterior bristles and 1 spinous terminal bristle (Figure 34b). Exopodite: 1st joint with minute, recurved, medial bristle on distal margin; bristle of 2nd joint reaching past 9th joint, with 13 slender ventral spines proximal to middle and natatory hairs distally; bristles of joints 2–8 with natatory hairs and without ventral spines; 9th joint small, with 1 long bristle with natatory hairs and 1 short bare bristle; joints 2–8 with short spines forming distal row along lateral margin; no basal spines.

Mandible (Figure 34c): Coxale endite consisting of sharp spine; ventral margin of coxale with long hairs. Basale: medial surface near ventral margin with 2 short bristles (1 proximal, 1 near middle); ventral margin with 2 short proximal bristles; lateral side with 2 short bristles near middle; dorsal margin with 2 minute subterminal bristles. Endopodite: 1st joint with medial spines forming pattern distal to middle; a single row of distal spines present on dorsal corner extending from medial side onto dorsal margin (unclear as to whether dorsal spines are stouter than medial spines or whether one of the dorsal spines should be considered to be a minute bristle); main claw of 1st joint with minute proximal spines along dorsal margin; 2nd joint with short, subterminal, dorsal bristle and smooth main claw; 3rd joint with 2 small bristles, 1 ventral, 1 dorsal, at base of smooth main claw. No exopodite.

Maxilla (Figure 34d): Coxale with short dorsal bristle. 3 endites present. Exopodite with 2 bristles. Endopodite: 1st joint with pectinate α- and β- bristles; 2nd joint with 2 short a-bristles, 1 short c-bristle and 5 pectinate end bristles.

Fifth Limb (Figure 34e): Epipodial appendage with 33 bristles. Single endite with 1 short bristle. Exopodite: 1st joint with 2 spinous bristles; fused joints 2–5 hirsute, with total of 8 or 9 bristles.

Sixth Limb (Figure 35a): Single endite with 2 or 3 bristles; end joint with 12 spinous bristles plus 2 hirsute posterior bristles; limb hirsute along posterior margin.

Seventh Limb (Figure 35b): 2 bristles in proximal group (1 on each side), 6 bristles in terminal group (3 on each side), each bristle with 3–6 bells and without marginal spines, bells decrease in size gradually towards tip of bristle; terminus with opposing combs, each with 5 or 6 recurved teeth.

Furca (Figure 35c): Each lamella with 5 slender claws; claw 1 united to lamella; claws 2–5 separated from lamella by suture; teeth present along posterior margins of claws; several spines present on margin of lamella following claws.

Rod-shaped Organ (Figure 35d): Elongate, 1-jointed with rounded tip.

Eyes: Lateral eye with 4 ommatidia (Figure 35e); medial eye slightly larger than lateral eye, bare, pigmented (Figure 35d).

Upper Lip (Figure 35d): Helmet shaped.

Y-Sclerite (Figure 35f): Typical for family.

Eggs: USNM 156649 with 7 eggs in marsupium plus smaller unextruded eggs; USNM 156687 with 6 eggs in marsupium.

Parasites: 2 adult females (USNM 156993) with choniostomatid egg sacs visible through ostracode shell.

DESCRIPTION OF ADULT MALE (Figures 36–38; Plates 21–24).—Carapace elongate with prominent rostrum and truncate posterior (Figure 36).

Ornamentation (Figures 36, 37a; Plates 21, 22a–e, 23c–e): Upper ridge extending from anterior of rostrum to posterior part of valve and there terminating in 2 elongate processes (Plate 21); lower ridge extending from anteroventral tip of rostrum to posterior part of valve and there connecting with upper ridge at base of posterior process; a second ridge lying between central muscle attachment area and lower ridge and intersecting it anteriorly near rostrum and posteriorly near caudal process. Surface with shallow fossae (Figures 36, 37a; Plates 21, 22a,b); area between fossae with abundant spines (Plate 21, 22a,b,e); surface of spines papillate (Plates 22c,d, 23c-e).

Infold: Anteroventral infold with minute bristle about half way between ventral margin of valve and ventral margin of rostrum; caudal process with 3 or 4 bristles near middle and 1 bristle closer to inner margin of infold (Figure 37b; Plates 22f, 23b, f); 2 setose bristles present on posterior infold.

Central Adductor Muscles (Plate 24): Consisting of about 10 ovoid individual muscles.

Size (Figure 10): USNM 156651, length 1.31 mm, height 0.84 mm; USNM 156652, length 1.32 mm, height 0.87 mm; USNM 156993, length 1.28 mm, height 0.86 mm.

First Antenna (Figure 37c): 1st joint: few minute, faint spines forming row on lateral and medial surfaces near dorsal margin. 2nd joint: faint spines forming rows on lateral and medial surfaces and 1 subterminal dorsal bristle. 3rd and 4th joints: fused; 3rd joint with 1 dorsal bristle and short ventral bristle; 4th joint with 3 bristles (2 ventral, 1 dorsal). 5th joint: minute, sensory bristle with cuplike basal part with numerous filaments, and stem with 4 marginal filaments and 2 minute spines at tip. 6th joint: short medial bristle. 7th joint: a-bristle bare, longer than joints 5–8 combined; b-bristle slender, bare, about one-third longer than a-bristle; c-bristle reaching past tip of sensory bristle of 5th joint, with 5 marginal filaments and 2 minute spines at tip. 8th joint: d- and e-bristles bare with blunt tips not reaching tip of sensory bristle; f-bristle slightly longer than d-bristle, with 4 marginal filaments and 2 minute spines at tip; g-bristle reaching just past tip of sensory bristle, with 4 marginal filaments and 2 minute spines at tip.

Second Antenna: Protopodite bare. Endopodite 2-jointed: 1st joint with 2 small anterior, proximal bristles; 2nd joint small with 3 bristles (Figure 37d). Exopodite: 1st joint with minute, recurved, medial spine on distal margin; bristle of 2nd joint with few natatory hairs proximally on ventral margin followed by 8–10 slender ventral spines and, then, natatory hairs on both margins; bristle of joint 3 with no or 4 spines and natatory hairs; bristles of joints 4–8 with natatory hairs but no spines; 9th joint with 2 bristles with natatory hairs (dorsal of these short).

Mandible (Figure 37e): Coxale endite represented by slender spine with faint annulae; ventral margin of coxale without hairs or spines. Basale: medial side with 4 bristles (1 near middle, 3 proximal) all near ventral margin; ventral margin with 2 bristles near middle; dorsal margin with 2 bristles. Exopodite hirsute, with base on lateral side of basale and distal part medial to 1st endopodite joint. Endopodite: medial side of 1st joint with long hairs near dorsal margin and shorter hairs and spines elsewhere; ventral margin with 2 terminal bristles (1 of these minute); 2nd joint with medial spines, 1 dorsal midbristle, and 1 ventral terminal bristle; 3rd joint with stout terminal claw and 3 bristles (2 ventral and 1 dorsal to base of claw).

Maxilla (Figure 37f): Precoxale and coxale with fringe of hairs dorsally; coxale with 1 dorsal bristle. 3 endites with weak bristles present. Exopodite with 2 bristles. Bristles of basale and endopodite weak, indistinct. Limb reduced.

Fifth Limb (Figure 37g): Single endite with 1 short bristle. Exopodite: 1st joint with 2 spinous bristles; joints 2–5 fused, hirsute, with total of 8 bristles.

Sixth Limb (Figure 38a): Single endite with 2 short and 1 longer bristle. End joint with 13 ventral bristles and 2 hirsute posterior bristles (ventral bristles consisting of 6 medial bristles with long proximal and short distal spines, and 7 lateral bristles with long marginal hairs).

Seventh Limb (Figure 38b): Consisting of short stump.

Furca: Similar to that of adult female.

Rod-shaped Organ (Figure 38c): Elongate with rounded tip.

Eyes: Lateral eye with 4 ommatidia (Figure 38c,d); medial eye slightly larger than lateral eye, bare, pigmented (Figure 38c).

Copulatory Organ: Similar to that of adult male of Sarsiella neapolis Kornicker, 1974 (Figure 13j,k).

COMPARISONS.—The new species Sarsiella gomoiui is very closely related to S. neapolis and the appendages of both species are similar. The carapace of S. gomoiui differs from that of S. neapolis in having an additional ridge within the peripheral ridge common to both species. The additional ridge is sharply delimited on the 3 adult males of S. gomoiui in the collection, and is usually easily seen on adult females, but some early instars may be difficult to separate from early instars of S. neapolis. The ridges on the carapace of S. gomoiui resemble somewhat those of S. janiceae Kornicker, 1976b, but the endopodite of the female 2nd antenna of that species does not have a terminal bristle.