Eusarsiella saengeri Kornicker 1996

Eusarsiella saengeri

ETYMOLOGY.—Named for P. Saenger, Scientific Services Branch, Queensland Electricity Generating Board, Brisbane, Australia, from whom I received the specimens.

HOLOTYPE.—Undissected ovigerous female in alcohol, QM W20744.

TYPE LOCALITY.—Calliope River and Auckland Creek area near Gladstone, Queensland, Australia.

PARATYPES.—Type locality: USNM 157970A, adult female on slide and in alcohol; USNM 194120A, 1 undissected adult female in alcohol; USNM 194120B, partly dissected ovigerous female in alcohol.

DISTRIBUTION.—Collected only at type locality.

DESCRIPTION OF ADULT FEMALE (Figures 31–33).—Carapace oval in lateral view, with long slender posteroventral caudal process (Figure 31).

Ornamentation: Anterior, ventral, and dorsal margins scalloped; scallops larger along dorsal and posterodorsal margins; alate rib extending from anterior of valve at midheight to posterodorsal coner where it extends past valve edge (Figure 31); rib with slight curvature in vicinity of central adductor muscle attachments (Figure 31); posterior edge of valve between alate rib and caudal process with small triangular protuberance. Anterior and ventral margins with numerous slender bristles with bases along inner side of valve edge, some bristles broad at base or near midlength (Figure 32a,d); bristles extremely sparse elsewhere on valve surface. Valves without gel-like coating.

Infold: Anterior infold with minute bristle near valve midheight (Figure 32a). Infold of caudal process with 6–11 small spine-like bristles (Figure 32b–d); possible additional minute bristles near inner edge of infold in vicinity of caudal process but area indistinct on examined specimen; posterior infold with 2 setal bristles dorsal to caudal process (Figure 32b).

Carapace Size (length (L) with alate rib, height (H) with caudal process and dorsal scallops, in mm): QM W20744 (holotype), L = 1.77 (= 1.64 without alate rib), H = 1.57 (=1.51 without caudal process and with dorsal scallops), (= 1.27 without caudal process or dorsal scallops). USNM 157970A, separated left and right valves, L = 1.84, H = 1.59. USNM 194120A, L = 1.82, H = 1.52. USNM 194120B, L = 1.89, H = 1.59. Range of length including alate rib 1.77–1.89 mm.

First Antenna (Figure 32e): 1st joint bare. 2nd joint with dorsal bristle with short spines. 3rd joint fused to 4th; 3rd joint with 2 bristles (1 ventral, 1 dorsal) with short spines; 4th joint with 3 bristles (1 dorsal with short spines, 2 ventral bare). Ventral bristle of 5th joint long with minute terminal papilla (only proximal part of bristle shown). 6th joint fused to 5th, with short medial bristle near dorsal margin, bare except for slender subterminal hair. 7th joint: a-bristle slightly longer than bristle of 6th joint, bare except for long subterminal hair; b-bristle 3 times length of a-bristle, with minute terminal papilla; c-bristle same length as bristle of 5th joint, with 2 minute proximal filaments and minute terminal papilla (not shown). 8th joint (bristles not shown): d- and e-bristles very slightly shorter than c-bristle, bare with blunt tips; f-bristle same length as e-bristle, with minute terminal papilla; g-bristle slightly longer than e-bristle and slightly shorter than c-bristle, with 2 minute proximal filaments and minute terminal papilla. All bristles ringed (rings not shown).

Second Antenna: Protopodite bare (Figure 32f). Endopodite 1-jointed, with 2 proximal ringed anterior bristles (with few minute spines) and minute spine-like terminal bristle (Figure 32f). Exopodite: 1st joint with minute, terminal, medial, very slightly curved, tubular bristle; bristles of joints 2–8 with natatory hairs, no spines; 9th joint with 2 bristles (1 short dorsal, 1 long ventral) with natatory hairs; joints 2 to 6 or 7 with few minute spines along distal edges.

Mandible (Figure 33a): Coxale endite represented by small spine (not shown); coxale with long slender ventral spines (not shown). Basale: ventral margin with 6 small bristles (4 medial, 2 lateral); dorsal margin with 1 small spinous bristle just distal to midlength and 2 subterminal bristles (medial bristle unusually long). Exopodite absent. 1st endopodial joint with spines on medial surface and distally on ventral and dorsal margins and with stout ventral claw with narrow transparent flange (not shown) along proximal of dorsal margin (small part of flange near base of claw divided into row of minute spines). 2nd endopodial joint with small dorsal bristle and stout ventral claw with narrow transparent flange along proximal of ventral and dorsal margins. 3rd endopodial joint with stout terminal claw (without flanges) and 3 minute bristles (2 ventral, 1 dorsal).

Maxilla: Endites I and III each with 6 bristles (Figure 33b,d); endite II with 4 bristles (Figure 33c). Coxale with short dorsal bristle and dorsal fringe of long hairs (Figure 33e). Basale with short bristle near base of exopodite (Figure 33e). Exopodite with 3 bristles (1 long, 2 short). Endopodite: 1st joint with numerous fairly stout spines along anterior margin and spinous and pectinate alpha- and beta-bristles; 2nd joint with 2 small a-bristles, 1 small c-bristle, and 5 stout pectinate end bristles (middle bristle shorter; anterior bristle ringed distally).

Fifth Limb (Figure 33f): Epipodite with 36 hirsute bristles. Single endite with short bristle. Exopodite: 1st joint with 3 bristles; joints 2–5 fused, with total of 9 spinous bristles (interpretation: 2nd joint with 4 bristles (3 long terminal, 1 minute proximal); 3rd joint with 2 bristles (1 minute) on inner lobe and 1 on outer lobe; fused 4th and 5th joints with total of 2 bristles).

Sixth Limb (Figure 33g): Single endite with 2 or 3 bristles (1 or 2 short medial, 1 longer terminal). End joint with 15 spinous ringed bristles (rings not shown) followed by space and 2 broad plumose posterior bristles; medial side with rows of short spines on anterior part and long hairs on posterior part.

Seventh Limb: Proximal group with 13 bristles, 6 on one side, 7 on the other, each with 2 or 3 bells (mostly 3); terminal group with 6 bristles, 3 on each side, each with 2–5 bells; all bristles without marginal spines. Terminus with opposing combs.

Furca: Left lamella of USNM 157970A with 5 claws; claw 1 nonarticulated; claws decrease in length posteriorly along lamella (Figure 32h). Right lamella probably aberrant, with 6 claws and with 3rd claw more slender than 4th (Figure 32g). Each claw with long and short teeth along posterior edges; edge of lamella following claws with several spines.

Bellonci Organ: Short, cone-like (Figure 33j,k). Organ of USNM 157970A possibly aberrant, with long tapering proximal part (Figure 33i).

Eyes: Medial eye with anterior area of brown pigment (Figure 33i–k). Lateral eye small, with 4 or 5 ommatidia and slight amount of brown pigment (Figure 33h,j,k).

Upper Lip (Figure 32j): Single lobe with few hairs at posteroventral corner.

Genitalia: Not observed.

Posterior of Body (Figure 32i): Evenly rounded, bare.

Y-Sclerite (Figure 32i): Typical for subfamily except more elongate.

Number of Eggs: QM W20744 (holotype) with about 10 eggs in marsupium (observed through shell); length of 1 egg 0.204 mm. USNM 194120B with 11 eggs in marsupium and with smaller unextruded eggs; length of 1 extruded egg 0.238 mm. USNM 157970A with small unextruded eggs (Figure 32i).

Gut Content: USNM 157970A with 4 harpacticoid copepods (identified by T.E. Bowman, Smithsonian Institution) and 1 nematode (identified by D. Hope, Smithsonian Institution) in gut.

COMPARISONS.—The carapace of E. saengeri resembles that of E. serrata (Hall, 1987) in that both have an alate process, but the marginal serrations along the edges of the valves appear more prominent in E. saengeri than in E. serrata; also, E. serrata has only seven proximal bristles rather than 13 on the seventh limb, and the exopodite of the maxilla has two bristles rather than three.