Eusarsiella syrinx, Kornicker & Iliffe & Harrison-Nelson, 2007

Kornicker, Louis S., Iliffe, Thomas M. & Harrison-Nelson, Elizabeth, 2007, Ostracoda (Myodocopa) from Anchialine Caves and Ocean Blue Holes, Zootaxa 1565 (1), pp. 1-151 : 97-118

Eusarsiella syrinx , new species

Figs. 25, 25 , 53–56 a,b ; 57–63 , Table 13

Etymology. From the Greek syrinx (pipe).

Holotype. USNM 1021463 , undissected ovigerous female in alcohol.

Type locality. Sta 00-019, Mystery Cave, Stocking Island , Exuma Cays, Great Bahama Bank .

Paratypes. USNM 1021464 , adult male on 2 slides and in alcohol . USNM 1021465 , adult female on 2 slides and in alcohol . USNM 1021466 , instar IV (A-1) female on slide and in alcohol . USNM 1021467 , Instar III (A-2) (sex unknown) on slide and in alcohol. USNM 1021468 , instar II (A-3) (sex unknown) on slide and in alcohol. USNM 1021469 , instar I (A-4) (sex unknown) on slide and in alcohol . USNM 1021470 instar I (A- 4) (sex unknown) undissected specimen in alcohol .

*Percentages were calculated by subtracting the number of bristles and claws in one stage from the number in the following stage, then dividing the difference by the number in the first stage and multiplying by 100.

**Percentages were calculated by dividing the number of bristles and claws between successive stages by the total number obtained by subtracting the number on instar I from the number on the adult female and then multiplying by 100.

***Percentages were calculated by dividing the number of bristles and claws on each stage by the number on the adult female and then multiplying by 100.

Distribution. Type locality.

Morphometrics. Morphometrics of appendages of different growth stages are shown in Figs. 25 , 26 and Table 13.

Description of adult male ( Figs. 53–56 a,b ). Carapace elongate with incisure forming right angle ( Fig. 53 ). Surface with two lateral ribs connected posteriorly by vertical ridge. Horizontal ridge present between lower rib and ventral margin of valve. Small spinous process near posterodorsal corner of valve connected by 2 rows of small bristles to posterior end of upper horizontal rib. Rostrum formed by process extending anteri-

orly past anterior edge of valve ( Fig. 54 a–c ). Caudal process in lateral view forming a 45° angle.

Ornamentation ( Figs. 53 , 54 c ): Surface with shallow round fossae and numerous small single spine-like bristles; bristles mostly between fossae and not restricted to edges of fossae; not more than 8 bristles along edges of fossae. Bristles along ribs, ridges, edges of valves, and near rostrum and caudal process longer and more numerous than those on other surfaces of valves. Few long bristles with broad bases scattered over valve surface. Transparent gel-like substance visible filling space between bristles on ribs, ridges, and valve edges.

Infold: Anterior infold with single small bristle ventral to rostrum ( Fig. 54 a ). Infold of caudal process with proximal vertical row of 3 small bare bristles and two smaller bristles along inner edge ( Fig. 54 b ); posterior infold with 2 setal bristles

Selvage: Narrow selvage with smooth outer edge undivided at incisure

Central adductor muscle attachments: Many small oval attachments (some attachments darkened in Fig. 53 ).

Carapace size (length, height in mm): USNM 1021464, length with caudal process 0.98, length without caudal process 0.87, height 0.59.

First antenna ( Fig. 54 d,e ): 1st segment bare. 2nd segment with minute dorsal spine near midlength and bare distal dorsal bristle. 3rd and 4th segments fused; 3rd segment with 2 bristles (1 ventral (small with terminal spine), 1 bare dorsal). 4th segment with 2 bare bristles (1 ventral, 1 dorsal). 5th segment small and wedged ventrally between 4th and 6th segments; sensory bristle with abundant thin filaments and stem with 4 short filaments. 6th segment with short bare medial bristle. 7th segment: a-bristle bare, short; b-bristle medial short, bare. 8th segment: c-bristle long with 4 short marginal filaments, d- and e-bristles long, bare; f-bristle shorter than c-bristle, with 2 short marginal filaments; g-bristle as long as c-bristle, with 5 marginal filaments.

Second antenna: Protopod bare ( Fig. 55 k ). Endopod not reflexed, with 2 segments ( Fig. 54 f ): 1st segment with 1 short ringed proximal bristle; 2nd segment with two short ringed terminal bristles. Exopod ( Fig. 54 g ): 1st segment with minute medial spine on distal margin (not shown); bristles of segments 2 and 3 with proximal ventral spines, few proximal dorsal hairs, and distal natatory hairs, bristles of segments 4–8 with natatory hairs and very few ventral spines; 9th segment with 2 bristles (1 small bare dorsal, other long with natatory hairs); segments 2–8 with minute indistinct spines forming row along distal lateral margins.

Mandible ( Figs. 55 a , 56 a,b ): Coxa endite consisting of short spine. Basis: with 5 proximal bristles on or near ventral margin, 1 medial bristle near midlength, and 3 dorsal bristles (2 long, 1 shorter). Exopod consisting of small blunt process. Endopod: 1st segment with 2 ventral terminal bristles (longest with long marginal hairs), 1 subterminal dorsal short bristle-like spine, and numerous medial spines. 2nd segment: ventral margin with 1 or 2 small terminal spine-like bristles and 1 short ringed bristle; dorsal margin with 1 long slender dor- sal bristle at midlength, and medial spines along distal edge. 3rd segment with long stout terminal claw with small teeth along ventral margin (medial and lateral row), and 2 small ventral bristles.

Maxilla ( Fig. 55 b ): Reduced. Coxa hirsute. Exopod with 2 stout ringed bristles. Bristles of endites, basis, and endopod indistinct, with total of at least 20 bristles. Remaining bristles indistinct

Fifth limb ( Fig. 55 c ): Coxa endite with 1 short bristle. Basis: endite I lobate with 2 bristles; endite II with 3 bristles. Endopod: 1st segment with 3 bristles; 2nd segment with 2 bristles. Exopod represented by 1 bristle. Epipod fragmented, with about 36 plumose bristles.

Sixth limb ( Fig. 55 d ): Single endite with 3 small bristles. End segment with bristles forming 2 rows: medial row of 5 bristles with short spines, and 8 lateral bristles with long spines; posterior edge with distal spines and 2 stout plumose bristles immediately adjacent to posterior ventral bristle.

Seventh limb ( Fig. 55 e,f ): Limb long with about 54 well defined segments. Terminal group with 4 bristles, 2 on each side, each bristle with 6 or 7 bells and no marginal spines. Terminus slightly convex, bare.

Furca ( Fig. 55 g ): Each lamella with 5 claws; claw 1 fused to lamella, claws 2–5 separated from lamella by suture. All claws with teeth along posterior edges and indistinct spines along part of anterior edges. Left lamella with spines along lamella following claws.

Bellonci Organ ( Fig. 54 h ): Elongate with broadly rounded tip.

Eyes: Lateral eye smaller than medial eye, with 5 or 6 ommatidia; eye amber colored ( Fig. 55 k ). Medial eye bare, brown ( Fig. 55 k ).

Posterior of body: Evenly rounded, bare.

Genitalia ( Fig. 55 g,h ): Lobate copulatory organ on each side of body anterior to furca; distal lobe with sclerotized curved tooth and 2 or 3 short bristles. All lobes with few short bristles.

Y-Sclerite ( Fig. 55 i ) and Girdle ( Fig. 55 i,j ): Y-Sclerite branching distally and posterior tip with rightangle. Girdle forming one arch-shaped sclerite.

Gut content: Unrecognizable particulate matter.

Description of adult female ( Figs. 57–60 ). Carapace oval in lateral view with long tapered backward- pointing caudal process and without incisure ( Fig. 57 ). Surface with 2 lateral ribs connected posteriorly by diagonal rib terminating posteriorly with backward-pointing spinous node. Upper lateral rib with 6 nodes, 5 of these with long terminal bristle. Lower lateral rib with 6 nodes, 5 of these with long terminal bristle. Row of 3 long bristles present near anterior part of shell between the 2 ribs. Row of 3 nodes bearing 1 or 2 long terminal bristles present between lower rib and ventral margin of valve; 1 node with long terminal bristle present near anterior end of caudal process. Outer edge of valve with 16 nodes bearing 1 or 2 long bristles. All nodes and ribs covered with small bristles with knobby tips.

Ornamentation ( Figs. 57 , 58 ): Surface with shallow oval fossae with bare bottoms. Scattered small bristles with knobby tips present between fossae and on ribs and nodes ( Fig. 58 b ). Anterior and ventral margins with long bristles with broad section at distal two-thirds and pointed tips, and shorter slenderer bristles with pointed tips (these medial to the long bristles). Tip of caudal process with 2 bristles (1 near dorsal end, 1 near ventral end) with 4 shorter bristles between them. Valve including ribs and nodes coated with transparent gellike substance filling space between the short bristles.

Infold: Anterior infold with small bristle near midheight ( Fig. 58 f ). Infold of caudal process with vertical row of 4 to 6 bristles and 2 small bristles near inner margin of infold ( Fig. 58 e ). Posterior infold with 2 setal bristle ventral to midheight.

Selvage: Lamellar prolongation extending well past tip of caudal process. Lamellar prolongation broad along anterior and ventral margins and with smooth outer edge.

Central adductor muscle attachments: Each valve with 10 or 11 oval attachments ( Figs. 57 , 58 a ).

Carapace size (length, height in mm): USNM 1021465, length with caudal process 1.57, length without caudal process 1.35, height 1.18. USNM 1021463, length with caudal process 1.54, length between anterior edge and tip of posterior node, 1.48, length without caudal process or posterior node, 1.37, height 1,19.

First antenna ( Fig. 59 a,b ): 1st segment bare. 2nd with minute dorsal spine near midlength and bare distal dorsal bristle. 3rd and 4th segments fused; 3rd with 2 terminal bristles (1 ventral, 1 dorsal); 4th segment with 3 or 4 terminal bristles (2 ventral, 1 or 2 dorsal). 5th segment with long sensory bristle with 4 minute marginal filaments. 6th segment with short medial bristle. 7th segment: a-bristle short with indistinct marginal spines; b-bristle about same length as a-bristle, bare; c-bristle about same length as bristle of 5th segment, with 2 minute marginal filaments. 8th segment: d- and e-bristles shorter than bristle of 5th segment, bare with blunt tips; f-bristle about same length as d-bristle, with 4 minute marginal filaments; g-bristle as long as bristle of 5th segment, with 2 minute marginal filaments; b-, c-, f, and g-bristles with terminal spine.

Second antenna ( Fig. 59 b–d ): Protopodite bare ( Fig. 59 b,d ). Endopod with 1 segment with 2 ringed anterior bristles and short unringed terminal bristle ( Fig. 59 c,d ). Exopod: 1st segment with short medial recurved spine ( Fig. 59d ); bristles of segments 2–8 with stout proximal ventral spines and distal natatory hairs; 9th segment with 2 bristles (1 small bare (dorsal), 1 long with proximal ventral spines and distal natatory hairs.)

Mandible ( Fig. 59 e–g ): Ventral part of precoxa adjacent to coxa with brown pigment in transmitted light (reddish in reflected light). Coxa endite consisting of short stout spine; ventral margin of coxa with short hairs. Basis with 3 medial bristles (shorter bristle closer to ventral edge); dorsal margin with 2 minute bristles (1 distal to midlength, 1 terminal). Exopod absent. Endopod: 1st segment with 38 to 47 distal medial spines, row of minute medial spines near distal margin (row extends to posterior edge of segment), and 2 minute medial spines near base of stout ventral claw; ventral claw with proximal row of minute teeth along dorsal edge. 2nd segment with minute dorsal spine-like bristle and stout ventral claw. 3rd segment with 2 minute bristles (1 ventral, 1 dorsal) and stout terminal claw.

Maxilla ( Fig. 60 a,b ): Endite I with 6 bristles; endite II with 4 bristles; endite III with 6 bristles ( Fig. 60 b ). Coxa with short dorsal bristle ( Fig. 60 a ). 1 small bristle on basis near exopod. Exopod with 2 bristles. Endopod: 1st segment with spinous alpha- and beta-bristles. 2nd segment with 2 lateral a-bristles, 1 medial c-bristle, and 5 pectinate terminal bristles; 4th terminal bristle from anterior end longer than others.

Fifth limb ( Fig. 60 c ): Epipod with 35 plumose bristles. Coxa endite with 1 short bristle. Basis with 2 endites: endite I lobate with 2 bristles; endite II with 4 bristles. Endopod with 2 fused segments: segment 1 with 3 bristles (1 short); segment 2 with 2 bristles. Exopod represented by 1 short bristle. Limb hirsute.

Sixth limb ( Fig. 60 d ): Single endite with 3 bristles. End segment with 12 bristles (5 medial, 7 lateral) separated by space from 2 posterior plumose bristles

Seventh limb ( Fig. 60 e,f ): Each limb with 2 proximal bristles, each with 5 bells, and 6 terminal bristles, each with 3 to 7 bells; distal 15 segments proximal to terminus slightly broader than proximal segments, each with sclerotized midline, and a small amber colored round cell near outer edge ( Fig. 60 f ). Terminus with opposing teeth (2 or 3 on each side (exact number difficult to resolve)). Bristles without marginal spines.

Bellonci Organ: Lost. Elongate with rounded tip based on organ of A- 1 female shown in Fig. 61 l .

Furca ( Fig. 60 g ): Each lamella with 5 claws; lamella following claws of left side with numerous spines; only few spines on right lamella. Claws 1 to 4 with teeth along posterior edges; claw 1 with 3 or 4 stouter teeth near midlength; tips of claws pointed. Right lamella anterior to left by width of claw 1, and with few minute spines along anterior edge near base of claw.

Eyes ( Fig. 59 b ): Lateral eyes small, each with 5 amber-colored ommatidia. Medial eye larger than lateral eye.

Genitalia: Small oval amber-colored area present anterior to Y-sclerite, but it may not be genitalia.

Y-Sclerite ( Fig. 60 h ): With usual ventral branch.

Posterior of body: Evenly rounded, bare.

Gut content: USNM 1021465 with 1 rotaloid foraminiferan in posterior end of gut.

Eggs: USNM 1021463 with 4 eggs in marsupium; length of 1 egg 0.22 mm .

Description of instar IV (A-1) female ( Fig. 61 ). Shape of carapace in lateral view differs from that of adult female in having an oblique posterior margin ( Fig. 61 a ).

Ornamentation ( Fig. 61 a,b ): Carapace without parallel ribs present on carapace of adult female and with fewer nodes. Surface with shallow round fossae; except for those near middle of valve, fossae appear as crescents open to valve margin. Surface between fossae with small bristles with knobbed tips ( Fig. 61 b ). Tip of caudal process with 2 bristles (1 at ventral end, 1 near dorsal end) and few shorter bristles between them.

Infold: Anterior infold with small bristle near midheight. Infold of caudal process with vertical row of 4 or 5 bristles and 2 small bristles near inner margin of infold ( Fig. 61 e ). Posterior infold with 2 setal bristles ventral to midheight.

Selvage: Narrow selvage with smooth outer edge undivided at incisure and extending past tip of caudal process.

Central adductor muscle attachments ( Fig. 61 a,c,d ): With 16 to 18 ovoid attachments.

Carapace size (length, height in mm): USNM 1021466, length with caudal process 1.30, length without caudal process 1.14, length from anterior edge to posterior end of posterior node 0.81, height 1.10.

First antenna ( Fig. 61 f ): 1st segment bare. 2nd with minute dorsal spine near midlength and distal dorsal bristle with few indistinct marginal spines. 3rd and 4th segments fused; 3rd with 2 terminal bristles (1 ventral, 1 dorsal); 4th segment with 3 bristles (2 ventral, 1 dorsal). Long ventral bristle of 5th segment with 2 minute marginal filaments. 6th segment with short bare medial bristle. 7th segment: a-bristle bare, about same length as 5th segment; b-bristle same length as a-bristle; c-bristle same length as bristle of 5th segment, with 2 minute marginal filaments. 8th segment: d- and e-bristles shorter than c-bristle, bare with blunt tips; f-bristle shorter than c-bristle, about same length as d-bristle, with 1 minute proximal filament; g-bristle about same length as c-bristle, with 4 minute marginal filaments (2 proximal filaments longer than others). b-, c-, f-, and g-bristles with terminal spine.

Second antenna: Protopod and exopod (including number of bristles and their spination) similar to those of adult female. Endopod with single segment with 2 ringed anterior bristles and short unringed terminal bristle ( Fig. 61 g ).

Mandible: Basis with 3 medial bristles (shortest closer to ventral margin). Limb otherwise similar to that of adult female. Ventral area of precoxa just adjacent to coxa with brown pigment.

Maxilla ( Fig. 61 h ): Endite I with 6 bristles; endite II with 4 bristles; endite III with 6 bristles similar to those of adult female. Coxa, basis, endopod, and exopod similar to those of adult female.

Fifth limb: Epipod with 36 plumose bristles. Coxa endite with 1 short bristle. Basis with 2 endites: endite I with 2 bristles; endite II with 3 bristles. Endopod with 2 fused segments: segment 1 with 3 bristles (2 long, 1 short); segment 2 with 2 long bristles. Exopod represented by 1 short bristle.

Sixth limb: Single endite with 3 bristles (2 short medial, 1 longer terminal); end segment with 12 bristles (6 lateral, 6 medial) followed by 2 posterior plumose bristle.

Seventh limb ( Fig. 61 i,j ): Each limb with 2 proximal tapered bristles, each with 3 bells, and 4 terminal tapered bristles, each with 4 bells. Terminus with minute opposing teeth (1 or 2 on each side).

Bellonci Organ ( Fig. 61 l ): Elongate with rounded tip.

Furca ( Fig. 61 k ): Each lamella with 5 claws similar to those of adult female. Anterior claw of right lamella anterior to anterior claw of left lamella by width of base of claw 1. Lamella following right claw with 2 fairly stout spines, that of left claw with 5 fairly stout spines.

Eyes ( Fig. 61 l ): Lateral eye small with 5 amber colored ommatidia. Medial eye larger than lateral eye, bare, light amber in color.

Upper lip ( Fig. 61 m ): With projecting rounded tooth-like tip.

Genitalia: Absent.

Y-Sclerite ( Fig. 61 k ): With usual ventral branch.

Posterior of body: Evenly rounded, bare.

Gut content: With unrecognizable amber colored particles.

Eggs: Absent.

Description of instar III (A-2) (sex unknown) ( Fig. 62 ). Shape of carapace in lateral view similar to that of instar IV female ( Fig. 62 a ). Valves including nodes coated with transparent gel-like substance filling space between the short bristles.

Ornamentation ( Fig. 62 a ): Ribs absent. Nodes, in general, similar to those of instar IV female, less developed than those of adult female. Fossae of USNM 1021458 more distinct than those of instar IV female and adult female described above; many fossae rectangular making surface of valves appear reticulate. Surface with many long bristles distributed, in general, in same manner as in instar IV female. Surface between fossae with minute bristles with knobby tips.

Infold: Anterior infold with small bristle near midheight. Infold of caudal process with vertical row of 3 bristles and 1 or 2 small bristles near inner margin of infold. Posterior infold with 2 setal bristles ventral to midheight.

Selvage: Lamellar prolongation extending well past tip of caudal process. Lamellar prolongation broad along anterior and ventral margins and with smooth outer edge.

Central adductor muscle attachments ( Fig. 62 b ): Each valve with about 13 oval attachments.

Carapace size (length, height in mm): USNM 1021467, length including caudal process 1.02, length excluding caudal process 0.85, length from tip of posterior node to anterior margin of valve 0.81, height 0.69.

First antenna ( Fig. 62 c ): 1st segment bare. 2nd with minute dorsal spine near midlength and distal dorsal bristle. 3rd and 4th segments fused; 3rd with 2 bristles (1 ventral, 1 dorsal); 4th with 2 bristles (1 ventral, 1 dorsal). 5th segment with long bristle with 3 minute filaments. 6th segment with small medial bristle. 7th segment: a-bristle short; b-bristle about same length as a-bristle; c-bristle about same length as bristle of 5th segment, with 3 minute marginal filaments. 8th segment: d- and e-bristles longer than b-bristle, bare with blunt tips; f-bristle shorter than c-bristle, with 1 minute marginal filament; g-bristle as long as c-bristle, with 4 small marginal filaments (2 proximal filaments longer than others).

Second antenna: Protopod, exopod, and endopod ( Fig. 62 d ) similar to those of both instar IV and adult female.

Mandible ( Fig. 62 e ): Coxa, endopod similar to those of both instar IV and adult female. Basis with 3 medial bristles (shortest closer to ventral margin) and 2 minute dorsal bristles (1 distal to midlength, 1 terminal). Ventral area of precoxa adjacent to coxa with brown pigment in transmitted light similar to area observed on instar IV female.

Maxilla: Endites I, II, and III, coxa, basis, endopod, and exopod with similar number of bristles present on both instar IV and adult female.

Fifth limb ( Fig. 62 f ): Epipod with 31 plumose bristles. Single endite with 1 bristle. Basis with 2 endites: endite I with 2 bristles; endite II with 3 bristles. Endopod with 2 fused segments: segment 1 with 3 bristles (2 long, 1 short); segment 2 with 2 long bristles. Exopod represented by short bristle.

Sixth limb: Single endite with 2 bristles (1 terminal, 1 shorter proximal); end segment with 10 or 11 bristles separated by space from 2 plumose posterior bristles.

Seventh limb ( Fig. 62 g ): Elongate, without rings, bare.

Furca: With 5 claws similar to those of both instar IV and adult female. Spines following claws on lamella. Positions of left and right lamella relative to each other similar to those of both instar IV and adult female.

Bellonci Organ ( Fig. 62 h ): Elongate with broad rounded tip.

Eyes ( Fig. 62 h ): Lateral eye with 5 amber-colored ommatidia. Medial eye slightly larger than lateral eye, amber-colored.

Posterior of body: Evenly rounded, bare.

Genitalia: Absent.

Y-Sclerite: With ventral branch.

Gut content: Posterior gut empty. Inner face of posterior gut lobate.

Eggs: None.

Description of instar II (A-3) (sex unknown) ( Fig. 63 ). Carapace similar in shape to that of the instar III instar ( Fig. 63 a ). Ribs absent, nodes few and small.

Ornamentation ( Fig. 63 a ): Surface with shallow round fossae (only few shown in Fig. 63 a ). Surface between fossae with short bristles with knobby tips. Few long bristles with broad bases on valve surface. Long bristles present along anterior and ventral margins. Tip of caudal process with 2 bristles (1 near dorsal end, 1 near ventral end). Transparent gel-like substance visible filling space between bristles and along valve edges.

Infold: Anterior infold with small bristle near midheight. Infold of caudal process with 2 or 3 bristles near anterior end and 2 minute bristles near inner margin of infold. Posterior infold with 2 setal bristles near midheight.

Selvage: Lamellar prolongation extending well past tip of caudal process.

Central adductor muscle attachments ( Fig. 63 b ): About 11 closely oval attachments visible.

Carapace size (length, height in mm): USNM 1021468, length with caudal process 0.83 mm, length without caudal process 0.72, height 0.60.

First antenna ( Fig. 63 c ): 1st segment bare. 2nd segment with minute dorsal spine at midlength and short distal dorsal bristle. 3rd segment fused to 4th; 3rd segment with 2 bristles (1 ventral, 1 dorsal); 4th segment with dorsal bristle reaching middle of 5th segment. 5th segment with long ventral bristle with 2 minute proximal filaments. 6th segment with short medial bristle. 7th segment: a-bristle short; b-bristle about same length as a-bristle; c-bristle same length as bristle of 5th segment, with 2 minute marginal filaments. 8th segment: d- and e-bristle shorter than c-bristle, bare with blunt tips; f-bristle slightly shorter than d- and e-bristles, with minute proximal marginal filament; g-bristle as long as c-bristle, with 2 small proximal marginal filaments.

Second antenna: Protopod bare. Exopod similar to that of instar III, with bent terminal spine-like medial bristle on 1st segment and 2 bristles on 9th segment ( Fig. 63 e ). Endopod with single segment with short prox- imal ringed anterior bristle and small unringed terminal bristle on small node (node could be interpreted to be 2nd segment) ( Fig. 63 d ).

Mandible ( Fig. 63 f ): Precoxa with brown pigment at ventral margin adjacent to coxa. Coxa endite consisting of short stout spine; ventral margin of coxa with short hairs. Basis: medial surface near ventral margin with 3 bristles (shortest bristle closer to ventral margin); dorsal margin with 1 minute spine-like bristle distal to midlength and similar bristle subterminal. Endopod similar to that of instar III.

Maxilla: Coxa, basis, endopod, and exopod similar to that of A- 2 female. Endite I with 6 bristles; endite II with 4 bristles; endite III with 6 bristles similar to those of adult female .

Fifth limb ( Fig. 63 g ): Epipod with about 30 bristles. Coxa endite with 1 short bristle. Basis with 2 endites: Endite I lobate with 2 or 3 bristles; endite II with 3 bristles. Endopod with 2 segments: segment 1 with 3 bristles; segment II with 2 bristles. Exopod represented by 1 short bristle.

Sixth limb ( Fig. 63 h ): Lobate with 1 bristle near midwidth; margin of limb hirsute.

Seventh limb: Short, bare.

Furca: Each lamella with 5 claws similar to those of instar III. Spines on lamellae following claws similar to those of instar III. Right lamella anterior to left by width of base of claw 1.

Bellonci Organ ( Fig. 63 i ): Elongate with broadly rounded tip

Eyes: Lateral eye with 5 amber-colored ommatidia ( Fig. 63 j ). Medial eye larger than lateral eye, light brown in color ( Fig. 63 i ).

Posterior of body: Evenly rounded, bare.

Genitalia: absent.

Y-Sclerite: With ventral branch.

Gut content: Unrecognizable particulate matter.

Description of instar I (A-4) instar (sex unknown) ( Figs. 64 , 65 ). Carapace similar in shape to that of Instar II instar. Ribs and nodes absent. Surface with scattered long bristles and numerous small bristles with knobby tips. Anterior and ventral margins with numerous long bristles. Surface coated with transparent gellike substance filling space between short bristles.

Ornamentation ( Fig. 64 a ): Surface with weakly developed oval fossae with bare bottoms. Surface between fossae with scattered long bristles and numerous short bristles with knobby tips. Anterior and ventral margins with long and medium length bristles with pointed tips. Tip of caudal process with 2 bristles (1 near ventral end, 1 near dorsal end) and smaller bristles between them.

Infold: Anterior infold with small bristle near midheight. Selvage of caudal process with none (left valve) or 1 small bristle (right valve) near anterior end and 2 small bristles at inner edge of infold. Posterior infold with 1 setal bristle ventral to midheight.

Selvage: Lamellar prolongation of selvage extending well past tip of caudal process. Lamellar prolongation broad along anterior and ventral margins and with smooth outer edge.

Central adductor muscle attachments ( Fig. 64 a,b ): USNM 1021469 with about 20 muscle that appeared as jumbled mass when viewed through shell. Individual muscles not forming tight bundle usually extending from valve to valve in myodocopids. Muscles in USNM 1021470 appear of normal tightly bundled type when viewed through valves (valves not opened) .

Carapace size (length, height in mm): USNM 1021469, length with caudal process 0.68, length without caudal process 0.59, height 0.48. USNM 1021470, length with caudal process 0.66, length without caudal process 0.56, height 0.46.

First antenna ( Fig. 64 c ): 1st segment bare. 2nd segments with minute distal dorsal spine (in about same location as bristle on later stages). 3rd and 4th segments fused; segment 3 with 2 bristles (1 ventral, 1 dorsal); segment 4 bare. 5th segment with long ventral bristle. 6th segment with small medial bristle. 7th segment: abristle 2 or 3 times length of bristle of 6th segment; b-bristle about same length as a-bristle; c-bristle about same length as bristle of 5th segment. 8th segment: d- and e-bristles only slightly shorter than c-bristle; f-bristle shorter than d-bristle; g-bristle about same length as c-bristle. Bristle of 5th segment and c-, f-, and g-bristles without marginal filaments.

Second antenna ( Fig. 64 d,e ): Protopod and exopod similar to those of instar II, 9th segment with 2 bristles (1 long, 1 short). Endopod with 1 segment with minute terminal spine-like bristle ( Fig. 64 e ).

Mandible ( Fig. 64 f,g ): Coxa and endopod similar to those of instar II. Ventral part of precoxa adjacent to coxa without brown color. Basis: medial surface with 3 bristles (shortest bristle closer to ventral margin); dorsal margin with 2 distal minute spine-like bristles.

Maxilla ( Figs. 64 h–j , 65 a ): Coxa, basis, and exopod similar to those of instar II. Endopod: 1st segment with alpha- and beta-bristle; 2nd segment with 2 a-bristles, 1 c-bristle, and 3 end bristles. Endite I with 6 bristles; endite II with 4 bristles; endite III with 4 bristles (2 anterior, 2 posterior).

Fifth limb ( Fig. 65 b ): Epipod with 25 plumose bristles. Coxa endite with 1 short bristle. Basis with 2 endites: endite I with 2 bristles, endite 2 with 3 bristles. Endopod with 2 segments: segment 1 with 3 bristles, segment 2 with 2 bristles. Exopod with 1 short bristle. Limb hirsute.

Sixth limb ( Fig. 65 c ): Hirsute, without bristles.

Seventh limb ( Fig. 65 d,g ): Minute indistinct bare lobe.

Furca ( Fig. 65 e,f ): Each lamella with 3 claws; claws 1 and 3 fused to lamella. Claw 1 with few stout teeth and numerous small teeth (teeth proximal to midlength longer and stouter than those distal to midlength); claw 2 with small teeth and few slightly longer teeth; claw 3 with few small teeth. Lamellae following claws with spines. Long medial hairs forming row at base of claw 1. Few long medial spines proximal to claw 3. Right lamella anterior to left by width of base of claw 1.

Bellonci Organ ( Fig. 64 k ): Short with broadly rounded tip.

Eyes: Lateral eye with 5 amber-colored ommatidia ( Fig. 64 l ). Medial eye larger than lateral eye, with brown color ( Fig. 64 k ).

Upper lip ( Fig. 64 f ): Broadly rounded with small lateral process at tip.

Posterior of body: Evenly rounded, bare.

Genitalia: Absent.

Y-Sclerite: With ventral branch ( Fig. 65 g ). Girdle weakly developed ( Fig. 65 g ).

Gut content: Unidentified particulate matter.

Remarks. The adult male, adult females and juveniles referred to this species were collected in the same sample. The adult male and female of many sarsiellids differ considerably in morphology of both the carapace and appendages, and one cannot always with certainty refer them to the same species. The referral here is supported by the morphology of the short bristles covering the carapaces of both the male and female. The bristles have a knobby tip on both the male and female, and the locations of the bristles relative to the shallow fossae are similar on both the adult male and female. The knobby tip is smaller on the adult male than on the adult female. The knobby bristles are also present on juveniles. The small knobby tips are seen best when the valve is viewed at high magnification (40X or 100X objective) and preferably with the valve under a cover slip. A few early instars of sarsiellids in the sample, which do not have bristles with knobby tips, are referred to Eusarsiella sp. indet.

Comparisons. Male: The valves of the male E. syrinx differ from those of the adult male E. ryanae Kornicker & Iliffe 2000 in having a less elongate caudal process and less abundant short spine-like bristles, especially along edges of fossae and, also, fewer bristles on the infold of the caudal process (three compared to six or seven). The endopod of the second antenna of E. syrinx bears one bristle on the first segment compared to two bristles on E. ryanae . The first antenna of E. syrinx bears one ventral bristle on the fourth segment compared to two bristles on E. ryanae . The exopod of mandible of E. syrinx is a short bare blunt process, whereas that of E. ryanae is longer and spinous. The second segment of the endopod of the second antenna of E. syrinx is much longer than that of E. warneri Kornicker et al. 2002 . The exopod of the mandible of E. syrinx is a short blunt process, whereas that of E. warneri is a small bristle ( Fig. 56 c ). Parts of the mandible of E. warneri and E. syrinx are compared in Fig. 56. E . syrinx differs from the adult male designated Eusarsiella sp. X by Kornicker et al. (2002: 63) in having both no proximal bristles on the seventh limb and a second segment on the endopod of the second antenna (see Kornicker 1958: figs. 74 c, 75 c). The mandible of the adult male E. syrinx differs from that of the adult male E. styx Kornicker & Iliffe 1989b , in having a smaller and bare exopod and a longer terminal claw on the third endopod segment.

Female: The carapace of E. syrinx differs from that of E. ryanae in that the short bristles on the outer surface have knobby rather than pointed tips and in the carapace having many more nodes. The first antennae of E. capillaris ( Kornicker 1958) and Eusarsiella sp. X (Kornicker et al. 2002: 63) differ from those of E. syrinx in not having a dorsal bristle on the first segment. The carapace of E. syrinx is much larger than that of E. cornuta Poulsen 1965 , and the endopod of the second antenna of the former bears a terminal bristle absent on the latter. The precoxa of the mandible of the adult female and instars II to IV of E. syrinx have ventrally adjacent to the coxa a brown or reddish brown area not described in previous sarsiellids. However, its presence on other species may not have been sufficiently noticed to be included in their descriptions. The basis of the mandible of E. syrinx bears three bristles near the ventral margin compared to six on E. ryanae . In the “Key to the Species of Eusarsiella ” in Kornicker (1986:44–47) which includes 35 species from the West Atlantic and Gulf of Mexico, the female E. syrinx keys out to Eusarsiella cornuta Poulsen 1965 . The carapace of E. cornuta differs from that of E. syrinx in lacking projecting processes along the outer margin. The carapaces of two species described from Bermuda, Eusarsiella absens ( Kornicker 1981) and Eusarsiella styx Kornicker & Iliffe 1989b , differ from that of E. syrinx in lacking projecting processes along the margins.

Ontogeny and Sexual Dimorphism ( Table 13, Figs. 25 , 26 ). Carapace: Posterior margins of instars in lateral view are oblique, whereas the margin of the adult female is vertical. The posterodorsal part of the carapace of the adult female is broader than on instars, no doubt to accommodate eggs. The carapace of the adult male differs from those of instars and the adult female mainly in having a prominent rostrum.

Ornamentation: Adults have prominent ribs which are absent on instars. Prominent nodes on the adults progressively become less prominent in younger instars. Visibility of fossae is in part a function of preservation, because they are quite apparent on an instar II (USNM 1021467 but are less apparent on other instars. They are quite visible on both adult females in the collection. The number and distribution of long bristles appear similar in the adult female and instars. Short bristles with knobbed tips are present on all specimens.

Infold: The anterior infold of instars and adult bear a small bristle near midheight. The adult female caudal process bears 4 to 6 bristles forming vertical row; the numbers decrease in progressively younger instars, and none are present on instar I. A broad infold is present at all stages.

Selvage: A broad lamellar prolongation with a smooth outer margin is present on all stages. It extends well past the posterior end of the caudal process and is undivided at the anterior margin of valves.

Central adductor muscle attachments: The number of muscle attachments given herein is those seen through the outside of each valve, and the differences observed for the stages are in large part the result of their being partly obscured on some specimens. In one of the first instars (USNM 1021469) the individual muscle strands are loosely packed ( Fig. 64 b ), but in the second instar I (USNM 1021470) in the collection the strands are tightly bound together, as is normal for myodocopids.

Carapace size: Growth factors based on total length including the caudal process for the few specimens in the collection are: Instar I to instar II, 1.24; II to III, 1.23; II to IV, 1.27; IV to adult female, 1.30; and IV to adult male, 0.75.

First antenna: The 3rd and 4th segments are fused in all stages. The 5th segment is wedged ventrally between the 4th and 6th segments in the adult male. The 6th segment is well developed only in the adult male; in other stages the segment is fused to the 5th segment and, at most, consists of a narrow band. Segment 2 is without a dorsal bristle on instar I, and bears 1 dorsal bristle on later stages. Segment 4 is without bristles on instar I, bears 1 dorsal bristle on instar II, 1 ventral and 1 dorsal bristle on instar III as well as on the adult male, and 2 ventral and 2 dorsal bristles on remaining stages. The ventral bristle of the 5th segment is without marginal filaments on instar I and bears numerous long marginal filaments on the adult male; on other stages the bristle contains a few minute marginal filaments. The c-bristle of the 7th segment and the d-, f-, and g-bristles of the 8th segment are without filaments on instar I and bear a few minute filaments on later stages.

Mandible: Limb similar in instars and adult female; e. g., each of 3 endopod segments bears a strong ventral terminal claw, and limb is without an exopod. Adult male very different; e. g., a strong claw present only on 3rd endopod segment, and limb bears a small exopod.

Maxilla: Limb similar in instars and adult female, except endite III of instar I with four bristles compared to 6 in other stages. Male limb reduced and all bristles except those of exopod very weakly developed (difficult to count).

Fifth limb: Number of epipod bristles increases from 25 on instar I to 35 on adult female and 36 on adult male, otherwise instars and adult female similar. Limb of adult male reduced.

Sixth limb: Limb without bristles on instar I, with 1 bristle on instar II, and with many bristles on other stages.

Seventh limb: Limb bare on instars I to III, becoming longer on each succeeding stage. Instar IV female limb with 6 bristles, adult female limb with 8, and adult male limb with 4. Instar IV and adult female limbs with terminal opposing spines, which are absent on adult male.

Furca: Each lamella with 3 claws on instar I and 5 claws on other stages.

Bellonci Organ: Present and similar on all stages (lost during dissection on an adult female examined herein).

Figures

FIGURE 25. Comparison of approximate number of bristles, claws, and spines on instars and adult female appendages of Deeveya bransoni (herein) and Eusarsiella syrinx (herein).

FIGURE 26. Percent of total bristles, claws, and teeth on instars and adult female appendages of Deeveya bransoni and Eusarsiella syrinx.

FIGURE 53. Eusarsiella syrinx, new species, paratype USNM 1021464, adult male, complete specimen from right side, length with caudal process 0.98 mm.

FIGURE 54. Eusarsiella syrinx, new species, paratype USNM 1021464, adult male: a, anterior right valve, iv; b, posterior right valve, iv; c, knobbed surface bristles on rib; d, right first antenna, mv; e, left antenna, lv; f, endopod left second antenna, mv; g, exopod right second antenna, lv (nabs); h, Bellonci Organ. Scale equals 0.05 mm (a,b,e–h), 0.02 mm (c) and 0.10 mm (d).

FIGURE 55. Eusarsiella syrinx, new species, paratype USNM 1021464, adult male: a, right mandible, mv; b, left maxilla, lv; c, fifth limb; d, right sixth limb, mv; e,f, seventh limb; g, left lamella of furca (mv) and copulatory organs; h, right copulatory organ, lv; i, right Y-sclerite and ventral end of right branch of girdle; j, posterior view of girdle attached to posterior ends of Y-sclerite (dorsal end to left); k, anterior of body from right side showing lateral eye, medial eye, and second antenna (nabs). Scale equals 0.05 mm (a,d,i,j), 0.10 mm (e,g) and 0.20 mm (k).

FIGURE 56. Eusarsiella syrinx, new species, paratype USNM 1021464, adult male: a, basis, exopod, and proximal part of endopod of left mandible, mv; b, endopod left mandible, mv. Eusarsiella warneri Kornicker et al. 2002, USNM 193091, adult male: c, basis and proximal part of endopod of right mandible, lv; d, endopod left mandible, mv. Scale equals 0.5 mm (a–d).

FIGURE 57. Eusarsiella syrinx, new species, paratype USNM 1021465, adult female, complete specimen from right side, length with caudal process 1.57 mm.

FIGURE 58. Eusarsiella syrinx, new species, paratype USNM 1021465, adult female: a, oval fossae and central adductor muscle attachments (stippled) and bases of short bristles on right valve, ov; b, fragment of valve showing fossae and short bristles, ov; c, detail from Figure 57 showing upper rib (stippled) and two bristles, ov; d, detail from Figure 57 showing posterodorsal process, ov; e, caudal process of left valve, iv; f, anterior edge of right valve, iv. Scale equals 0.10 mm (a,c–e), 0.02 mm (b) and 0.20 mm (f).

FIGURE 59. Eusarsiella syrinx, new species, paratype USNM 1021465, adult female: a, left first antenna drawn on body, lv; b, anterior of body showing right lateral eye, medial eye, and parts first and second antennae; c, endopod left second antenna, mv; d, part right second antenna, mv; e, right mandible, mv; f,g, medial spines on first endopod article of left and right mandibles. Scale equals 0.10 mm (a,b,e), 0.05 mm (c,d) and 0.02 mm (f,g).

FIGURE 60. Eusarsiella syrinx, new species, paratype USNM 1021465, adult female: a, part left maxilla, mv; b, endites I–III, left maxilla, mv; c, fifth limb; d, left sixth limb, lv; e,f, left and right seventh limbs; g, right lamella and part left lamella of furca; h, left Y-sclerite and ventral end of girdle, lv. Scale equals 0.05 mm (a–d, f,h), 0.20 mm (e) and 0.10 mm (g).

FIGURE 61. Eusarsiella syrinx, new species, paratype USNM 1021466, instar IV (A-1) female: a, complete specimen from left side, length including caudal process 1.30 mm; b, detail of surface showing fossae and bristles with knobby tips; c,d, central adductor muscles of left and right valves, ov; e, caudal process right valve, iv; f, left first antenna, lv (nabs); g, endopod right second antenna, mv; h, right maxilla drawn on body, lv; i,j, part of left and right seventh limbs; k, posterior of body from right side showing part of furca, Y-sclerite, and ventral end of girdle; l, right lateral eye, medial eye, and detached Bellonci Organ; m, anterior of body and upper lip. Scale equals 0.10 mm (b–e, g–m), 0.05 mm (f).

FIGURE 62. Eusarsiella syrinx, new species, paratype USNM 1021467, instar III (A-2) (sex unknown): a, complete specimen, length including caudal process 1.02 mm; b, central adductor muscle scars left valve, ov; c, right first antenna, lv (nabs); d, endopod right second antenna, mv; e, part right mandible, mv (nabs); f, fifth limb; g, right seventh limb; h, medial eye, Bellonci Organ, and right lateral eye drawn on body. Scale equals 0.10 mm (b,g,h), 0.05 mm (c–e) and 0.02 mm (f).

FIGURE 63. Eusarsiella syrinx, new species, paratype USNM 1021468, instar II (A-3) (sex unknown): a, complete specimen from left side, length with caudal process 0.83 mm; b, central adductor muscle scars right valve, ov; c, right first antenna, lv (nabs); d, endopod right second antenna, mv; e, articles 1 and 2 of exopod right second antenna, mv (nabs); f, proximal part of left mandible, mv (nabs); g, right fifth limb, lv; h, left sixth limb, lv; i, medial eye and Bellonci Organ; j, lateral eye. Scale equals 0.10 mm (b), 0.05 mm (c,e,f,i,j) and 0.02 mm (d,g,h).

FIGURE 64. Eusarsiella syrinx, new species, paratype USNM 1021469, instar I (A-4) (sex unknown): a, complete specimen from left side, length with caudal process 0.68 mm; b, central adductor muscles as viewed through right valve; c, right first antenna drawn on body, lv (nabs); d, first and second articles of exopod of right second antenna, mv (nabs); e, endopod and part of protopod of right second antenna, mv; f,g, right mandible, mv; h, right maxilla drawn on body, mv; i, right mandible drawn on body, lv; j, left maxilla, mv (nabs); k, Bellonci Organ and medial eye;; l, right lateral eye. Scale equals 0.10 mm (b), 0.05 mm (c,e,f,h,i,k,l) and 0.02 mm (d,g,j).

FIGURE 65. Eusarsiella syrinx, new species, paratype USNM 1021469, instar I (A-4) (sex unknown): a, endite III right maxilla, lv; b, right fifth limb, lv; c, right sixth limb, mv; d, right seventh limb; e, left lamella of furca, lv; f, left lamella of furca, mv; g, posterior of body from left side showing seventh limb, Y-sclerite, and girdle. Scale equals 0.02 mm (a– d,f) and 0.05 mm (e,g).