Lowrya taiti, Parker, 1998

Parker, A. R., 1998, A new genus and two new species of Cypridinidae (Crustacea: Ostracoda: Myodocopina) from Australia, Records of the Australian Museum 50 (1), pp. 1-17 : 3-9

Lowrya taiti n.sp.

Figs 1-4

Type locality. Off Providential Head, Bate Bay, NSW, Australia (34°0TS 151°lO'E); baited trap set overnight at 46 m depth. Collected by lK. Lowry, SJ. Keable and A.R. Parker on M.V. Krista, 14-15 January 1991. Total of 70 Lowrya sp. caught in trap (62 males), in addition to 11 other species of cypridinid ostracods, 3 species of cirolanid isopods, 3 species oflysianassoid amphipods, and 1 species each of a nebaliacean, gastropod and a polychaete. Undescribed species of the cypridinid ostracods Paradoloria (926 individuals), Vargula (860) and Cypridinodes (464) constituted the dominant scavenging species.

Type material. HOLOTYPE: AM P44618, adult female . PARATYPES: AM P44619, adult male ; AM P45529, adult female ; AM P45530,'adult male ; AM P45531, 3 adult males (undissected) ; BMNH 1995 :1601-1602,2 adult males (undissected) ; NMNH, 2 adult males (undissected) .

Other material examined. AM P45532, adult male, cleaned using ultrasound, critical point dried, mounted on a scanning electron microscope (SEM) stub, and coated with gold (examined in a SEM).

Description of adult female characters.

COLOUR OFLIVINGOSTRACODS. Beige with aredareaabove the incisure visible from certain orientations.

CARAPACE. Holotype: length = l. 27 mm, height = 0.81 mm; length/height = l.57. Paratype: length = l. 36 mm, height = 0.91 mm; length/height = l.49.

Shape: rectangular oval, very slightly protruding keel; margins straight for much of length dorsally, slightly rounded ventrally ( Fig. 2E ). Keel joined by slight dorsal concave curve to curved posterior margin of valve ( Fig. 2D ); dorsal edge ofkeel at about midheight of valve; dorsal edge of incisure slightly overlapping ventral edge at inner end, line on outer surface ofvalve curving frominner dorsal edge of incisure to anterior margin of valve (ventral to incisure) is faint. Tip of rostrum rounded; with smooth adjacent margins ( Fig. 2A ).

Valve surface smooth at low magnification, but with scale-like pattern visible on anterior margins with a light microscope at 100 times magnification (as in Fig. 5C); setae on valve surface medium sized and scattered evenly; 9 muscle scars, forming a triangle with smaller scars inside triangle ( Fig. 2F ).

Infold: infold posterior to rostrum with row of 11 setae, double type, parallel to valve margin, 9 of these setae are dorsal to incisure; 1 seta posterior to carapace infold row, double type; 4 setae anterior to carapace infold row, double type. Posterodorsal edge ofincisure withoutsetae. Posterior to dorsal inner corner of incisure with 1 seta, double type. Sclerotized ridge (list) dorsal to incisure forming an angular shape within rostrum (point of angle near rostral tip), more strongly sclerotized section nearest incisure ( Fig. 2A ). Sclerotization of rostrum very strong, resulting in external lateral processes on rostrum. Anteroventral infold, near inner corner of incisure, with 6, medium length, double setae; posterior edge of carapace infold without setae. Infold parallel to anteroventral/ventral margin with 26 setae, double type, 4 of these setae in the region ventral to incisure, diminishing in length posteriorly; 1 seta anterior to anteroventrallventral row, no setae posterior to row. Left valve with 30 setae parallel to anteroventrallventral margin. In vicinity of keel, list remains constant in width, forming a shallowly curved narrow smooth ridge; keel infold simple. Ridge of keel unornamented except for minute short setae or papillae emerging from unrimmed pores, and without setae; list of left valve ending in pronounced dorsal knob, without processes. Right valve with posterior margin of keel possessing no setae, with few minute setae or papillae emerging from pores; dorsal margin of keel with pronounced projection.

Lamellarprolongation of selvage: narrow along rostrum; along lower margin of incisure selvage is broad and striated; along ventral margin selvage is narrower, terminating posteroventraUy. "Coelotrichs" (sensilla consisting of a spherical evagination of the epicuticle and a fine "hair"; Parker, submitted) ( Figs 1C ; 4D,F ) forming rows near carapace margins present: 5-6 in rostral row, 4- 5 in incisure row ( Fig. 2A ), 32-34 in ventral row, 5-6 in keel row; total of 46- 5l.

FIRST ANTENNA (Fig. 21). First article bare. Second article with medial fine spines forming rows, and spines on ventral and dorsal margins. Third article very short and slightly trapezoid, without medial spines, setae of 3rd and 4th articles ringed with short spines; third article with 1 slightly longer and stouterventral seta, distally, and 1 dorsal seta, just proximal to middle. Fourth article with 1 dorsal seta, longer than dorsal seta of 3rd article, and 1 ventral seta, sub-terminally, longer than ventral seta of 3rd article. Fifth article: s-seta with 10 proximal halophores, halophores long and bare; distally 2 non-terminal halophores, more slender and shorter (note that halophores are generally short for Cypridinidae ). Sixth article with short bare and ringed medial seta near dorsal margin. Seventh article: a-seta short (shorter than seta of 6th article), stoutand ringed with few distal spines; b-seta short, thin, ringed and bare; c-seta long and ringed, with 6 nonterminal halophores, halophores slender and bare. Eighth article: d- and e-setae (including terminal halophores) much longer than b-seta, bare and filamentous; f-seta shorter than c-seta, with 4 non-terminal halophores, halophores bare; g-seta of similar length to c-seta, with 3 non-terminal halophores, halophores bare. Bifurcate tips (2 terminal halophores) present on c-, f-, g- and s-setae.

SECOND ANTENNA. Endopodite with 3 articles ( Fig. 2K ). First article with 4 proximal setae; 2 short, 2 long. Second article elongate, with terminal long bare seta. Third article longer than 2nd article; terminal seta very long. Exopodite ( Fig. 2J ): second article bearing seta with tip reaching to about article number 8, bearing 9 ventral robust spinules, of which most proximal robust spinule is much smaller than others, and no dorsal spinules; medium-short thin spine on ventral margin of article. Articles 3-8 with basal robust setae, robust seta of 5th article longest, and with natatory setae with many setules, broad setules present on seta of 3rd article only; ventral broad setules of seta of 3rd article short and stout proximally, becoming thin setules distally. Lateralrobust seta of ninth article of similar length to that of fifth article. Ninth article with 4 setae; 2 long with many setules; 1 thinner, shorter and bare; 1 very short, thin and bare.

MANDIBLE ( Fig. 3A ). Coxal endite spinous; seta near base short, ringed and bare; 2 terminal setae, ringed and bare. Setae on ventral margin of basis: longest medial aseta short-medium long and bare, and about 2 times longer than shortest seta; shortest a-seta bare; lateral b-seta medium length and bare, positioned closer to c-setae than a-setae; longest c-seta long and bare; shortest c-seta short and bare; longest d-seta much longer than basis, with rings of long spinules; shortest d-seta much less than 0.5 times length of basis, and bare; space between c- and d-setae much larger than space between c-setae. Distal part of dorsal margin of basis with 3 setae; 1 more proximal seta, medium length and bare, and 2 subterminal setae, subequal in length, long with short spinules. Exopodite of similar length as 1st endopodial article; medial surface smooth; dorsal process withfew short spines, extending to arounded tip, and with 2 ventral setae, of which the proximal seta is long, with short spinules. Endopodite: First endopodial article with 3 ventral setae; a-seta absent, b-seta medium length with many fine spinules, c-seta long and bare, dseta long with rings of long spinules. Second endopodial article long, thin, and slightly tapered; spines (in rows) on medial surface are short and straight or slightly crescent shaped; dorsal margin with 11 setae; 1 a-, 1 b-, 1 C-, 2 dsetae; d-setae longest; d-setae long with short spinules; 5 dorsomedial shorter setae, of which there are no short, stout and unringed medial setae with long stout spinules; and 1 seta distal to d-setae. Ventral margin with few short spines, and 3 setae proximal to finger seta; no very short fine setae on ventral margin at base of finger. Finger seta about 60% length of finger. Finger long, slender with wide base, curved with rounded tip and unringed. End article with 3 claws; claws all similarly curved and of approximately equal length; longest claw longer than finger; DM (dorsomedial) claw shortest and thinnest, tapered, with an almost pointed tip, without spinules; VM (ventromedial) claw longest, proximally stout, distally tapered, with a rounded tip, bearing 1 minute spinule; VLat (ventrolateral) claw slightly shorter than VM claw, proximally stout, distally tapered, with a rounded tip, bearing 5 very long spinules. End article with 4 setae; ventromedial a-seta short, tapered, with an almost pointed tip; ventrolateral bseta very long, untapered, with a rounded tip; ventromedial c-seta medium length, broad and slightly tapered, with a rounded tip; dorsolateral d-seta long, tapered, with an almost pointed tip; b-seta longest; a-seta shortest.

FOURTH LIMB ( Fig. 3C ). Endite I with 9 setae; endite Il with 5 setae; endite III with 4 setae; trifid tips present on a few endite setae. Coxa with long dorsal seta with many setules. Basis with no lateral setae, and 2 medial setae. Exopodite bare, with 1 proximal seta, which is long with many setules; and 2 terminal setae, which are long with proximal robust setules. Endopodite: first endopodial article approximately rectangular, and bare; cutting tooth large, with 3 cusps, cusps squarish in shape, partial suture or cutting edge separating proximal part fromrest of cutting tooth present. 1 a-seta; aI-seta very long with distal setules. 2 ~-setae; 縲⵳整愠 medium length and bare, ~3- seta very long and denticulate. Second endopodial article much narrower than 1st article, with 4 a-setae: aI-seta thin with a widened base, medium length and bare, distally ringed; a2-seta thin with a widened base, long and bare, ringed throughout most of length; a3-seta thin with a widened base, long and bare, ringed throughout most of length; a4-seta thin with a widened base, long and bare, distally ringed. 3 b-setae: bI-seta medium width, medium length, ringed throughout most of length, with 6 denticles, denticles medium broad, of medium length and present distally; b2-seta medium width with a widened base, medium length, unringed, with 11 denticles, denticles narrow, short and present distally; b3-seta (most posterior) claw-like, medium length, unringed, with 2 denticles, denticles very broad, long and present centrally. 3 c-setae: cl-seta (most anterior) very thin, short and bare, ringed throughout most of length; c2-seta broad, medium length, ringed throughout most of length, with 10 denticles, denticles medium broad, long and present along most of setal length; c3-seta broad, long and spinous, ringed throughout most of length, with 10 denticles, denticles medium broad, long and present along most of setal length. 3 d-setae: dl-seta claw-like, long, unringed, with 3 denticles, denticles very broad, of medium length and present centrally; d2-seta claw-like, long, unringed, with 5 denticles, denticles broad, long and present centrally, of these denticles 2 are large, and positioned distally on the anterior side of the d2-seta; d3-seta thin with a widened base, long, distally ringed, with 10 denticles, denticles medium broad, long and present distally, of these denticles 2 are large, and positioned proximally on the anterior side of the d3-seta.

FIFTH LIMB ( Fig. 3B ). With 40 epipodial setae. Anterior distal tooth of Protopodite with rounded tip. Endite I with 6 setae; endite Il with 6 setae; endite III with 6 setae. First exopodial article: posterior row of 6 pectinate teeth (clawlike setae); tooth 1 (smallest, most posterior) with 7 denticles, tooth 2 with 7 denticles, tooth 3 with 8 denticles, tooth 4 with 9 denticles, tooth 5 with 10 denticles, tooth 6 with 12 denticles; peg large, and triangular; peg-seta medium length, stout, and with setules throughout length, peg-seta about same length as longest tooth. Anterior side of article with row of 3 setae; 1st-seta (inner) medium length, medium width, and with setules throughout length; 2nd-seta long, medium width, and with distal setules; 3rdseta long, medium width with a broadened base, with many setules and distal spinules. Additionally 1 more proximal anterior seta on 1st exopodial article, close to protopodite; proximal anterior seta medium length, thin, and with setules throughout length. Second exopodial article: with 4 a-setae, a-setae claw-like, ringed, and coarsely denticulate; 7 b-setae, b-setae medium length to long, and most ringed (posterior row of 3 b'-setae, anterior row of 4 b"-setae); posterior c-setaringed throughout most oflength, and with distal spinules; anterior d-seta unringed withmany setules. Inner lobe of third exopodial article with 3 setae; most proximal seta very short, unringed, and bare; subterminal seta long, distally ringed, and bare; terminal seta medium length, distally ringed, and bare. Outer lobe of 3rd exopodial article hirsute with 2 medium broad setae; outer seta medium length, unringed, and with proximal setules. Fourth and fifth exopodial articles fused and hirsute. Fourth article with 1 medium broad seta. Fifth article with 2 medium broad setae, subequal in length, unringed, with many spinules. Terminal process on inner 5th article medium sized with long spines and a group of spines forming a triangular sub-process.

SIXTH LIMB ( Fig. 3D ). With 5 setae in place of epipodite; these setae are bare and ringed. Endites with medial setae. Endite setae: 1= 3; 1 long, distally ringed, with short distal setules, and without robust setules; 2 very short, medium width, ringed, with short setules, without robust setules. Il = 5 setae; 2 long, distally ringed, with long proximal setules and short distal robust setules; 3 medium short, medium width with broad base, ringed, with long setules, without spinules. III = 3 setae; 2 long, distally ringed, with long proximal setules and short distal robust setules; 1 medium short, thin with broad base, ringed, with long proximal setules and without robust setules. IV = 2 setae; 1 very long, distally ringed, with long central setules and short distal robust setae; 1 medium long, thin with broad base, ringed, with long central setules and without robust setae. Endites separated from each other and rest of limb by sutures or grooves. Terminal article approximately square shaped, basally separated by suture or groove from rest of limb; medial surface hirsute; lateral surface with rows of stout long setae along ventral margin. 5 anterior ventral terminal setae, with broad bases abruptly constricting to a narrow distal width, distally ringed, with long proximal setules and long distal spinules; setae of terminal article reducing evenly in length from most anterior seta to most posterior, with bases on margin of article; gap posterior to anterior ventral terminal setae long, including a rounded corner and a small anteriorrecess, gap = about 40% ventral length of terminal article, followed by 3 posterior setae, mostly unringed, some with bases on edge of article, some with bases set back from edge, the longest is the most posterior; the most anterior is medium length, with a broad base abruptly constricting to a narrow distal width, with long proximal setules and long distal spinules.

SEVENTH LIMB ( Fig. 3E ). Total of 9 setae. Comb side with 1 nonterminal seta, and 3 terminal setae; minimum number of bells on setae = 4, maximum number of bells on setae = 6. Peg side with 2 nonterminal setae, and 3 terminal setae; minimum number of bells on setae = 4, maximum number of bells on setae = 6. Comb of 3 long teeth on each side, coarsely denticulate, with rounded tips, central tooth slightly longer than others; 2 short teeth on each side, medium length, with square tips, and deep grooves. Peg medium length, slightly curved, narrow; tip of peg similar width to centre of peg, with many points; base of peg recessed from outer limb edge.

FuRCA ( Fig. 2B ). Left lamella with 7 claws, right lamella with 7 claws; claws 2 and 4 fused to lamella; claw 3 shorter and thinner than claw 4; claw 1 long and medium wide; claw 4 exceptionally broad; claw 5 short and thin; anterior claws short and thin; claws generally increasing in size posteriorly (with exception). Claws generally evenly curved, four most posterior claws with spinules; distal medial robust setules of most posterior claw absent. Lamellae elongate, tapered and bare.

ANTERIOR OF BODY ( Fig. 2H ). Bellonci organ: shape (non-extended) is square; length (non-extended) = 0.03 mm; width similar to length; slightly pigmented.

Eyes: medial eye ( Fig. 2H ) medium sized; length = 0.04 mm; pigmented. Lateral eye ( Fig. 2G ): length = 0.18 mm; large (about 20 times size of medial eye); broadest dorsally; with at least 16 ommatidia, largest ommatidia located dorsally; ommatidia light amber in transmitted light, pigment between ommatidia maroon in transmitted light.

Upper lip ( Fig. 2H ): single undivided anterior part directed anteroventrally, ventral field of anterior part pearshaped, with about 18 valves; valves large, and arranged in about 3-5 anterior-posterior rows on a single plane; anterior part bare. Pair oflateral tusks short, medium width with parallel margins, each with 1 valve, valves medium sized, positioned terminally; tusks not hirsute; spurs on tusks absent; tusks terminating at a rounded posterior corner. Upper lip pigmented.

Frontal knob ( Fig. 2H ): very elongate, rounded, width less than length; without projections ventral to frontal knob.

POSTERIOR OF BODY. Dorsal folds absent. Y-sclerite with ventral branch shorter than 50% length of dorsal branch.

Description of adult male characters

Most characters common to both sexes have been omitted from the following description.

CARAPACE ( Fig. 4A,B ). Length = 1.12-1.20 mm (number of specimens examined = 9), height = 0.80 mm; lengthlheight = 1.5. Coelotrichs: 4 in rostral row, 3 in incisure row, 27 in ventral row, 4 in keel row; total of 38.

FIRST ANTENNA ( Fig. 4D ). Fifth article: s-seta with 8 bare proximal halophores (most proximal 6 halophores longest and separated by a small gap from more central 2 halophores), and 2 shorter, bare, distal non-terminal halophores. Seventh article: b-seta with basal setule with bulbous base, large proximal "sucker" (transparent), without non-terminal halophores, additionally 2 setules present, each bearing 7 small "suckers", small process j~st proximal to most proximal "sucker" present; c-seta wIth bulbous base with large basal setule with sub-terminal process, and additional cup-shaped basal process from which a large "sucker" (diameter greater than width of each of the distal five articles; transparent) arises, 6 short and slender non-terminal halophores, additionally 2 proximal setules, each bearing 6-7 small "suckers", small process just proximal to most proximal "sucker" present. Eighth article: f-seta with 5 non-terminal halophores, with short spinules; g-seta with 11 non-terminal bare halophores.

COPULATORY "LIMB" ( Fig. 4E,F ). First article: Y-sclerite prominent; strut present so that the sclerite forms an irregular rectangular loop; loop broader distally; finger sclerite medium wide, terminating at distal tip of finger branch. Inner lobe elongate with rounded tip. Finger branch and setal branch separated by a deep terminal cleft; tip of finger branch with many minute scales. Terminal and cleft region of setal branch bears minute scales; external surface of setal branch with 6 setae, ringed and bare. Outer lobe with thumb sclerite terminating at dorsal hood edge; thumb small and bare, located proximally on thumb sclerite, near hood; thumb with 3 ringed, bare setae, located proximal to tip of thumb sclerite. Hood: dorsoventral margin medium length, distally triangular, with an anterior step-like constriction, becoming a fingerlike lobe; length of anterior peak small; tip of hood complete, with few minute scales or spines. Hood extends less than half way over inner lobe. Central lobe: width about equal to length; length = about 50% of that of inner lobe. The central lobe bears 3 terminal setae, which are ringed with spinules.

ANTERIOR OF BODY (Fig. 5A). Lateral eye: very large, length = 0.20 mm; broadest dorsally; at least 16 ommatidia (7 large, of approximately equal size; about 9 small, of approximately equal size), largest ommatidia located dorsally.

Etymology. This species is named in honour of Noel N. Tait, invertebrate zoologist, who provided the author with much invaluable advice on zoological subjects.

Figures

Fig. 1. Definitions of hair-like structures used in the following species descriptions.

Fig. 2. Lowrya taiti, adult female (AM P446l8). A, anterior of right carapace valve, medial view (area of sclerotization shaded). B, left furcal lamella, lateral view. C, appearance of coelotrichs (in anteroventral section of left carapace valve) at 200 times magnification, lateral view (setae not visible). D, posterior (keel) of right carapace valve, medial view. E, right carapace valve, medial view. F, central adductor muscle scars of right carapace valve, medial view. G, left lateral (compound) eye, lateral view (dorsal above). H, anterior of body, limbs removed, showing medial eye (m.e.), Bellonci organ (b.o.), frontal knob (f.k.), and upper lip. I, right 1st antenna, medial view. J, exopodial articles 2-9 of left 2nd antenna, including seta of 3rd article, medial view. K, endopodite of right 2nd antenna, medial view.

Fig. 3. Lowrya taiti adult female (AM P44618). A, right mandible, medial view. B, terminal part of 5th limb, anterior view, showing endites (I, 11 and Ill), and exopodial articles (1-5). B(i), terminal process of 5th exopodial article. B(ii), terminal part of 2nd bOO-seta. B(iii), longest a-seta. B(iv), longest "tooth". B(v), peg. C, right 4th limb, medial view. D, right 6th limb, lateral view, showing endites (I-IV). E, terminal part of 7th limb, showing peg.

Fig. 4. Lowrya taiti adult male (AM P44619). A-left carapace valve, medial view, showing rows of coelotrichs. B-anterior of right carapace valve, medial view. C-smallest "tooth" and peg of left 5th limb, anterior view. D-terminal part of right first antenna, lateral view, shaft of b-seta missing. D(i), 3rd most proximal halophore of the f-seta. E-left copulatory "limb", ventral view, showing internal sclerites. F-terminal part of left copulatory "limb", ventral view. G-VM claw of right mandible, lateral view. H-VLat claw of right mandible, lateral view. I-terminal part of seta of 2nd exopodial article of the right 2nd antenna, lateral view, showing small medial spine.