Indocaris imbricata, Reddy & Totakura & Shaik, 2016
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publication ID |
https://doi.org/ 10.1080/00222933.2015.1130870 |
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publication LSID |
lsid:zoobank.org:pub:814E71CA-6313-49F3-B989-3D903DEEFA4A |
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persistent identifier |
https://treatment.plazi.org/id/03DDE441-FFF7-FFEB-FE42-FAF59A9BFB04 |
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treatment provided by |
Felipe |
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scientific name |
Indocaris imbricata |
| status |
gen. nov., sp. nov. |
Indocaris imbricata gen. nov., sp. nov.
( Figures 1–7 View Figure 1 View Figure 2 View Figure 3 View Figure 4 View Figure 5 View Figure 6 View Figure 7 )
Type locality
Farm bore (water temperature 26°C, pH 7.0) at Chintalapudi village , ~ 5 km from Nidubrolu town (16°02′23.8″N, 80°32′35.4″E; elevation 36.5 m) in Guntur District, Andhra Pradesh, southeastern India ( Figure 1 View Figure 1 ) GoogleMaps .
Type material examined
Holotype male (MNHN-IU-2013–11941) and allotype female (MNHN-IU-2013–11942), dissected on four slides each; five paratypes: one male (MNHN-IU-2013–11943) dissected
on two slides and one female (MNHN-IU-2013–11944) dissected on four slides, two males (MNHN-IU-2013–11945-11946) and one female (MNHN-IU-2013–11947) wholemounted on one slide each; 5 February 2010, Coll. V. R. Totakura.
Other material examined
Farm bore (water temperature 26°C, pH 7.0) at Kunchanapalli village (16°23′42.1″N, 80° 32′28.2″E; elevation 26 m) near Vijayawada city, in Guntur District, Andhra Pradesh, southeastern India; two males and 20 females in alcohol in one vial (MNHN-IU-2013– 11948), 5 February 2012, Coll GoogleMaps . V. R. Totakura.
Etymology
The new species is named imbricata (Latin adjective), meaning overlapping, alluding to the characteristic arrangement of the modified spinules at the base of the male leg 4 endopod.
Description of adult male
Total body length, measured from tip of rostrum to posterior margin of caudal rami, 250–330 μm (285 μm in holotype). Preserved specimens colourless. Nauplius eye absent. Habitus ( Figure 2A View Figure 2 ) cylindrical and slender, without any demarcation between prosome and urosome; prosome/urosome ratio about 0.8 in lateral view; greatest width in dorsal view at cephalothorax. Body length/width ratio about 5.8. Free pedigerous somites without any lateral or dorsal expansions, all connected by well-developed arthrodial membranes. Hyaline fringes of all somites smooth, very narrow and hard to distinguish from arthrodial membranes. Integument weakly sclerotised, smooth, ornamented only with sensilla and pores (no spinules), with dorsal cuticular double-window on cephalothorax, and elliptical dorsal, simple cuticular window each on genital somite and next three somites. Pleural areas of cephalothorax and free pedigerous somites moderately developed; cephalic appendages and coxae of swimming legs clearly exposed in lateral view. Rostrum (not drawn) small, linguiform, membranous, as long as wide, not demarcated at base, ornamented with two dorsal sensilla. Cephalothorax ( Figure 2A View Figure 2 ) about as wide as genital somite and somewhat dilated distally, 1.3 times as long as wide in lateral view, representing 21.5% of total body length. Surface of cephalic shield ornamented with eight pairs of large sensilla (no cuticular pores or any other ornamentation); posterior half of cephalothorax widest in dorsal view; free pedigerous somites 2–4 gradually widening and with narrow, smooth hyaline fringes. Second pedigerous somite with one pair of mid-dorsal and one pair of lateral sensilla. Third somite as long as second one but slightly wider and ornamented with three pairs of distal sensilla. Fourth pedigerous somite widest of all prosomites in dorsal view, slightly shorter than third prosomite, with three pairs of sensilla. First urosomite about as wide as, but longer than, fourth pediger, and also with only three pairs of sensilla. Genital somite widest of all urosomites and with two pairs of posterior sensilla. Third urosomite narrower and shorter than first urosomite and with three pairs of large posterior sensilla; fourth urosomite longer than third one, with three pairs of sensilla; preanal somite as long as fourth urosomite and without any surface ornamentation. Anal somite about 0.7 times as long as preanal somite and ornamented with one pair of large dorsal sensilla at base of anal operculum and one proximo-lateral cuticular pore, but without any spinules. A single large, longitudinally placed spermatophore ( Figure 2A, B View Figure 2 ) discernible through cuticle of genital somite and next two somites; spermatophore about 2.9 times as long as wide, kidney-shaped, with curved, narrow neck. Anal operculum ( Figure 2A View Figure 2 ) well developed, with smooth and almost straight distal margin, reaching posterior end of anal somite. Anal sinus wide open and ornamented with fine spinules.
Caudal rami ( Figure 2A, B View Figure 2 ) subcylindrical, parallel to body somites, inner margin convex, outer margin nearly straight; about 2.7 times as long as greatest width in ventral view; three times as long in lateral view and about 0.6 times as long as anal somite, with space between them about 1.7 times as long as maximum width of ramus; with full complement of seven setae (three lateral, one dorsal, two apical and one subapical); spinules occurring at inner distal corner ventrally and one pore proximo-laterally. Dorsal seta (VII) slender, plumose, inserted close to inner margin at distal third and opposite to lateral group of setae, but 1.2 times as long as caudal ramus, biarticulate basally. Inner apical seta (VI) smooth, inserted close to ventral margin, about 0.7 times as long as ramus. Middle apical seta (V) somewhat swollen at base, without breaking plane, unipinnate, about five times as long as ramus, pointing distally. Outer subapical seta (IV) without breaking plane, 1.2 times as long as ramus, inserted close to dorsal surface caudally.
Antennule ( Figure 3A View Figure 3 ) slightly longer than cephalothorax, slender, eight-segmented, prehensile, coiled type, digeniculate, geniculation between third and fourth, and sixth and seventh segments. First segment short, ornamented with one row of fine spinules; segments 3–5 only slightly dilated, aesthetasc on segment 5 large, balloon-like, with rounded tip, overreaching ultimate segment, and fused basally to simple seta; apical aesthetasc on eighth segment shorter and slenderer, about as long as segment, slightly constricted at midlength, fused basally with two setae (acrotheck). Setal formula: 0.6.4.1.0.5+aes.0.9+aes. All setae smooth except proximalmost seta on second segment unipinnate. Length ratios of segments from proximal to distal end and along caudal margin 1.0:3.5:1.4:0.7:1.5:1.4:1.4:1.9.
Antenna ( Figure 3B View Figure 3 ) composed of coxa, allobasis, one-segmented endopod and onesegmented exopod. Coxa very short, unarmed and ornamented with one row of short spinules. Allobasis about five times as long as maximum width, unarmed but ornamented with one ventral row of spinules near inner margin. Exopod small, cylindrical, about 2.6 times as long as wide, unornamented and armed with unipinnate apical seta, which is 1.8 times as long as segment. Endopod 0.5 times as long as allobasis and about 2.3 times as long as wide, with surface frill distally, ornamented with three large ventral spinules on inner margin, armed with two short unequal spines laterally and with five strong apical elements (two spines, two geniculate setae and one unipinnate transformed seta).
Labrum ( Figure 2A View Figure 2 ) triangular in lateral view.
Mandible ( Figure 3C, D View Figure 3 ) coxa with narrow cutting edge, elongate, armed with two complex teeth ventrally, one unipinnate seta dorsally, and several small teeth. Palp onesegmented, cylindrical, somewhat dilated distally, about 3.1 times as long as wide, unornamented and armed apically with two smooth, subequal apical setae.
Maxillule ( Figure 3E View Figure 3 ) praecoxal arthrite rectangular, about 2.3 times as long as wide in lateral view, armed with strong lateral seta and three claw-like apical elements. Coxal endite armed with one smooth apical seta. Basis slightly longer than coxal endite, armed with three smooth apical setae. Exopod and endopod absent.
Maxilla ( Figure 3F View Figure 3 ) composed of syncoxa, basis and one-segmented endopod. Syncoxa with two endites, basal one shorter than distal endite, armed with two smooth apical setae, distal endite armed with three smooth apical setae. Allobasis prolonged into strong unipinnate claw and without seta at base. Endopod represented by small segment, 1.2 times as long as wide, armed with two smooth apical setae.
Maxilliped ( Figure 3G View Figure 3 ) syncoxa short and relatively strong, unarmed and unornamented; basis slender, 4.7 times as long as wide, unornamented and unarmed; endopod smallest with unipinnate claw, 0.7 times as long as basis.
Leg 1 ( Figure 4A View Figure 4 ) coxa ornamented with one arched row of fine spinules near distal margin. Basis shorter than coxa, trapezoidal; ornamented with one row of spinules at base of exopod and another but shorter spinular row at base of endopod; armed with small, smooth seta on outer margin and one strong, small, hook-like spine at inner distal angle. Exopod three-segmented, bent inwards, with each segment bearing one row of spinules along outer margin; armed with one small, outer bipinnate spine on first segment; first segment 0.7 times as long as next two segments combined; second segment unarmed and four elements on third segment (one outer spine, one apical seta and two apical geniculate setae). Endopod two-segmented, longer than exopod; first segment about 1.2 times as long as proximal two exopodal segments combined, 4.7 times as long as wide, unarmed, ornamented with one row of elongate, widely spaced spinules along outer and inner margins; second segment thin, ornamented with one row of spinules on outer margin, armed with one spine subapically and one long, geniculate seta apically; endopodal geniculate seta about as long as entire endopod, twice as long as outer spine on endopod, 0.9 times as long as inner geniculate seta on exopod. All exopodal and endopodal armature elements unipinnate along outer margin except bipinnate spine on first exopodal segment.
Leg 2 ( Figure 4B View Figure 4 ) coxa ornamented with one arched row of small spinules medially. Basis slightly smaller than coxa, unarmed, ornamented with one arched row of spinules near outer margin and one proximal pore. Exopod three-segmented, each segment ornamented with spinules along outer margin, as illustrated; hyaline frill at inner distal corner of first and third exopodal segments, but second segment with one row of spinules at inner distal corner. First segment 0.9 times as long as next two segments combined, armed with moderately large outer spine; second segment unarmed; third segment armed with three long setae: two apical and one subapical; innermost apical seta 1.9 times as long as exopod. Endopod one-segmented, subcylindrical (distal part only slightly dilated), 3.5 times as long as wide, 0.3 times as long as first exopodal segment; apical margin armed with smooth seta, which is 0.9 times as long as segment, and ornamented with three spinules.
Leg 3 ( Figure 4C View Figure 4 ) coxa trapezoidal, smaller than basis, ornamented with one arched row of spinules at distal outer angle. Basis robust and produced at inner distal corner into knob-like protuberance; ornamented with anteriorly directed row of spinules along inner margin, one oblique row of spinules at outer distal angle and one pore on anterior surface; and armed with basally articulate, long, slender seta on outer margin. Endopod represented by a small seta, inserted on inner margin at two thirds of basis length. Exopod one-segmented; ancestral proximal segment moderately stout, gradually tapering, outer margin straight, inner margin only slightly curved, 2.9 times as long as wide in ventral view; ornamented with one row of fine spinules on outer distal margin and one transverse row of fine spinules at base of thumb. Apophysis bilobed (one of the lobes probably representing a remnant of fused apical seta); thumb stout, spiniform, with distinct base, longer than apophysis.
Leg 4 ( Figures 4D, E View Figure 4 , 5A View Figure 5 ) coxa rhomboidal, ornamented with one row of small spinules near distal margin. Basis shorter than coxa and subquadratic, ornamented with one arched row of small spinules on posterior surface and one oblique row of spinules on outer margin; armed with long seta on outer margin; six large, imbricate, petaloid spinules lying at insertion of endopod and increasing in size from internal to external. Exopod three-segmented, slightly bent inwards, with each segment bearing spinules along outer margin, and hyaline frill at inner distal corner of first and third exopodal segments but second segment with one row of spinules at inner distal corner; first segment 0.8 times as long as next two segments combined, armed with moderately strong bipinnate outer spine subdistally, 0.6 times as long as segment; second segment unarmed; third segment slightly longer than preceding segment, armed with two apical, bipinnate setae; inner apical seta 2.3 times as long as smaller outer seta, 3.3 times as long as third exopodal segment, about 1.2 times as long as entire exopod. Endopod one-segmented, proximal half dilated, distal part tapering off into an incurved spiniform process, exceeding the posterior border of first exopodal segment and ornamented with three or four tiny spinules at midlength of outer margin.
Leg 5 ( Figures 2B View Figure 2 , 5B View Figure 5 ) without intercoxal sclerite; elongate trapezoidal plate, ornamented with longitudinal row of eight small, almost equal spinules along inner margin and one small cuticular pore proximally; inner spiniform process acuminate, reaching almost proximal third of next somite, distal margin oblique, armed with three setae. Outermost seta long, articulate at base, and arising from small lobe; one small seta (probably ancestral exopodal seta) on lobe; another long seta on inner lobe.
Leg 6 ( Figures 2B View Figure 2 , 5D, E View Figure 5 ) smooth, unarmed, forming simple operculum covering gonopore, fused with somite; spiniform, triangular plate-like structure.
Description of adult female
Body length, excluding caudal setae, 260–350 μm (260 μm in allotype). Habitus ( Figure 6A, B View Figure 6 ): ornamentation of prosomites, colour, etc., similar to male, except genital and first abdominal somites fused into double-somite, and habitus slightly stronger.
Genital complex ( Figure 6C View Figure 6 ) occupying anterior ventral half and distinctly broader than high; single genital aperture and median copulatory pore covered by fused, vestigial sixth legs; seminal receptacles small, hard to distinguish from internal tissue and gut content; copulatory duct very short and weakly sclerotised. Preanal and anal somites almost as in male.
Caudal rami ( Figure 6A–C View Figure 6 ) similar to those of male in relative proportions and arrangement and size of setae.
Antennule ( Figure 3H View Figure 3 ) seven-segmented, ornamented on first segment with few minute spinules on ventral surface, aesthetasc on fourth segment large, somewhat constricted at midlength, reaching end of ultimate segment, aesthetasc on seventh segment much slenderer and shorter than that on segment 4 and fused basally to two apical setae; setal formula: 0.5.4.4+aes.1.0.9+aes. All setae smooth except unipinnate proximalmost one on second segment. Length ratios of segments, from proximal to distal end and along caudal margin 1.0:2.8:1.4:1.3:0.9:0.8:1.8.
Antenna, labrum, mandible, maxillule, maxilla, and maxilliped similar to male.
Leg 1 ( Figure 7A View Figure 7 ) coxa rhomboidal, ornamented with one arched row of spinules near distal margin; basis trapezoidal, armed with one slender outer seta, ornamented with one row of spinules at base of exopod and one row near inner margin; armature and ornamentation of exo- and endopod similar to those of male.
Leg 2 ( Figure 7B View Figure 7 ) exopod similar to that of male. Endopod cylindrical, 3.8 times as long as wide, 0.4 times as long as first exopodal segment, other details same as in male but apical seta longer.
Leg 3 ( Figure 7C View Figure 7 ) coxa with arched row of spinules near distal margin. Basis ornamented with one row of spinules on outer margin and armed with long and smooth outer seta. Exopod two-segmented, ornamented with large spinules along outer margin, both segments with hyaline frill each at inner distal corner; first segment armed with outer spine and long spinules on outer distal margin; second segment with subapical outer spine and apical strong seta, and three spinules on outer margin; seta 3.4 times as long as spine; all elements bipinnate. Endopod greatly reduced to small, simple stub-like structure with blunt end.
Leg 4 ( Figure 7D View Figure 7 ) exopod similar to that of male; endopod slender, straight, 1.7 times as long as first exopodal segment, tapering into acuminate point, lateral margins of distal half fringed with spinules.
Leg 5 ( Figures 5C View Figure 5 , 6C View Figure 6 ) as in male, but large in size with longer distal inner spinous process and ornamented with one small pore; inner margin smooth.
Leg 6 ( Figure 6C View Figure 6 ) unarmed, unornamented plate-like operculum covering gonopores and fused with its somite.
Variation
The number of the petaloid spinules on the male leg 4 basis is either five or six ( Figure 5A View Figure 5 ).
Distribution
This species is known only from two farm bores, about 50 km apart, in Guntur District, Andhra Pradesh state.
Ecology
At Kunchanapalli, Indocaris imbricata sp. nov. was found co-existing with Atopobathynella sp. , Habrobathynella sp. , Serbanibathynella sp. , Rybocyclops sp. , Nitocrella sp. , Dussartstenocaris sp. , unidentified harpacticoids, mites, nematodes, oligochaetes and insect larvae, and at Chintalapudi (05 February 2010) with Serbanibathynella sp. and Rybocyclops sp.
| V |
Royal British Columbia Museum - Herbarium |
| R |
Departamento de Geologia, Universidad de Chile |
No known copyright restrictions apply. See Agosti, D., Egloff, W., 2009. Taxonomic information exchange and copyright: the Plazi approach. BMC Research Notes 2009, 2:53 for further explanation.