Indocaris inopinata, Reddy & Totakura & Shaik, 2016
|
publication ID |
https://doi.org/ 10.1080/00222933.2015.1130870 |
|
publication LSID |
lsid:zoobank.org:pub:814E71CA-6313-49F3-B989-3D903DEEFA4A |
|
persistent identifier |
https://treatment.plazi.org/id/03DDE441-FFE2-FFE0-FE43-FB4C9F05FE71 |
|
treatment provided by |
Felipe |
|
scientific name |
Indocaris inopinata |
| status |
gen. nov., sp. nov. |
Indocaris inopinata gen. nov., sp. nov.
( Figures 1 View Figure 1 , 8–13 View Figure 8 View Figure 9 View Figure 10 View Figure 11 View Figure 12 View Figure 13 )
Type locality
Bore-well (water temperature 27°C; pH 7.0) at Block II on Acharya Nagarjuna University campus, Nagarjunanagar, ~ 12 km ENE of Guntur city (16°22′41.0″N, 80°31′39.4″E; elevation 19.8 m) in Guntur District , Andhra Pradesh, South India ( Figure 1 View Figure 1 ) GoogleMaps . The well, which is approximately 55 m deep, accesses a groundwater aquifer developed in garnet-sillimanite gneiss (‘khondalite’) bedrock, belonging to the Eastern Ghats group, which is approximately 3000 million years old . There is ample evidence that the Acharya Nagarjuna University campus area sustained marine transgressions during the Cenozoic (see Holsinger et al. 2006).
Type material examined
Holotype male (MNHN-IU-2013–11949) and allotype female (MNHN-IU-2013–11950) dissected on two slides each; five paratypes: one male (MNHN-IU-2013–11951) and one
female (MNHN-IU-2013–11952), dissected on two slides each, and three females (MNHN- IU-2013–11953-11955), whole-mounted each on one slide; one male dissected on two slides in junior author’ s personal collections; 19 November 2003, Coll . Y . Ranga Reddy.
Etymology
The specific epithet is derived from the Latin adjective ‘ inopinatus ’, meaning ‘unexpected’ and alluding to the fortuitous discovery of this interesting taxon. The name agrees in gender with the (feminine) generic name.
Description of adult male
Total body length, measured from tip of rostrum to posterior margin of caudal rami, 201–345 μm (340 μm in holotype). Preserved specimens colourless. Nauplius eye absent. Habitus ( Figure 8A View Figure 8 ) cylindrical and slender, without any demarcation between prosome and urosome; prosome/urosome ratio about 0.7 in dorsal view; pedigers 2–3 slenderer than urosome in dorsal view, greatest width in dorsal view at first urosomite. Body length/width ratio about 8.8. 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 with sensilla, spinules and pores (no cuticular pits), with dorsal cuticular double window on cephalothorax, and somewhat elliptical, dorsal cuticular window each on genital somite and next three somites. Pleural areas of cephalothorax and free pedigerous somites well developed. Rostrum ( Figures 8A View Figure 8 , 9A View Figure 9 ) small, linguiform, membranous, 1.2 times as long as wide, demarcated at base, ornamented with two long dorsal sensilla. Cephalothorax ( Figure 8A View Figure 8 ) about 0.9 times as wide as genital somite, about 2.4 times as long as wide in dorsal view and representing 11.5% of total body length. Surface of cephalic shield ornamented with eight pairs of large sensilla; free pedigerous somites 2–4 gradually widening. 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 as wide as prosomites in dorsal view, slightly longer than third prosomite, with two pairs of sensilla. Urosomites gradually narrowing distad. First urosomite widest of all urosomites, longer than fourth prosomite and with only two pairs of sensilla. Genital somite shorter than first urosomite, ornamented with two pairs of posterior sensilla. Third and fourth urosomites about as long as genital somite, with two pairs of large posterior sensilla; preanal somite 0.8 times as long as fourth urosomite and without any surface ornamentation. Anal somite 1.2 times as long as wide, ornamented with one pair of large dorsal sensilla at base of anal operculum, one proximo-lateral cuticular pore and two groups of small spinules ventro-laterally. A single large, longitudinally placed spermatophore ( Figure 8B View Figure 8 ) discernible through cuticle of fifth and genital somite; spermatophore about 2.7 times as long as wide, kidneyshaped, with curved, narrow neck. Anal operculum well developed, unornamented, with slightly serrulate and almost straight distal margin, not reaching posterior end of anal somite, representing 57.6% of somite’ s width. Anal sinus wide open and ornamented with fine spinules ventrally.
Caudal rami ( Figure 8A, B View Figure 8 ) subcylindrical, straight, inner margin convex, outer margin nearly straight in lateral view; 2.9 times as long as wide in lateral view, about 3.3 times as long as greatest width in dorsal view, and about 0.6 times as long as anal somite, with space between them about 2.9 times as long as that of one maximum width of caudal ramus; with full complement of setae (three lateral, one dorsal, one subapical, two apical); spinules occurring at inner distal corner and one pore disto-laterally. Dorsal seta (VII) inserted close to inner margin at distal third and opposite to lateral group of setae, slightly longer than caudal ramus, biarticulate basally. Inner apical seta (VI) smooth, inserted close to ventral margin, about 1.2 times as long as ramus. Middle apical seta (V) somewhat swollen at base, without breaking plane, bipinnate and about 5.2 times as long as ramus. Outer subapical seta (IV) without breaking plane and unipinnate and inserted close to dorsal surface.
Antennule ( Figure 9I View Figure 9 ) somewhat longer than cephalothorax, slender, eight-segmented, slightly prehensile, coiled type, digeniculate, geniculation between third and fourth, and sixth and seventh segments. First segment short, ornamented with one row of spinules; segments 3–5 barely dilated; aesthetasc on segment 5 elongate, constricted at midlength, with narrow tip, overreaching ultimate segment and fused basally to simple seta; apical aesthetasc on eighth segment staff- like, shorter and slenderer than segment, fused basally with two setae (acrotheck). Setal formula: 0.6.4.1.3+aes.1.0.9+aes. All setae smooth except proximalmost seta on second segment unipinnate. Length ratios of segments, from proximal to distal end and along caudal margin, 1.0:3.9:1.5:0.5:2.2:1.5:1.4: 2.1.
Antenna ( Figure 9C View Figure 9 ) composed of coxa, allobasis, one-segmented exopod and onesegmented endopod. Coxa short, unornamented and unarmed. Allobasis 3.8 times as long as maximum width, unarmed but ornamented with two arched rows of spinules on anterior margin. Exopod small, cylindrical, about thrice as long as wide, unornamented and tipped with bipinnate seta, which is 2.5 times as long as segment. Endopod about 0.6 times as long as allobasis and about 2.8 times as long as wide, with surface frill distally, ornamented with two rows of spinules on inner margin, armed laterally with two short unequal, bipinnate spines and apically with five strong elements (two spines, two geniculate setae and one transformed unipinnate seta).
Labrum ( Figure 9D View Figure 9 ) subtriangular, with fine denticles on distal margin in lateral view.
Mandible ( Figure 9E View Figure 9 ) narrow cutting edge on elongate coxa bearing two complex teeth ventrally, one unipinnate seta dorsally, and several small teeth. Palp one-segmented, cylindrical, about 3.6 times as long as wide, unornamented and armed with 2 smooth, slightly unequal, apical setae.
Maxillule ( Figure 9F View Figure 9 ) praecoxal arthrite rectangular, about 2.2 times as long as wide in lateral view, armed with strong lateral seta and three 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 9G View Figure 9 ) composed of syncoxa, basis and one-segmented endopod. Syncoxa with two endites, proximal one short, armed with two smooth setae apically, distal endite armed with three smooth setae apically. Allobasis prolonged into strong, distally unipinnate claw, and without seta at base. Endopod represented by small segment, bearing two smooth apical setae.
Maxilliped ( Figure 9H View Figure 9 ) syncoxa short, unarmed and unornamented; basis slender, 5.3 times as long as wide, unornamented and unarmed; endopod small with unipinnate claw, 0.8 times as long as basis.
Leg 1 ( Figure 10A View Figure 10 ) coxa trapezoidal, ornamented with one row of spinules near mid-distal margin. Basis shorter than coxa, trapezoidal; ornamented with one row of spinules on outer margin, one row near base of exopod and another row at base of endopod, armed with one small, smooth seta on outer margin and one small outcurved, blunt, knob-like, small spine at inner distal angle. Exopod three-segmented, sharply bent inwards, each segment bearing a row of spinules along outer margin; armed with one small, outer bipinnate spine on first segment; first segment about 0.8 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 and longer than exopod; first segment about 1.4 times as long as proximal two exopodal segments combined, five times as long as wide, unarmed, ornamented with elongate spinules along outer and inner margins; second segment thin, ornamented with elongate spinules along outer and inner margins, armed with one spine subapically and one long, geniculate seta apically; geniculate seta about as long as entire endopod, 2.6 times as outer spine on endopod, about 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 10B View Figure 10 ) coxa ornamented with one row of spinules medially near distal margin. Basis slightly smaller than coxa, unarmed, ornamented with one row of small spinules on outer margin and one proximal pore. Exopod three-segmented; first segment with three short rows of spinules on outer margin; second and third segments with one distal row of spinules each on outer margin; 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 0.7 times as long as next two segments combined, armed with outer spine; second segment unarmed; third segment armed with three long elements (one subapical, two apical setae); innermost one 1.4 times as long as exopod. Endopod one-segmented, subcylindrical, distal part only slightly swollen, thrice as long as wide, 0.4 times as long as first exopodal segment, apical margin with three small spinules and one smooth seta, which is 0.8 times as long as segment and pointing inwards.
Leg 3 ( Figure 10C View Figure 10 ) coxa trapezoidal, much smaller than basis, ornamentation not discernible. Basis robust and produced at inner distal corner into simple subtriangular plate-like structure; ornamented with one row of spinules on outer margin, one anteriorly directed row of spinules near inner margin and one pore on anterior surface, armed with moderately long, basally articulate, slender seta on outer margin. Endopod represented by small seta, inserted on inner margin at two thirds of basis length. Exopod having two partly fused segments; ancestral proximal segment moderately stout, 2.6 times as long as wide in ventral view, inner margin only slightly curved, with small bulbous hyaline structure; ornamented with one row of spinules on outer distal angle and one transverse row of fine spinules at base of thumb. Apophysis with vague septum at base and pyriform in outline and without any seta. Thumb moderately strong, somewhat spiniform with acuminate tip, and longer than apophysis.
Leg 4 ( Figure 10D, E View Figure 10 ) coxa trapezoidal, ornamented with one row of spinules at outer distal angle. Basis shorter than coxa, rectangular and armed with small seta on outer margin; five large, imbricate, petaloid spinules lying at the insertion of endopod and increasing in size from internal to external. Exopod three-segmented and ornamented with rows of spinules along outer margins of all segments, as illustrated; hyaline frill on inner distal corner of first and third exopodal segments but second segment with one row of spinules at inner distal corner; first segment about half as long as next two segments combined, armed with moderately strong bipinnate outer spine subdistally; second segment unarmed; third segment slightly longer than second exopodal segment, armed with two apical, bipinnate setae; inner apical seta 4.4 times as long as outer seta, about five times as long as third exopodal segment, nearly twice as long as entire exopod. Endopod one-segmented, about as long as first exopodal segment, proximal half bulbous, distal part tapering to acuminate point and curved inwards and ornamented with three or four small spinules at about mid-length of outer margin ( Figure 10E View Figure 10 ).
Leg 5 ( Figure 8B, C View Figure 8 ) without inter coxal sclerite; elongate trapezoidal plate, ornamented with longitudinal row of moderately large, almost equal spinules along inner margin and one small cuticular pore proximally; inner spiniform process horn-like, with acuminate tip, reaching almost distal-third of next segment, distal margin oblique, armed with four setae. Outermost seta long, articulate at base and arising from small outer lobe; one small spiniform seta (probably ancestral exopodal seta) on small lobe; another two unequal setae on inner lobe, outer seta 1.2 times as long as innermost seta.
Leg 6 ( Figure 8B View Figure 8 ) smooth, unarmed, forming simple operculum covering gonopore, fused with somite; elliptical plate-like structure in ventral view.
Description of adult female
Body length, excluding caudal setae, 255–350 μm (260 μm in allotype). Habitus ( Figure 11A, B View Figure 11 ) similar to male in ornamentation of prosomites, colour, etc., but genital somite and first abdominal somites fused into double-somite and habitus slightly stronger. Genital complex rectangular, occupying anterior ventral half ( Figure 12A View Figure 12 ); single genital aperture and median copulatory pore covered by vestigial sixth legs; seminal receptacles small, hard to distinguish from internal tissue and gut content; copulatory duct very short and weakly sclerotised. Preanal somite and anal somite very similar to male.
Caudal rami ( Figures 11A–C View Figure 11 , 12B View Figure 12 ) similar to those of male in relative proportions.
Antennule ( Figure 9B View Figure 9 ) seven-segmented, ornamented on first segment with few minute spinules; aesthetasc on fourth segment slender, constricted at about midlength, overreaching ultimate segment; apical aesthetasc on seventh segment longer than its segment and fused basally to two apical setae; setal formula: 0.6.4.4+aes.1.0.8+aes. All setae smooth except unipinnate proximalmost one on second segment. Length ratios of segments, from proximal to distal end and along caudal margin, 1.0:3.4:1.5:2.1:0.6:1.0:2.1.
Antenna, labrum, mandible, maxillule, maxilla and maxilliped similar to those of male.
Leg 1 ( Figure 13A View Figure 13 ) coxa trapezoidal, unarmed, ornamented with one row of spinules near mid-distal margin; basis trapezoidal, armed with only one outer seta, and ornamented with one row of spinules each at base of exopod and endopod; armature and ornamentation of exopod and endopod similar to those of male.
Leg 2 ( Figure 13B View Figure 13 ) exopod similar to that of male. Endopod spatulate, 3.8 times as long as wide, 0.4 times as long as first exopodal segment; other details same as in male.
Leg 3 ( Figure 13C View Figure 13 ) coxa with arched row of spinules near distal margin. Basis trapezoidal, ornamented with one pore anteriorly and one row of spinules at outer distal angle and armed with long, basally articulate, smooth outer seta. Exopod two-segmented, either segment ornamented with one row of spinules along outer margin, as illustrated, and with hyaline frill at inner distal corner; first segment armed with outer spine; second segment with outer spine and apical strong seta; seta 3.6 times as long as spine; all armature elements bipinnate. Endopod spiniform, 1.9 times as long as first exopodal segment, smooth, and tapering to acuminate point.
Leg 4 ( Figure 13D View Figure 13 ) exopod similar to that of male; endopod straight, somewhat spiniform, 0.7 times as long as first exopodal segment, tapering to acuminate point, with transverse row of spinules at midlength.
Leg 5 ( Figure 13E View Figure 13 ) ornamented with one small pore; inner margin smooth; spiniform process at inner distal corner shorter than in male; armature as in male.
Leg 6 ( Figure 12A View Figure 12 ) vestigial, fused into simple cuticular flap, covering gonopore.
Distribution
This species is only known from the type locality.
Ecology
The new species was accompanied on different occasions by Nitocrella sp. , and Haplocyclops fi ersi Karanovic and Ranga Reddy 2005 ( Copepoda), Indocandona nagarjuna Karanovic and Ranga Reddy 2008 (Ostracoda) , Habrobathynella nagarjunai Ranga Reddy 2002 (Bathynellacea) , Andhracoides sp. (Isopoda) , Bogidiella indica Holsinger, Ranga Reddy and Messouli, 2006 (Amphipoda) , and unidentified nematodes and mites.
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.