Anzcyclops indicus, Totakura, Venkateswara Rao & Reddy, Yenumula Ranga, 2015

Totakura, Venkateswara Rao & Reddy, Yenumula Ranga, 2015, Groundwater cyclopoid copepods of peninsular India, with description of eight new species, Zootaxa 3945 (1), pp. 1-93 : 62-72

Anzcyclops indicus n. sp.

( Figs. 38–44 )

Type locality. River Krishna (water temperature 24°C; pH 7.0) at Madipadu village (16°48′50′′N 80°04′22′′E, elevation 40 m) in Guntur District, Andhra Pradesh, South India ( Fig. 1 ).

Type material examined. Holotype female (MNHN-IU-2013-11870) and allotype male (MNHN-IU-2013- 11871), dissected on 3 slides each; 45 paratypes: 2 females, dissected on 3 slides each (MNHN-IU-2013- 11872–11873), 2 females (MNHN-IU-2013-11874–11875) and 1 male (MNHN-IU-2013-11876), whole-mounted on 1 slide each, and 4 males and 37 females in alcohol in a vial (MNHN-IU-2013-11877); 12 October 2008; Coll. V. R. Totakura.

Other material examined. South India, Andhra Pradesh, Guntur District, River Krishna at Taduvayi village (16°45′32.3′′N 80°07′35.8′′E; elevation 31 m; water temperature 27°C; pH 7.0), 27 July 2008: 1 male and 1 female at Challagariga village (16°45′32′′N 80°07′35′′E; elevation 39 m; water temperature 32°C; pH 7.5), 78 km from type locality, 12 October 2008: 1 male and 3 females; 23 November 2008: 3 males and 4 females; at Chamarti village (16°34′56.0′′N 80°16′31.7′′E; elevation 39 m; water temperature 28°C; pH 7.5), 27 July 2008: 4 females only; at Ramannapeta village (16°34′06.0′′N 80°46′11.6′′E; elevation 39 m; water temperature 28°C; pH 7.5), 7 km from type locality, 27 July 2008: 2 females only; Coll. V. R. Totakura & P. Kondala Rao.

Farm bore (water temperature 28°C; pH 7.5) at Chintapalli village (16°45′32′′N 80°07′35′′E; elevation 39 m), 0 3 July 2008: 1 male and 4 females; Coll. V. R. Totakura.

Diagnosis. Very small cyclopinae, total body length of females 241–282 Μm and of males 249–273 µm; greatest width in posterior half of cephalothorax; body length/width ratio in dorsal view 2.4–2.8 in females and 2.5 in males; cephalothorax 1.9 times as wide as genital double-somite in females; hyaline fringes of all somites narrow and smooth; genital double-somite with somewhat inflated anterior part but without lateral recesses, about as long as wide in dorsal view; caudal rami 1.4 times as long as wide and armed with six setae; female antennule 10-segmented, second and fourth segments with 6 and 1 seta(e), respectively; male antennule 15-segmented and digeniculate; antenna 4-segmented, without exopodal seta, with armature formula 1.2.5.6; mandibular palp represented by 2 long plumose setae; maxilla 5-segmented, with armature formula 2.3.3.2.3; maxilliped 4- segmented, armature formula 2.2.1.2; spine and setal formulae of second exopodal segment of legs 1–4: 2.3.3.2, and 5.4.4.4, respectively; intercoxal sclerite with concave distal margin and without any surface ornamentation; all legs with inner coxal seta; leg 1 basis without inner spine and first exopodal segment unarmed; second endopodal segment of leg 4 about 1.4 times as long as wide, armed with 1 apical spine and 3 inner setae. Leg 5 1-segmented, quadriform, armed with 2 unequal setae apically; leg 6 with 2 elements.

Description of adult female. Total body length, measured from base of rostrum to posterior margin of caudal rami (excluding caudal setae), 248 Μm. Preserved specimens colourless. Naupliar eye absent. Body ( Fig. 38 a, b) somewhat dorso-ventrally compressed, with prosome/urosome ratio 1.5 and greatest width at posterior end of cephalothorax (122 Μm). Body perforated, length/width ratio 2.4. Cephalothorax 1.9 times as wide as genital double-somite. Rostral projection ( Fig. 40 a) moderately developed, broadly triangular, furnished with 2 dorsal sensilla. Free pedigerous somites 2–4 with rounded postero-lateral corners. Pseudosomite present between prosome and urosome. Cephalothorax ( Fig. 38 a) as long as its greatest width and 41.6% of total body length; ornamented with several small sensilla, with slightly developed, smooth, mid-dorsal hyaline fringe; no other ornamentation discernible. Fifth pedigerous somite about as wide as genital double-somite and with somewhat pronounced, pointed postero-lateral angles, with narrow, smooth hyaline fringe dorsally and ventrally, and ornamented with 4 dorsal sensilla ( Fig. 39 a). Genital double-somite about as long as wide, maximum width at about proximal third and somewhat narrow behind; hyaline fringe of genital somite and next 2 somites smooth on dorsal and ventral surfaces. Seminal receptacle ( Fig. 39 b) composed of anterior and posterior parts, anterior part slightly larger, with both external margins rounded; copulatory duct short and straight; ovipores crescentic, covered by sixth legs ( Fig. 39 a–c). Anal somite ( Figs. 38 a, 39a–b) ornamented with transverse row of long spinules on ventro-lateral posterior margin, 2 small, dorsal sensilla and 1 proximo-lateral pore ( Fig. 39 c). Anal operculum ( Fig. 39 a, c) moderately developed, convex, 53.3% of somite’s width, not reaching posterior margin of somite and fringed with a row of fine spinules along posterior margin. Anal sinus narrow, without apparent ornamentation.

Caudal rami ( Fig. 39 a–c): parallel and close to each other and 0.8 times as long as anal somite; each ramus 1.4 times as long as maximum width, sub-proximally dilated on inner margin and with 1 row of small spinules on postero-ventral margins; similar spinules also occurring at base of outermost apical setae at inner distal corners. Dorsal seta 0.8 times as long as principal outer apical seta, inserted at distal fifth of ramus length, and biarticulate at base. Lateral seta arising from dorsal surface close to outer margin at 3/5 of ramus length and 0.7 times as long as maximum width of ramus. Outermost apical seta spiniform, about as long as ramus, inserted subapically. Innermost apical seta slender, 0.4 times as long as of outermost apical seta. Principal apical setae without breaking planes. Outer seta 5 times as long as outermost apical seta, 0.4 times as long as urosome. All setae plumose.

Antennule ( Fig. 40 b): strong, 10-segmented, extending up to 4/5 of cephalothorax, ornamented with 1 row of spinules on first segment. Setal formula: 7.6.2.1.3.2.2+aes.3.2.7+aes. Segments 1, 2, 5, 6, 7, 9 and 10 with 1, 2, 1, 1, 1, 1 and 5 long plumose setae, respectively. Length ratios of antennular segments along medial axis: 1.0: 0.6: 0.2: 0.1: 0.4: 0.4: 0.5: 0.3: 0.4: 0.5. Probable segmental homology: 1 (I–V), 2 (VI–XI), 3 (XII–XIII), 4 (XIV), 5 (XV–XVI), 6 (XVII–XX), 7 (XXI–XXIII), 8 (XXIV), 9 (XXV), 10 (XXVI–XXVIII).

Antenna ( Fig. 40 c) 4-segmented; consisting of coxobasis and 3-segmented endopod. Coxobasis 1.8 times as long as wide, armed with 1 seta at inner distal corner; exopodal seta absent. First endopodal segment 1.4 times as long as wide, armed with 2 setae, ornamented with row of long spinules on outer margin. Second segment 1.5 times as long as maximum width and armed with 1 seta on inner distal margin ventrally, 2 setae at inner distal corner; 2 setae on distal margin; ornamented with 1 row of spinules at outer distal margin. Third segment 1.8 times as long as wide, ornamented with 2 spinular rows on outer margin and armed with 6 unequal, apical setae.

Labrum ( Fig. 40 d): trapezoidal; anterior edge almost straight, with 18 tiny, blunt, equal teeth between blunt, rounded lateral corners; ornamented with elongate hair-like spinules on dorsal surface.

Mandible ( Fig. 40 e–g): coxal gnathobase roughly divided into 3 groups of teeth; inner group of 3 large unequal teeth, innermost one being larger; middle group of 3 moderate teeth and a small sub-distal spinular row; distal group with 1 pinnate outermost seta and 2 long spinules on ventral surface. Palp represented only by 2 equal plumose setae.

Paragnaths ( Fig. 41 a): conical, with serrulate lateral margins.

Maxillule ( Fig. 41 b): composed of praecoxa and 2-segmented palp. Praecoxal arthrite bearing 3 very strong claw-like spinous processes and 1 stout pinnate seta and 6 medial elements; second proximalmost seta largest, pinnate. Palp composed of coxobasis and endopod. Coxobasis with smooth proximal (exopodal) seta and 3 medial setae (2 smooth and 1 plumose), smooth medial setae of about same length; endopod with 2 apical and 1 subapical setae.

Maxilla ( Fig. 41 c): 5-segmented, consisting of praecoxa, coxa, basis and endopod. Proximal endite of praecoxa robust, armed with 2 unequal setae (1 plumose, 1 simple); distal endite small, unarmed. Proximal endite of coxa with 1 bipinnate seta; distal endite mobile, elongate and armed with 2 plumose, equal, apical setae; coxa unornamented. Basis expanded into robust claw, ornamented with 1 row of spinules along inner margin and armed with 2 setae, 1 small seta at base; strong seta 0.9 times as long as claw and pinnate. Endopod 2-segmented; proximal segment armed with 1 robust claw and 1 bipinnate seta, which is slightly shorter; distal segment small, with 1 robust, unipinnate, apical claw and 2 slender and smooth subapical setae. All strong setae and basal claw prehensile.

Maxilliped ( Fig. 41 d): 4-segmented; composed of syncoxa, basis and 2-segmented endopod; syncoxa 1.4 times as long wide; basis 1.6 times as long as maximum width. Setal formula 2.2.1.2; all setae bipinnate except 1 smooth seta on basis.

Legs 1–4 ( Fig. 42 a–d): 2-segmented exopod and endopod; endopod only slightly shorter than exopod on all legs. Leg 1 shorter than others and its second exopodal segment subspherical or oval in outline, bearing 5 setae, but 4 setae on other legs. Intercoxal plates with small, rounded, unornamented prominences on all legs. Hairs present on inner corner of basis, and also along margins of exopod and endopod, as illustrated. Outer seta on basis of leg 1 as long as exopod; same seta on legs 2–4 much shorter. Leg 1 without outer spine on first exopodal segment. On all legs, coxa armed with seta and unornamented and without inner spine on basis; first exopodal segment without inner seta. Leg 4 endopod about as wide as exopod, 1.4 times as long as it own width, as long as inner seta and twice as long as apical spine The spine formula of second exopodal segment of legs 1–4: 2.3.3.2; setal formula: 5.4.4.4. Spine and setal formulae of legs 1–4 (legend: same as that of Paracyclopina orientalis ):

Coxa Basis Exopod Endopod

1 2 1 2

Leg 1 1-0 0-1 0-0 3, 2+ II 1 -0 1, 1+I, 1 Leg 2 1-0 0-1 0- I 3, 1+I, II 1 -0 2, 1+I, 1 Leg 3 1-0 0-1 0- I 3, 1+I, II 1 -0 2, 1+I, 1 Leg 4 1-0 0-1 0- I 3, 1+I, I 1 -0 2, 1+I, 1 Leg 5 ( Fig. 39 a–c): composed of protopod completely fused to somite and free exopod. Protopodal seta moderate in size and plumose; exopod small, 1-segmented, slightly longer than wide, with 2 apical unequal simple setae, inner seta being longer.

Leg 6 ( Fig. 39 c): small cuticular plate; bearing 2 tiny spines.

Description of adult male. Total body length excluding caudal setae 256 Μm. Habitus ( Fig. 43 a) slenderer than female. Prosome/urosome ratio 1.6, greatest width (109 Μm) at posterior end of cephalothorax. Body length/ width ratio 2.5. Cephalothorax 1.9 times as wide as genital somite and representing 38.6% of total body length. Free pedigerous somites gradually narrowing, with slightly produced, pointed postero-lateral corners. Hyaline fringes on all somites narrow and smooth. Fifth pedigerous somite with oblique lateral margins and 0.8 times as wide as genital somite. Genital somite 1.4 times as wide as long. Anal somite and operculum as in female.

Caudal rami ( Fig. 44 a–c): similar to female, 15.2% longer than anal somite; each ramus 1.4 times as long as maximum width. Armature and ornamentation almost as in female; innermost seta somewhat longer.

Antennule ( Fig. 43 b, c): 15-segmented, digeniculate; proximal geniculation between segments 9 and 10 and distal geniculation between segments 11 and 12. Setal formula: 9+2aes.4.1+aes.0.1aes.1+aes.0.0.0.0.1.0.1aes. 2.9+aes. Length ratios of antennular segments along medial axis: 1.0: 0.4: 0.2: 0.4: 0.4: 0.2: 0.6: 0.3: 0.6: 0.5: 1.2: 0.9: 1.3.

Antenna, labrum, mandible, maxillule, maxilla, maxilliped, and legs 1-5 similar to those of female.

Leg 6 ( Fig. 44 a–c): both legs partly fused basally; each leg large, cuticular plate-like, armed with 2 unequal, simple setae and reduced spinous projection.

Variation. Sometimes apical spine on second endopodal segment of leg 4 is apically curved inwards or outwards ( Fig. 42 e, f).

Etymology. The specific epithet, indicus , refers to the occurrence of this species in India and denotes the first description of this new species of the genus Anzcyclops from the Indian subcontinent; derived from the root indic; gender masculine.

Distribution. The new species is known only from type locality.

Ecology. The new species was collected on several occasions in the hyporheic zone of the River Krishna and only once in riparian farm bore, just about 500 m from the river bank. It co-occurred with several other taxa in different localities. It co-existed with Atopobathynella operculata Ranga Reddy & Schminke , Habrobathynella vaitarini Ranga Reddy & Totakura , Parastenocaris curvispinus Enckell , Folioquinpes chathamensis (Sars) , ostracods, mites, amphipods, and oligochaetes, cyclopoids, Parastenocaris sp., and other unidentified harpacticoids at the type locality; Habrobathynella plenituda Ranga Reddy & Schminke , Habrobathynella sp., P. curvispinus , ostracods, and oligochaetes at Ramannapeta; only with P. curvispinus at Taduvayi; with P. curvispinus, Serbanibathynella secunda Totakura & Ranga Reddy, mites, and oligochaetes at Chamarti; with H. vaitarini ; H. schminkei Ranga Reddy , H. plenituda , Atopobathynella sp., Kinnecaris godavari Ranga Reddy & Schminke , P. curvispinus , mites, nematodes, oligochaetes, ostracods, and chironomid larvae at Challagariga; with Habrobathynella sp., P. curvispinus , amphipods, nematodes, cladocerans, insect larvae in a farm bore.

Remarks. The genus Anzcyclops was established by Karanovic, Eberhard & Murdoch, (2011 with the Anzcyclops yarriensis Karanovic, Eberhard & Murdoch, 2011 as its type species and four other congeners, all from Australia and New Zealand (see Karanovic, Eberhard & Murdoch 2011). Anzcyclops indicus n. sp., which is the first record of Anzcyclops from Asia, fulfills most of the principal generic criteria. For example, legs 1–4 relatively are short, with 2-segmented rami; endopods are only slightly shorter than exopods; all legs are without inner seta on first exopodal segment, and the spine formula of the second exopodal segment is 2.3.3.2; second exopodal segment of leg 1 subspherical or oval in outline, bearing five setae, but four setae on other legs; the second endopodal segment of leg 4 has a single apical spine and three setae; leg 5 exopod is small, somewhat quadrate and armed apically with two small setae, and the protopodal seta is plumose and of moderate size and; leg 6 has two elements. Also, the body is dorsoventrally flattened and somewhat primitively cyclopiform; antennule is 10- segmented; and the overall structural and armature details of antenna to maxilliped closely conform, if not identical, to what obtains in Anzcyclops . However, A. indicus n. sp. differs from all its known congeners in other respects: body length is 241–282 µm vs. 304-500 µm; anal is operculum short, convex and finely serrulate vs. long, linguiform and smooth; antennal armature formula 1.2.5.6 vs. 2.1.6(5).7; the remnant of the mandibular palp is not discernible vs. distinctly seen; maxillary armature formula 2.3.3.2.3 vs. 2.3.2.2.3; maxilliped armature formula 2.2.1.2 vs. 2(0).2(1).1.2; leg 1 basis without vs. with inner spine, first exopodal segment without vs. with outer spine, and second endopodal segment with two vs. three inner setae. And yet, we think that it would not be advisable at this juncture to establish a separate genus for the new species based on these apparently trivial differences. It is hardly unlikely that future investigations in other parts of the peninsular India would bring to light several other allied species when it would be more appropriate to critically evaluate the generic position of the new species.

Compared with the four Western Australian species, viz. Anzcyclops ballensis Karanovic, Eberhard & Murdoch, 2011 , A. yarriensis Karanovic, Eberhard & Murdoch, 2011 , A. belli Karanovic, Eberhard & Murdoch, 2011 , and A. euryantennula Karanovic, Eberhard & Murdoch, 2011 , and also to A. silvestris (Harding, 1958) from Australia and New Zealand, A. indicus n. sp. displays somewhat closer morphological kinship with A. ballensis by possessing identical number of antennular segments in both sexes (in females, segment 2 long being fused with the next segment; segment 6 with 3 setae), and also the same armature details on legs 2 and 3. However, A. indicus n. sp. can be easily distinguished from A. ballensis , inter alia, by dorso-ventrally compressed vs. normal body; moderately developed vs. large anal operculum; two setae vs. none on the first segment of maxilliped; six setae vs. seven setae on distal segment of antenna; proximally only slightly dilated vs. distinctly dilated genital doublesomite; dorsal seta longer vs. shorter than caudal rami; and outer seta on second endopodal segment of leg 4 present vs. absent.

By having unarmed proximal exopodal segment on leg 1, the new species is close to the Indian Haplocyclops (Kiefercyclops) fiersi Karanovic & Ranga Reddy, 2005 and Haplocyclops godavari n. sp. — perhaps a case of convergent evolution. Likewise, the new species lacks the inner spine on leg 1 basis as in the case of Haplocyclops and Rybocyclops .

Figures

FIGURE 1. Map showing the type localities of the cyclopoid species on the Indian peninsula.

FIGURE 38. Anzcyclops indicus n. sp., paratype female. (a) habitus, dorsal; (b) same, lateral.

FIGURE 39. Anzcyclops indicus n. sp., holotype female (a), paratype female (b, c). (a) urosome, dorsal; (b) same, ventral; (c) same, lateral.

FIGURE 40. Anzcyclops indicus n. sp., holotype female (a – e), paratype (f, g). (a) rostrum, ventral; (b) antennule, lateral; (c) antenna, lateral; (d) labrum, ventral; (e) mandible, lateral; (f, g) same, coxal gnathobase.

FIGURE 41. Anzcyclops indicus n. sp., holotype female. (a) paragnaths, latero-ventral; (b) maxillule, lateral; (c) maxilla, lateral; (d) maxilliped, lateral; (e) leg 6, dorsal.

FIGURE 42. Anzcyclops indicus n. sp., holotype female (a – d), paratype female (e, f). (a) leg 1, anterior (arrow pointing to lack of outer spine); (b) leg 2, posterior; (c) leg 3, anterior; (d) leg 4, anterior; (e, f) apical spine on leg 4.

FIGURE 43. Anzcyclops indicus n. sp. (a) paratype male, habitus, dorsal; (b) allotype male, antennule, lateral; (c) same, penultimate and ultimate segments.

FIGURE 44. Anzcyclops indicus n. sp., allotype male (a, b), paratype male (c). (a) urosome, dorsal; (b) same, ventral; (c) same, lateral.