Haplocyclops (Kiefercyclops) primitivus, 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 : 72-81

Haplocyclops (Kiefercyclops) primitivus n. sp.

( Figs. 45–50 )

Type locality. River Godavari , Kapileswarapuram village (16°47′09.0′′N 82°03′39.3′′E; elevation 23 m; water temperature 28ºC, pH 7.0) in East Godavari District, Andhra Pradesh, South India ( Fig. 1 ).

Type material examined. Holotype female (MNHN-IU-2013-11878) and allotype male (MNHN-IU-2013- 11879), dissected on 3 slides each, and 6 paratypes: 1 female, dissected on 3 slides (MNHN-IU-2013-11890); 2 females whole-mounted on 1 slide each (MNHN-IU-2013-11891–11892), 1 male and 1 female in alcohol in 1 vial (MNHN-IU-2013-11893); 2 females in senior author’s personal collection. 20 July 2008, Coll. V. R. Totakura.

Other material examined. South India, Andhra Pradesh, East Godavari , River Godavari at Atreyapuram village (water temperature 28ºC, pH 7.0), 20 July 2008: 1 male and 3 females; at Dhawaleswaram village (water temperature 27ºC, pH 7.5), 20 July 2008: 2 females in senior author’s personal collection; Coll. V. R. Totakura.

Diagnosis. Very small cyclopinae, cyclopiform and integument smooth. Genital double-somite large and of characteristic shape, swollen both laterally and ventrally, with genital field situated at 3/4 of genital doublesomite’s length; anal operculum bowl-shaped, extending up to or beyond the somite’s limit; caudal rami about 1.5–1.7 times as long as wide, with lateral seta inserted in proximal half almost dorsally; ornamented with transverse row fine spinules at the base of lateral seta and dorsal seta; principal inner apical seta 1.3 times as long as principal outer apical seta; female antennule 11-segmented, lateral seta present on ultimate segment, and with only 2 setae on seventh segment; male antennule 16-segmented, digeniculate; antenna 4-segmented, with setal formula 2.1.5.7 and without exopodal seta; mandibular palp lacking; maxillulary palp 2-segmented; maxilla 4- segmented, with small lateral seta on basis; and maxilliped 4-segmented, setal formula 1.2.1.2; 2-segmented exopod and endopod on legs 1–4, without any coxal armature; leg 1 basis without inner spine; spine formula of second exopodal segment of legs 1–4: 2.2.2.2 and setal formula: 5.4.4.4; endopod of leg 4 with 1 spine and 1 seta apically; leg 5 represented by 3 setae, of which 2 setae on small protuberance and 1 basal plumose seta; female leg 6 as distinct cuticular plate, armed with 2 unequal setae and 1 tiny spinous process; the same leg in male with 2 minute spinous processes and 1 slender seta.

Description of adult female. Total body length, measured from tip of rostrum to posterior margin of caudal rami (excluding caudal setae), 318–347µm (holotype 338 µm). Habitus ( Fig. 45 a) robust, cyclopiform and dorsoventrally compressed, with prosome/urosome ratio 1.5 and greatest width (102 Μm) at distal end of cephalothorax. Body length/width ratio about 3.4 (dorsal view); cephalothorax almost 1.5 times as wide as genital double-somite.

Free pedigerous somites without particular expansions, lateral margins somewhat curved. Preserved specimens colourless. Naupliar eye absent. Rostral projection ( Fig. 47 a) well developed, membranous, broadly triangular, tip rounded and furnished with 2 large sensilla. Cephalothorax ( Fig. 45 a) 1.7 times as long as greatest width (dorsal view) and 35.7% of total body length; pleurotergites of free pedigerous somites ornamented with small sensilla; no other ornamentation visible. Hyaline fringes of prosomites narrow and smooth. Arthrodial membranes well developed. Third pediger longer than fourth one, fourth pediger unornamented. Fifth pediger ( Fig. 46 a) ornamented with 4 small dorsal sensilla; hyaline fringe smooth dorso-ventrally. Genital double-somite ( Fig. 46 a–c) proximally expanded, large, about as wide as long (dorsal view) and ornamented with 2 large dorsal sensilla; hyaline fringe of genital double-somite as well as next 2 urosomites smooth. Copulatory pore ( Fig. 46 b) small, ovoid, situated at 3/4 of somite’s length; copulatory duct narrow, well sclerotized. Seminal receptacle with large anterior expansion but somewhat narrow behind, representing 61.5% of double-somite’s length; oviducts broad and weakly sclerotized. Ovipores situated dorso-laterally, covered with reduced sixth legs. Anal somite ornamented with 2 large sensilla dorsally and 1 transverse row of minute spinules along posterior margin ventrally and laterally. Anal operculum large, bowl-shaped/sublinguiform, extending slightly beyond somite’s limit, smooth, with almost straight caudal margin, representing 65.3% of anal somite’s width. Anal sinus somewhat wide.

Caudal rami ( Fig. 46 a–c): subcylindrical, parallel, 1.5 times as long as wide; ornamented with a row of spinules on subdistal dorsal surface close to dorsal seta. Dorsal seta about 1.9 times as long as ramus, inserted at 4/ 5 of ramus and just above the level of outermost apical seta, biarticulate at base ( Figs. 45 a, 46a–c). Lateral seta arising somewhat dorso-laterally at 3/5 of ramus length, 0.7 times as long as ramus width; 1 short transverse row of fine spinules lying beside its base. Outermost apical seta slightly longer than ramus. Innermost apical seta small and slender, 0.4 times as long as outermost apical seta. Principal apical setae without breaking planes. Inner apical seta 3.3 times as long as caudal rami, 1.3 times as long as outer apical seta. All setae plumose.

Antennule ( Fig. 45 b): 11-segmented, 73.6% of the length of cephalothoracic shield and unornamented; armature formula: 7.2.5.2.1.2.2.3.3.3.7+aes. Setae articulating at basal part on segments 7, 8, and 11, and segments 1, 3, 7, 8, 10, and 11 with 4, 1, 2, 1, 1, and 3 long bipinnate setae, respectively; all other setae smooth. Length ratios of antennular segments from proximal end and along caudal margins 1.0: 0.2: 0.5: 0.2: 0.1: 0.3: 0.5: 0.5: 0.3: 0.4: 0.5. Probable segmental homology: 1 (I–V), 2 (VI–VII), 3 (VIII–XI), 4 (XII–XIII), 5 (XIV), 6 (XV–XVI), 7 (XVII–XX), 8 (XXI–XXIII), 9 (XXIV), 10 (XXV), and 11 (XXVI–XXVIII).

Antenna ( Fig. 47 b): 4-segmented, comprising coxobasis and 3-segmented endopod. Coxobasis large, somewhat cylindrical, 2.5 times as long as wide, armed with 2 short, smooth seta at inner distal corner; exopodal seta absent. First endopodal segment stout, 1.3 times as long as wide, with inner smooth seta, and 1 arched row of spinules on outer margin. Second endopodal segment about twice as long as wide, bearing 5 setae and ornamented with 1 spinular row on outer distal margin. Third endopodal segment cylindrical, 2.6 times as long as wide, armed with 7 smooth, prehensile apical setae, and ornamented with 1 spinular row on outer distal margin.

Labrum ( Fig. 47 c): relatively small, trapezoidal plate; anterior edge slightly concave, with about 20 small blunt teeth between rounded lateral corners; ornamented with 2 groups of long hair-like spinules on dorsal surface.

Mandible ( Fig. 47 d): 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 1 small sub-distal spinular row; distal group with 2 long spinules on ventral surface and 1 unipinnate outermost seta.

Maxillule ( Fig. 47 e): composed of praecoxa and 2-segmented palp. Praecoxal arthrite bearing 3 very strong claw-like spinous processes and 1 stout pinnate seta and 7 medial elements, of which second proximal one largest and pinnate. Palp composed of coxobasis and endopod. Coxobasis with smooth proximal (exopodal) seta and 3 medial setae (2 slender, smooth and 1 strong, bipinnate); endopod with 3 smooth (2 apical and 1 subapical) setae.

Maxilla ( Fig. 47 f): 4-segmented, consisting of syncoxa, basis and 2-segmented endopod; praecoxa fused to coxa; proximal endite of praecoxa robust, armed with 2 setae; distal endite small, unarmed. Proximal endite of coxa with 1 bipinnate seta; distal endite fused at base, moderate in size, elongate and armed apically with 2 unequal pinnate setae, proximal seta being 1.2 times longer; syncoxa unornamented. Basis expanded into robust claw, armed with 2 setae; 1 small seta at base and 1 strong pinnate proximal seta about as long as claw. Endopod 2- segmented; proximal segment armed with 2 robust, unequal, bipinnate setae; 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. 47 g): 4-segmented, composed of syncoxa, basis and 2-segmented endopod. Armature formula: 1.2.1.2. Ornamentation consisting of longitudinal rows of spinules on first 3 segments.

Legs 1–4 ( Fig. 48 a–d): relatively short, with 2-segmented exopod and endopod. Endopod only slightly shorter than exopod on legs 1–3, but distinctly reduced in size on leg 4. Armature formula of legs 1–4 (legend: same as that of Paracyclopina orientalis ):

Coxa Basis Exopod Endopod

1 2 1 2

Leg 1 0-0 0-1 0- I 4, 1+I, I 1 -0 1, 1+I, 1 Leg 2 0-0 0-1 0- I 3, 1+I, I 1 -0 1, 1+I, 1 Leg 3 0-0 0-1 0- I 3, 1+I, I 1 -0 2, 1+I, 1 Leg 4 0-0 0-1 0- I 3, 1+I, I 1 -0 1+I Second exopodal segment spine formula 2.2.2.2 and setal formula 5.4.4.4. Apical spine on second endopodal segment of legs 1–3 about as long as segment, but distinctly longer on leg 4. Intercoxal sclerites of all swimming legs with concave distal margins and rounded lateral prominences fringed with long hairs. Praecoxae short, narrow and ornamented with 1 row of spinules each at outer distal margin. All coxae ornamented with 1 row of spinules each at outer distal margin. Basis with round inner distal corners, ornamented with long hairs. Inner spine on basis of leg 1 absent. Second endopodal segment of leg 4 as long as wide, armed with 1 spine and 1 seta apically; first segment ornamented with a row of spinules on distal margin ( Fig. 47 d).

Leg 5 ( Figs. 45 a, 46a–d): with 3 setae, basipodal seta strong, visible clearly in dorsal and lateral views, arising from prominent protuberance; other 2 setae unequal, smooth and located on small protuberance; 1 row of spinules occurring at base of protuberance.

Leg 6 ( Fig. 46 e): distinct at base, small, semicircular cuticular plate, armed with 2 unequal, spiniform setae and 1 small spinous projection; outer seta about 1.5 times as long as inner one.

Description of adult male. Total body length 338 µm. Habitus ( Fig. 49 a) slightly slenderer than in female, prosome/urosome ratio about 1.5 and greatest width (96 Μm) at posterior end of cephalothorax. Body length/width ratio 3.6; cephalothorax about 1.7 times as wide as genital somite. Cephalothorax 1.2 times as long as wide (dorsal view) and 35.2% of total body length. Ornamentation of prosomites as illustrated. Hyaline fringe of fifth pedigerous somite smooth both ventrally and dorsally. Genital somite ( Fig. 50 a, b) about as long as wide, with smooth hyaline fringe dorsally, ornamented with 2 sensilla dorsally; 2 relatively small, ovoid spermatophores visible from inside; next 3 urosomites without any sensilla, integument ornamented only with smooth hyaline frill. Anal somite with transverse row of spinules all along caudal margin. Anal operculum almost similar to female.

Antennule ( Fig. 49 b, c): 16-segmented, digeniculate, proximal geniculation between 8 and 9 and distal geniculation between 14 and 15 segments; ornamented with spinules only on first segment. Armature formula: 10.3.3.1.0.1.0.0.1+aes.2.1.1.1.0.1.10. Short unipinnate seta present on segment 13; segments 1, 6 and 16 with 1, 1 and 4 long pinnate seta(e), respectively. Aesthetascs on segments 4 and 9 smooth and of moderate length; 4 setae on segment 16 with articulate base. Length ratios of antennular segments along medial axis 1.0: 0.3: 0.2: 0.1: 0.1: 0.1: 0.2: 0.3: 0.3: 0.2: 0.3: 0.2: 0.3: 0.7: 0.7: 1.2.

Antenna, labrum, mandible, maxillule, maxilla, maxilliped, legs 1–3 and 5, and caudal rami similar to those of female.

Leg 4 ( Fig. 48 f): second endopodal segment about as long as wide, with 1 apical seta, 1 apical spine and 1 inner seta; otherwise as in female.

Leg 6 ( Fig. 50 b): large, unornamented cuticular plate fused at base; armed with 1 seta and 2 diminutive prominences on outer distal corner, as in female.

Etymology. The specific epithet is derived from the Latin adjective, primitivus , alluding to several plesiomorphic character states. Gender masculine.

Variation. Second exopodal segment of leg 3 with additional inner seta ( Fig. 48 e), second endopodal segment of leg 4 with additional inner seta ( Fig. 48 f).

Ecology. The new species was found in very small numbers in the present samples. It was, however, accompanied by various taxa at the type locality: Parvulobathynella distincta Ranga Reddy, Elia & Totakura, Habrobathynella plenituda Ranga Reddy & Schminke , and Kinnecaris godavari Ranga Reddy & Schminke ; and at Atreyapuram, it co-existed with Serbanibathynella secunda Totakura & Ranga Reddy, Habrobathynella plenituda Schminke & Ranga Reddy , Habrobathynella savita Ranga Reddy & Totakura , Parastenocaris curvispinus Enckell , oligochaetes, nematodes, and insect larvae

Remarks. Kiefer (1952) erected the genus Haplocyclops Kiefer, 1952 , to accommodate the Madagascan Haplocyclops gudrunae Kiefer, 1952 . Later, Kiefer (1955) added Haplocyclops pauliani Kiefer, 1955 , and Haplocyclops neuter Kiefer, 1955 , from the same region. The description of both these species was repeated by Kiefer himself (1956), but only with some additional drawings. Lindberg (1956) relegated Haplocyclops to a species group in the genus Bryocyclops Kiefer, 1927 . Kiefer (1960a, b) did not completely accept Lindberg’s (1956) decision, but treated Haplocyclops as a subgenus of Bryocyclops , when he described Bryocyclops (Haplocyclops) monodi from the continental Africa. Haplocyclops was considered as subgenus of the genus Bryocyclops by several authors, e. g. Dussart (1981, 1982), Dussart & Defaye (1985), Lescher-Moutoué (1986), Rocha & Carvalho Bjornbberg (1987), and Pesce (1996). The validity of Haplocyclops was accepted by Reid (1999), Dussart & Defaye (2001) and Fiers (2002) after it was critically examined and redefined by Rocha et al. (1998). Finally, six species have so far been recognized under Haplocyclops (see Kiefer 1955, 1960b; Rocha et al. 1998) including the Indian H. (K.) fiersi Karanovic & Ranga Reddy, 2005 , which is, incidentally, the most reduced free-living cyclopoid (see Karanovic & Ranga Reddy, 2005).

Now, the rationale behind assigning H. primitivus n. sp. to Haplocyclops needs to be explained. The new species has the following characters, which are considered by Karanovic & Ranga Reddy (2005) the significant ‘autapomorphies’ of Haplocyclops : the genital double-somite with ovipores situated in the posterior half and the caudal rami with lateral seta inserted in the proximal half. The other supportive characters include: large anal operculum; principal apical setae without breaking planes; seventh antennular segment armed with 2 setae; fifth legs completely fused to somite and represented by 3 slender setae in both sexes. It must, however, be clarified that H. primitivus n. sp. has at least two interesting plesiomorphic character states that are as yet unknown in Haplocyclops : both rami of legs 1–4 are 2-segmented, and the second exopodal segment has a setal formula of 5.4.4.4.

Karanovic & Ranga Reddy (2005) subdivided the genus Haplocyclops into two subgenera: Haplocyclops s. str. Kiefer, 1952 and Kiefercyclops Karanovic & Ranga Reddy, 2005. The former contains seven species, mostly from the Gondwanan landmasses of Madagascar, Africa, and South America whereas the latter heretofore is monotypic with the Indian H. (K.) fiersi . Both H. (K.) primitivus n. sp. and H. (K.) godavari n. sp. described herein belong to the latter subgenus mainly because the mandibular palp is completely absent and the legs 1–4 have no coxal armature. H. primitivus n. sp. has a set of primitive characters, and is thus at variance with H. (Kiefercyclops) diagnosis in the following features: coxobasis of antenna with 2 setae vs. 1 seta; maxillulary palp 2-segmented vs. 1-segmented; maxilla with vs. without lateral small seta on basis; leg 1 first exopodal segment armed vs. unarmed; exopod of leg 3, as well as endopod of legs 2 and 3, 2-segmented vs. 1-segmented; and leg 6 with 2 setae vs. 1 seta. Despite these differences, we think it advisable to allocate H. primitivus n. sp. to Kiefercyclops rather than to Haplocyclops s. str.

H. primitivus n. sp. can be readily separated from both H. (K.) fiersi and H. (K.) godavari n. sp. by the following features: cyclopiform habitus; dorsal caudal seta 1.9 times as long as ramus length; presence of a row of transverse row of fine spinules at base of dorsal seta and lateral seta; lateral seta present on ultimate segment of antennule; leg 1 without spine on basis; legs 1–4 with 2-segmented exopod and endopod; and leg 4 second endopodal segment armed with one spine and one seta (the 1-segmented endopod in H. (K.) fiersi and H. (K.) godavari n. sp. also has similar armature).

Figures

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

FIGURE 45. Haplocyclops primitivus n. sp. (a) paratype female, habitus, dorsal; (b) holotype female, antennule, lateral.

FIGURE 46. Haplocyclops primitivus n. sp., holotype female (a), paratype female (b – e). (a) urosome, dorsal; (b) same, ventral; (c) same, lateral; (d) leg 5, latero-ventral; (e) leg 6, latero-ventral.

FIGURE 47. Haplocyclops primitivus n. sp., holotype female. (a) rostrum, ventral; (b) antenna, lateral; (c) labrum, ventral; (d) mandible, lateral; (e) maxillule, lateral; (f) maxilla, lateral; (g) maxilliped, lateral.

FIGURE 48. Haplocyclops primitivus n. sp., holotype female (a – d), paratype female (e), allotype male (f). (a) leg 1, anterior; (b) leg 2, anterior; (c) leg 3, anterior; (d) leg 4, posterior; (e) endopod of leg 3; (f) endopod of leg 4.

FIGURE 49. Haplocyclops primitivus n. sp. (a) paratype male, habitus, dorsal; (b) allotype male, antennule, lateral; (c) same, ultimate and penultimate segments.

FIGURE 50. Haplocyclops primitivus n. sp. (a) paratype male, urosome, dorsal; (b) allotype male, same, ventral.