Clausidium rodriguesi, Kihara, Terue C. & Rocha, Carlos E. F., 2013

Kihara, Terue C. & Rocha, Carlos E. F., 2013, First record of Clausidium (Copepoda, Clausidiidae) from Brazil: a new species associated with ghost shrimps Neocallichirus grandimana (Gibbes, 1850) (Decapoda, Callianassidae), ZooKeys 335, pp. 47-67 : 48-55

Clausidium rodriguesi sp. n. Figs 1-11

Type material.

Holotype female (reg. no. MZUSP 16464) in ethanol, dissected paratypes consist of 2 females and 2 males (reg. no. MZUSP 19628-19631) undissected paratype consist of 1 female (reg. no. MZUSP 19632) deposited in the collection of the Museu de Zoologia, Universidade de São Paulo, São Paulo, Brazil. All material collected in 02/1984 from the type locality by Prof. Dr. G. Shimizu.

Type locality.

Rio Grande do Norte, Natal, margin of Potengi river (5°45'S, 35°11'W). All specimens from water drawn from the burrows and pleopods of the ghost shrimp Neocallichirus grandimana .

Description.

FEMALE (Figs 1-19, 32-38, 42, 45, 47, 48): Total length, excluding setae on caudal rami, 1.36-1.40mm (N=6). Body cyclopiform (Figs 1, 32-33), maximum width measured at posterior margin of cephalic shield. Prosome twice longer than urosome. First pedigerous somite fused with cephalosome. Body prosomites with minute integumental pits, sensilla and numerous pores distributed as illustrated in Fig. 1. Somites bearing P2-P3 subequal, both with latero-posterior margin sharply drawn out and posterior margin smooth. Somite bearing P4 trapezoid in form, longer than the two anterior somites combined, posterior margin with row of sensilla. Urosome (Figs 1-3, 32-35) 3-segmented, distinctly narrower than prosome. Urosome comprising fifth pedigerous somite, genital double-somite, and anal somite. Somite bearing P5 (Figs 1-2, 32-33) 1.4 times broader than long in dorsal view and with P5 arising ventrolaterally. Genital double-somite (Figs 1-3, 32-33) 1.3 times longer than broad, dorsal and ventro-lateral cuticular ridges marking plane of fusion between genital and first abdominal somite. Genital apertures (Fig. 2) located dorsolaterally on each side, near posterior margin of fifth pedigerous somite. Presence of pairs of pores near genital apertures and medial pore on dorsal view. Ventral surface with pores along medial region (Fig. 3). Egg sacs dorsolaterally located on each side, reaching posterior edge of anal somite and containing 13-15 eggs each. Anal somite (Figs 1-3, 32-33) well developed, formed by second to fourth abdominal somites fused in single somite; dorsal surface with well sclerotized leaf-like areas laterally displaced and intricate folders as illustrated in Figures 2 and 34, clearly incised medially, posterior borders with pointed curved extensions on outer corners; almost quadrate in ventral view, with pointed posterior inner corners and fringed with membrane medially.

Caudal ramus (Figs 2-5) about 3.5 times longer than wide, and armed with 6 setae. Seta I absent, setae II and III slender and naked; setae IV and V strongly developed and bipinnate, plumose on inner edge and spinulose on outer edge (seta V, 2.5 times longer than seta IV); seta VI the shortest; seta VII triarticulate and located at inner posterior corner, both naked. Caudal ramus with rounded lappet on posterior margin of ventral surface covering basal portion of setae III–V.

Rostrum (Fig. 33) incorporated into cephalothorax, demarcated by sclerotized areas laterally; with pair of sensilla ventrally and pattern of pores as illustrated.

Antennule (Fig. 6) 7-segmented. Segment 2 longest, with well-developed pinnate seta inserted on inner distal corner and extending over tip of antennule (arrowed in Fig. 6). Aestethasc inconspicuous, very similar to other setae. Segment 6 with aesthetasc fused basally to seta. Armature formula: I-[5], II-[14 + 1 bipinnate], III-[6], IV-[3], V-[4 + ae], VI-[2 + ae], VII-[7 + ae].

Antenna (Figs 7, 36) 4-segmented. Coxobasis elongated, with row of spinules along inner margin, with single seta on inner distal corner. Endopod 3-segmented; segment 1 with seta along inner margin; segment 2 with 4 setae (2 pinnate and 2 naked); segment 3 with row of spinules along distal margin, 7 apical setae, 2 of them with setules and 2 with spinules.

Labrum (Figs 8, 36, 39-40) twice wider than long; lateral projections with row of denticles. Metastomal area ornamented as in figures 40 and 41.

Mandible (Figs 9-10, 36) well developed. Armed with 3 elements, 1 toothed projection, 1 small seta, and 1 conical structure covered with minute spinules covering inner surface and spines along distal margin.

Maxillule (Figs 11, 36) bilobed, with 1 lateral seta pinnate. Outer lobe with row of spinules along outer margin and 4 setae (2 pinnate and 2 naked). Inner lobe with 3 setae (2 pinnate and 1 naked).

Maxilla (Figs 12, 36) 2-segmented. Syncoxa with 2 bipinnate setae and one stout spine with spinules on distal edge. Basis with large spinous process with spinules along concave margin, bearing 3 setae (2 pinnate and 1 naked) and 1 pinnate spine.

Maxilliped (Figs 13, 36) 4-segmented. Syncoxa with 2 bipinnate setae along inner margin. Basis with 1 pinnate seta and 1 spine with long spinules. Endopod 2-segmented; first segment unarmed; second segment bearing 2 naked lateral setae, 3 pinnate distal setae and stout distal spine with long and slender spinules along inner margin; minute spinules on opposite margin.

P1 (Figs 14-15, 33, 37, 42) biramous, both rami 3-segmented, and highly modified for prehension. Coxa and basis fused forming well-developed segment with row of spines along proximal margin, plumose seta on outer proximal corner; large blade-like seta with acute apex and concentric lines on inner distal corner. Exp-1 and -2 with 1 outer seta each; exp-2 with row of denticles along outer margin. Exp-3 with row of denticles along outer margin, 3 outer setae (2 naked and 1 pinnate), 2 apical setae (outer one pinnate, inner one longest and bipinnate) and 2 inner bipinnate setae. Enp-1 with 1 stout curved process with an adhesive fringe (arrowed in Fig. 14). Enp-2 with pinnate seta. Enp-3 elongated, irregular segment ending in a lobe with serrate margin and armed with 1 seta and 2 sucking discs (Fig. 15); proximal sucking disc 1.6 larger than distal one.

P 2-P4 (Figs 16-18, 33, 38, 47) biramous, with both rami 3-segmented. Coxae with inner plumose seta, row of sparse setules along outer margin and row of spinules along distal margin (P3). Basis of P2-4 longitudinally elongate, with naked seta on outer distal corner, row of spinules along outer margin and row of setules along inner margin. Exp-1 and Exp-2 with row of setules along inner margin and row of spinules (exp-1) or denticles (exp-2) along outer margin, but exp-3 with denticles along outer margin; exopod outer spines serrate and with terminal flagellum (Fig. 48), apical spine with serrate outer margin and spinulose inner margin. Enp-1 and Enp-2 with row of setules along both margins; endopod outer andapical spines serrate and with terminal flagellum, inner apical spines with serrate outer margin and spinulose inner margin (P2-P3) (Figs 16, 17) or both margins serrate (P4) (Fig. 18); sucking discs (Fig. 47, detail in Fig. 49) on distal inner edge of enp-1 and proximal and subterminal inner edges of enp-3.

Armature formula of P2-P4 (Figs 13-16) as follows (Roman numerals representing spines, Arabic numerals representing setae):

P 5 (Figs 2, 19, 33) uniramous, 2-segmented and located laterally on somite. Protopod with 1 outer seta; free exopodal segment elongated with 2 serrate spines, 1 naked seta along outer margin and serrate spine apically; dorsal punctuations as in figures 19 and 33.

P6 (Fig. 2) consisting of 3 small setae.

MALE (Figs 20-31, 39-41, 43, 44, 46): Total length, excluding setae on caudal rami, 0.75-0.79mm (N=4). Body cyclopiform (Fig. 20). Prosome longer than urosome (1.5:1). First pedigerous somite fused with cephalosome. Body prosomites with minute integumental pits, sensilla and numerous pores distributed as illustrated in Figure 20. Cephalosome and 3 free prosomites with posterior borders smooth; somites bearing P2-P3 subequal; somite bearing P4 with distal margin rounder than in female. Urosome (Figs 21-22) 6-segmented, distinctly narrower than prosome. Somite bearing P5 (Fig. 22) 1.5 times broader than long in ventral view and with P5 arising ventrolaterally. Pores and sensilla as illustrated in Figures 21-22. Hyaline frills of first to third abdominal somites finely striated. Anal somite (Figs 21-22) extremely reduced and deeply incised medially, with hyaline frill on dorsal posterior margin.

Caudal ramus (Figs 21-23), antennule, mandible, maxillule and maxilla resembling those of female.

Antenna (Fig. 24) 4-segmented. Coxobasis elongated, with row of spinules along inner margin, with single seta on inner distal corner. Endopod 3-segmented; seta on segment 1 with proximal third enlarged and irregular, inserted along inner margin; segment 2 with row of denticles, 2 naked setae, spinulose spine with terminal flagellum and curved spine with serration along distal inner margin; segment 3 with row of spinules along distal margin, 6 naked setae and 1 curved spine with serration along distal inner margin.

Maxilliped (Figs 25-27, 39) well developed, strongly modified. Syncoxa with 2 pinnate setae. Basis with unequal denticulate projections and distal half of border curved and with irregular margin. Endopod 1-segmented; with strong serrate claw implanted near curved projection, and 1 small seta.

P1 (Figs 28, 43) similar to female. Coxa and basis fused, with rows of stout spinules along proximal margin, row of long spinules near inner distal corner, long naked seta on outer edge and 2 pinnate setae on inner distal corner. Exp-1 and Exp-2 with 1 outer seta each, and row of spinules along outer margin. Exp-3 with row of denticles along outer margin, 3 outer setae (2 pinnate and 1 naked), 1 apical bipinnate seta and 2 inner bipinnate setae. Enp-1 with adhesive fringe along distal margin, stout curved process with adhesive fringe (Fig. 46) and long pinnate seta on inner distal corner. Enp-2 and Enp-3 as in female.

P2-P4 (Figs 29-30) lacking outer spine on Exp-3. P4 (Fig. 30) without inner seta on Exp-3. Armature formula of P2-P4 as follows (Roman numerals representing spines, Arabic numerals representing setae):

P 5 (Fig. 31) smaller than in female.

P6 (Fig. 31) represented by membranous flaps with bipinnate seta.

Variability.

One female paratype showed left P3 endopod modified - enp-2 with only 1 seta and enp-3 with 8 elements in total (I,II, I+4).

Etymology.

The new species is named in honor of Prof. Dr. Sérgio de A. Rodrigues (Universidade de São Paulo) in recognition of his significant contributions to the taxonomy of Callianassidae and who kindly made available the studied material.