Kushia spathoides, Harris, 2014

Harris, Vernon A., 2014, Porcellidiidae of Australia (Harpacticoida, Copepoda). II. The Importance of the Male Antennule in Taxonomy, Records of the Australian Museum 66 (2), pp. 111-166 : 133-138

publication ID	https://doi.org/ 10.3853/j.2201-4349.66.2014.1595
persistent identifier	https://treatment.plazi.org/id/03E56619-FFC4-3201-F742-78F4529A48F2
treatment provided by	Carolina
scientific name	Kushia spathoides
status	sp. nov.

Treatment

Kushia spathoides sp. nov.

Figs 15–18 View Figure 15 View Figure 16 View Figure 17 View Figure 18 , Plate 1I

Type material. HOLOTYPE adult male, length 0.68 mm, P81204 ; ALLOTYPE adult female, length 0.75 mm, P81205 ; PARATYPE specimens, 5 ♀♀, 5 ♂♂, P81206, deposited at AM, Sydney. Additional paratypes deposited at NHM, London. All collected at Arrawarra Headland , Woolgoolga, northern NSW, Australia (30°06' S 153°02' E), washed from Caulerpa vesiculifera in coral rockpool, V. A. Harris, 1982 .

Diagnosis. Striations in hyaline border close to edge of cephalosome ( Fig. 15E View Figure 15 ); male cephalosome rounded anteriorly (very slight truncation), shoulders smoothly rounded; anterior comb on male antennule short (length about twice width), small finger-like ventral process lies between anterior comb and π setae on segment 3 of male antennule ( Fig. 18F View Figure 18 ), proximal coupling denticle on segment 4 flat with serrate edge, middle denticle Y-shaped with plain edge, dactylus not bent or hooked distally; female caudal ramus widens posteriorly, T1 recessed at lateral corner to give ramus pentagonal appearance; dorsal seta 1 on female P5 exopod very small, seta 2 large ( Fig. 16D View Figure 16 ).

Biometric data. Females (N = 10): maximum length (Lmax) mean 0.75 mm, range 0.72–0.76 mm, body length (Lurs) mean 0.71 mm, range 0.69–0.72 mm; cephalosome width (W) mean 0.48 mm, range 0.45–0.51 mm; rostrum (R) 0.095 mm; genital double-somite width 0.27 mm, length 0.20 mm; caudal ramus width (mean) 0.055 mm, length 0.11 mm.

Ratios: Lurs / W 1.46, Lmax / W 1.54; cephalosome W/R 5.1; genital double-somite w/l 0.73, arch 40% of length; caudal ramus 15% of Lurs, l/ w 2.0, Hicks’ index for α 73%, for β 55%. Males (N = 7): maximum length (Lmax) mean 0.68 mm, range 0.66–0.70 mm, body length (Lurs) mean 0.63 mm, range 0.62–0.67 mm; cephalosome width (W) mean 0.46 mm, range 0.43–0.47 mm, length 0.35 mm; caudal ramus width 0.05 mm, length 0.05 mm; antennule (fully extended) 0.19 mm, length of anterior comb on antennule 0.02 mm; spermatophore 0.23 × 0.07 mm.

Ratios: Lurs / W 1.38, Lmax / W 1.47, cephalosome 52% of Lmax; caudal ramus l/ w 1.0; antennule 28% of body length; segment 3+4 40%, dactylus 33% of antennule length; spermatophore 34% of Lmax.

Description. Adult females ( Fig. 15A View Figure 15 ; Plate 1I, p. 163): colour pink. Body outline elliptical, rostrum prominent, narrow. Dorsal pits conspicuous (4–6 µm), hyaline border (8 µm wide) appears striated due to edge of overlapping pits that project about 4 µm over hyaline border ( Fig. 15E View Figure 15 , 18D View Figure 18 ). Twelve or more conspicuous marginal glands on each side of the cephalosome with ducts that open just above hyaline border ( Figs 15A,E View Figure 15 , 18A,D View Figure 18 ). Similar glands are found in the epipleura of metasome segments, genital double-somite, caudal rami and P5 limbs. Dorsal surface of genital doublesomite with pits, lateral border smoothly curved without notch or scar to indicate boundary between anterior and posterior lobes, border setules absent except for a few short setules at pointed posterior extremity, arch less than half length of genital double-somite ( Fig. 15B View Figure 15 ). Genital opening as shown in Fig. 15F View Figure 15 . Labrum without ridge plates. Caudal rami ( Fig. 15D View Figure 15 ) widen posteriorly (maximum width about 4/5 down ramus), dorsal surface with faint reticulation. Beta seta almost half way down ramus, γ seta slightly recessed on posterior border, T1 recessed at lateral corner, T2 and T3 setae extremely close, T4 short at medial corner, posterior border thickened with three dorsal ridges ( Fig. 15C View Figure 15 ), fine setules along posterior border. Structure and setation of mouthparts and ambulatory limbs typical of family. Antenna ( Fig. 16A View Figure 16 ) basis with diagonal row of triangular setules, marginal setules on segments 1 and 2 of endopod, exopod with five finely plumulose setae and one spinous seta, three lateral setae on segment 2 of endopod, geniculate setae with plain terminal section, small sensory structure present, claw comb-like. Mandible ( Fig. 16B View Figure 16 ) with small group of setules on anterior lobe of palp. Maxillule ( Fig. 16G View Figure 16 ) with single seta on exopod. Maxilla and maxilliped as in ( Fig. 16F, C View Figure 16 ). P1 endopod segment 1 narrow (l/w = 1.28), ( Fig. 16H View Figure 16 ) with small triangle of denticulate setules at lateral corner of fimbriate crescent. Serrulate spinous seta on segment 3 of P2 endopod 3/4 length of endopod ( Fig. 17A View Figure 17 ). Serrulate spinous seta on segment 2 of P3 endopod ( Fig. 17B View Figure 17 ) equal in length to endopod (1:1), large serrate spinous seta on segment 3 longer than endopod (1.35:1). Endopod of P4 with a plain spinous seta on segment 2 and similar first internal seta on segment 3 ( Fig. 17D View Figure 17 ). Baseoendopod of P5 with triangular prominence on posterior border ( Fig. 16D View Figure 16 ), exopod lanceolate, dorsal surface with pits, ventral expansion below falciform ridge ( Fig. 16E View Figure 16 ) lies under edge of genital double-somite, first dorsal seta very small or absent, second seta long, apex with two setae. Females carry 12 eggs.

Adult males ( Fig. 18A View Figure 18 ). Colour pink. Anterior of cephalosome rounded, only slightly truncated, shoulders smoothly rounded, lateral angle of antennule socket prominent. Hyaline border, marginal glands and border striations as for female ( Fig. 18D View Figure 18 ). Caudal rami ( Fig. 18C View Figure 18 ) widen posteriorly (maximum width almost twice proximal width), lateral and posterior border convex, length equal to maximum width, dorsal surface with faint reticulate pattern. Setation similar to female, but posterior border without three dorsal ridges. Antennule ( Fig. 18F View Figure 18 ), anterior comb on segment 3 broad (spatulate), small finger-like ventral process present between anterior comb and π setae. First coupling denticle flat with double row of serrations along edge, second denticle longer, widens distally, without serrated edge, third denticle circular without serrated edge ( Fig. 18E View Figure 18 ). Dactylus straight, 3/4 length of segment 3+4, no terminal hook. Aesthetasc very long (about 3/4 length of antennule). Limbs as described for female except for the following differences. P2 with two plumose terminal setae on segment 3 of endopod ( Fig. 17F View Figure 17 ). Terminal spinous seta on P3 endopod equal in length to endopod. P4 endopod setae not spinous ( Fig. 17E View Figure 17 ). P5 trapezoid ( Fig. 17C View Figure 17 ), dorsal surface with pits, about 15 fine ventral setules at base of first (lateral) seta, diagonal row of five or six setules at base of each terminal seta. Spermatophore large (1/3 body length). Cells secreting spermatophore capsule shown in Fig. 18B View Figure 18 .

Etymology. The trivial name, spathoides , refers to the broad spatulate anterior comb on segment 3 of the male antennule (G. spathe = ladle or spatula + oides = shape). It contrasts with the long narrow comb on Japanese species.

Remarks. The genus Kushia is known from Japan, but K. spathoides is the first record for Australia.

Distribution. This species was collected from Caulerpa vesiculifera growing in a coral rock pool at Arrawarra Head, NSW, but was not found at Nambucca Heads (60 km south) or Ballina (140 km north). All females in type series, (Aw14,11/82, 42 ♀♀, 41 ♂♂, 26 juveniles) carry eggs, nine of the males were coupled to juvenile females, V. A. Harris 1982.