Porcellidiidae of Australia (Harpacticoida, Copepoda). II. The Importance of the Male Antennule in Taxonomy Author Harris, Vernon A. text Records of the Australian Museum 2014 2014-04-02 66 2 111 166 http://dx.doi.org/10.3853/j.2201-4349.66.2014.1595 journal article 10.3853/j.2201-4349.66.2014.1595 2201-4349 4684479 Ravania wellsi sp. nov. Figs 1–4 , Plate 1A Type material . HOLOTYPE adult male, length 0.51 mm , P81198 ; ALLOTYPE adult female, length 0.58 mm , P81199 ; PARATYPE specimens, 5 ♀♀ , 3 ♂♂ , 3 juveniles , P81200, deposited at AM , Sydney. Additional paratypes deposited at NHM, London. All collected from Eucheuma denticulatum , sublittoral fringe, Point Vernon , Hervey Bay , Queensland (25°15' S 152°47' E), V . A. Harris , 1998 . Diagnosis . Male antennule with short pointed spur or thorn-like denticle at base of δ seta on segment 3; anterior half of female genital double-somite without border setules, posterior half with border setules, no seta in lateral indentation between anterior and posterior lobes, half caudal ramus contained in arch of genital double-somite; female caudal ramus rhomboid, terminal seta T2 almost as long as γ seta; male P2 with only two terminal plumose setae on endopod segment 3; female P4 with two spinous setae on endopod; female P5 exopod with one dorsal and two apical setae; male P5 with short rows of ventral setules at base of each terminal seta. Biometric data . Females (N = 29): maximum length ( Lmax ) mean 0.57 mm , range 0.54–0.61 mm , body length ( Lurs ) mean 0.52 mm , range 0.49–0.56 mm ; cephalosome width (W) mean 0.36 mm , range 0.34–0.44 mm ; rostrum width 0.08 mm ; width of genital double-somite 0.23 mm , length 0.14 mm , arch 0.08 mm ; caudal ramus 0.115 mm , width 0.042 mm . Ratios: Lurs / W 1.44 , W/R 4.5; genital double-somite w/l 1.65, arch 57% of length; caudal ramus 22% of Lurs , ramus l/ w 2.7 , Hicks’ index for β 68%. Males (N = 23): length ( Lmax ) mean 0.51 mm , range 0.49–0.54 mm , body length ( Lurs ) mean 0.48 mm , range 0.46–0.51 mm ; cephalosome width 0.35 mm . antennule (N = 3, fully extended 0.125 mm ; spermatophore 0.18 × 0.065 mm . Ratios: Lurs / W 1.4 ; antennule 24.5% of Lurs , antennule segment 2 31%, segment 3+4 35%, dactylus 21% of antennule length; spermatophore 37% of body length Lurs .. Description . Adult females ( Fig. 1A ; Plate 1A, p. 163): colouration, pale red with central cephalosome and metasome segments 1 and 2 deep red, metasome segments 3 and 4 pale red, genital double-somite and caudal rami deep red. Some animals are pale red or colourless. Eye spot dark brown. Anterior of cephalosome broadly rounded, rostrum prominent, narrow with hyaline anterior border. Dorsal surface ornamented with pits ( 4 µm ). Hyaline border 8 µm wide, without striations. Sensillum on epipleural lobe of second metasome segment conspicuous, longer than other species. Labrum without central patch of setules or ridge plates. Genital double-somite ( Fig. 1E ) with slight indentation that marks the boundary between anterior and posterior lobes, anterior lobe short, convex, with thickened edge but no setules, posterior lobe triangular, pointed posteriorly with border setules.Arch of genital double-somite deep, encloses about half length of caudal ramus, dorsal surface with pits. Genital opening as in Fig. 1F . Caudal rami ( Fig. 1D ) rhomboid, length about 21/2 times width, sides almost parallel, oblique posterior edge slightly convex, apex broadly rounded with pinnate T4. Dorsal surface with prominent network of ridges, β seta 1/3 way down ramus, γ seta about 1/2 way along oblique edge. Medial edge with border setules up to the level of β seta, lateral edge slightly convex with border setules distally, T1 unipinnate at lateral corner of oblique edge, T2 plain about as long as γ seta, T3 absent, posterior border with fine setules from T1 to T4. Structure and setation of mouthparts and ambulatory limbs typical of family. Antenna ( Fig. 2A ) exopod with five plumulose setae and one finely serrulate spinous seta, endopod segment 2 with two lateral setae, geniculate setae with plain end segment, claw fine comb-like. Mandible ( Fig. 2D, E, F ) without setules on anterior lobe of palp. Maxillule ( Fig. 2B ), endopod with six setae, exopod with one bulbous seta. Maxilla ( Fig. 2H ) and maxilliped ( Fig. 2G ) typical. No area of denticulate setules on P1endopod ( Fig. 2C ). Serrulate spinous seta on segment 3 of P2 endopod about 1/2 length of endopod (Fig. 3C). Serrulate spinous seta on segment 2 of P3 endopod (Fig. 3A) shorter than endopod (0.8:1), large serrate spinous seta on segment 3 longer than endopod (1.3:1). Internal seta on segment 2 and segment 3 of P4 endopod strong spinous, other setae plumose (Fig. 3F). Dorsal surface of P5 exopod with pits, internal seta on baseoendopod serrulate, about 1/2 length of exopod, exopod lanceolate with one dorsal seta and two apical setae (Fig. 3E). P5s reach beyond genital double-somite to extremity of caudal rami, but do not touch posteriorly. Females carry six large eggs. Adult males ( Fig. 1B ; Plate 1B, p. 163). Colouration similar to female, but posterior region of most specimens is pale red or colourless. Anterior of cephalosome rounded (not truncated), rostrum projects anteriorly, in ventral view rostrum appears Figure 1. Ravania wellsi sp. nov. Female: (A) adult; (D) caudal ramus (left ventral, right dorsal); (E) genital double-somite and caudal rami; (F) genital opening. Male: (B) adult; (C) caudal ramus. Scale bar: A, B = 0.37 mm. C, D = 0.08 mm. E = 0.15 mm. F = 0.06 mm. Figure 2. Ravania wellsi sp. nov. Female: (A) antenna; (B) maxillule; (C) P1; (D) mandible; (E, F) left and right molar process; (G) maxilliped; (H) maxilla. Male: (I) antennule (ventral). Scale bar: A, I = 0.08 mm. B = 0.06 mm. C, D = 0.14 mm. E, F, H = 0.1 mm. G = 0.12 mm. Figure 3. Ravania wellsi sp. nov. Female: A, P3. C, P2. E, P5 (dorsal). F, P4. Male: B, P2 endopod. D, P5 (ventral). Scale bar: A, D, E = 0.1 mm . B, C = 0.14 mm . F = 0.08 mm . oval with keeled anterior half ( Figs 4B, C ). Dorsal pits and hyaline border as for female. Caudal rami quadrate, slightly longer than wide ( Fig. 1C ). Dorsal surface with network of ridges, medial edge straight with border setules distally, lateral edge convex with border setules distally. Terminal seta T1 unipinnate, recessed, T2 plain, almost as long as γ seta, T3 absent, T4 plain, set in from medial corner. Posterior border straight, fringed with fine setules. Antennule ( Figs 2I , 4D ) characteristic of genus. Seta on segment 1 plumose, segment 3 with short, pointed spine-like denticle close to anterior lobe, δ seta very long (1/2 length of antennule), projects anteriorly ( Fig. 2I ), two tooth-like coupling denticles on segment 4, aesthetasc extremely long (almost as long as fully extended antennule ( Fig. 2I ), dactylus long, cylindrical. Endopod of P2 with two plumose terminal setae (Fig. 3B). No spinous setae on P4 endopod, all setae plumose. Dorsal surface of P5 exopod with pits, ventral setules at base of each terminal seta (Fig. 3D). Etymology . The species has been named in recognition of Dr J. B. J. Wells’ contribution to the taxonomy of the Harpacticoida . Distribution . Type series collected from Eucheuma denticulatum, Point Vernon, Hervey Bay, PV 4. 7/98, 41 ♀♀ (21 with eggs), 26 ♂♂ , 14 juveniles . Also found on Zonaria sp., PV8, 8/00, 12 ♀♀ , 14 ♂♂ at the same location. The species has been recorded at Arrawarra headland, northern NSW, on Caulerpa vesiculosus and Dilophus sp. V.A. Harris, 1982, 2000.