Harris: The copepod genus Porcellidium 
75 
Porcellidium viride (Philippi, 1840) 
Figs 4-8 
Thyone viridis Philippi, 1840:190, pi. IV, fig 2. 
Porcellidium subrotundum Norman, 1868.—Brady, 1880: 
169-170. 
Porcellidium lecanoides Claus, 1889.—Holmes & O’Connor, 
1990: 66; Huys et al., 1996: 308; Walker-Smith, 2001: 
656; Wells, 2007:79. 
Porcellidium viride. —Brady, 1880: 168-169; Lang, 1948: 
420^122; Apostanov & Marinov, 1988: 101-102; Harris 
& Robertson, 1994: 301; Bodin, 1997: 65. 
Porcellidiumfimbriatum Claus, 1889.—Brady, 1880 (female): 
167; Thompson & Scott, 1903: 227; Sars, 1904: 76-77. 
P. fimbriatum var. heraldicum. —Monard, 1928: 324-326; 
Monard, 1935. 
Porcellidium sarsi. —Bocquet, 1948: 237-259; Holmes 
& O’Connor, 1990: 66-67; Harris & Robertson, 1994: 
301; Huys et al. , 1996: 308; Walker-Smith, 2001: 656; 
Wells, 2007: 79. 
Thyone viridis Philippi.—Vervoort, 1964: 119. 
Type material. Due to the apparent absence of a type 
specimen for Philippi’s Thyone viridis , a male specimen, 
(identified as Porcellidium viride from Brady’s illustration of 
the antennule) is here designated neotype to give taxonomic 
stability to the genus Porcellidium and to allow sufficient 
definition of the specific characteristics to ensure recognition 
of Porcellidium viride. 
Neotype designation. Neotype adult male with antennules 
extended, length 0.63 mm, P90778 deposited at the Australian 
Museum, Sydney; collected from Laminaria digitata, Clachan, 
Seil Sound, Oban, Scotland (56° 19'N 5°35'W), V A. Harris 1997. 
Material examined (specimens here determined to be 
conspecific with the neotype): an adult female with egg mass 
detached, length 0.92 mm (AM P90779) and other specimens 
(20 $ $, 8 and coupled S +juv. $, AM P89054), deposited 
at AM, Sydney. Specimens from the same locality and species 
of seaweed (100 $ $, 50 SS and 6 SS + juv. and 4 slide 
mounted specimens) have been deposited at NHM, London. 
Slide material in NHM, London {Porcellidium 339) and NMI, 
Dublin (see Appendix 1 and 2). Living material, identified as 
Porcellidium viride from a species specific feature of the male 
antennule shown in Brady’s (1880) illustration, was collected 
from Castle Head, Dale, Pembrokeshire (51°42'N 5°10'W), 
Clachan, Seil Sound, Oban, Scotland (56°19'N 5°35'W) and 
Loch Hyne, Co. Cork, Ireland (51°30'N 9°17'W) and is part 
of the material examined. The following description is based 
on the neotype and this material examined. 
Diagnosis. Male antennule segment 2 with first (proximal) 
seta more than twice length of second or third seta, five 
setae on segment 2 finely plumulose, segment 3 with ventral 
process or “peg”, three coupling denticles on segment 4 are 
conspicuous denticulate pads, dactylus (segment 5) expanded, 
hooked distally, segment 6 inconspicuous; ventral surface 
of male rostrum smooth, no U-shaped wrinkles or ridges, 
ventral surface of female rostrum V-shape (Fig, 6F); female 
caudal ramus rectangular, 1/w = 2, tenninal setae T2 and T3 
thin, plain, very close together, posterior border between 
setae T3 and T4 > ’A width of ramus, Hicks’ index for (3 seta 
45-50%; boundary between anterior and posterior lobes of 
female genital double-somite marked by a clear triangular area 
without border setules or dorsal pits, border of posterior lobe 
with three sens ilia at edge; male P5 exopod almost rectangular, 
posterior angle 80°; females carry 24 eggs. Spermatophore 
elongate, ephemeral on female. 
Biometric data. Females (N = 50): maximum length (L m ax) 
0.91 mm, body length to end of genital double-somite (L U rs) 
0.89 mm, range 0.83-0.95 mm; cephalosome width (W) 
0.60 mm, range 0.56-0.62 mm; rostrum width (R) 0.15 mm; 
genital double-somite width (N = 5) 0.38 mm, length 0.26 
mm; caudal ramus length (N = 15) 0.14 mm [ramus dissected, 
laid flat], width 0.06 mm. 
Ratios: L urs AV 1.48; W/R4.0; genital double-somite 63% 
of cephalosome width, w/11.45; caudal ramus 16% of L U rs, 
1/w 2.3, Hicks’ index for |3 seta 50%. 
Males (N = 16): maximum length 0.62 mm, body length to 
end of genital segment 0.49 mm; cephalosome width 0.52 
mm; antennule (N = 7, fully extended) 0.15 mm; apical angle 
of P5 75-80°; spermatophore length 0.21 mm. 
Ratios: male antennule 30% of cephalosome width; 
antennule segment 2,33%, segment 3+4 37%, dactylus 24% 
of antennule length; first seta on segment 2 of antennule is 
2.5-2.8 times length of seta 2; spermatophore 43% of body 
length L urs . 
Description. Adult females (Fig. 4A; Plate IB, p. 67): pale 
yellow or colourless with variable patches of dark blue/purple 
on cephalosome and posterior of body (see Figs 4A, 8A, F, G, 
H, I and Remarks below). Cephalosome semicircular, rostrum 
broad (w/1 4.2), V-shape in ventral view (Fig. 6F). Hyaline 
border with eight border sensilla surrounds cephalosome, 10 
pm wide. Dorsal surface ornamented with circular pits 4—5 
pm, surface ridge near antennule socket (Fig. 8B, C), ventral 
surface of cephalosome smooth (not wrinkled). Labrum with 
oval patch of minute setules (Fig. 4F). Genital double-somite 
(Fig. 4C) broad, semicircular in outline, no cleft or notch but 
clear triangular area without border setules or dorsal pits marks 
boundary between anterior and posterior lobes, three very 
small sensilla at edge of posterior lobe (Fig. 4D). Posterior 
arch deep (14 length of genital double-somite), encloses almost 
whole of caudal rami. Genital opening (Fig. 4E). Caudal rami 
(Fig. 4B) long, rectangular, feint ridges on dorsal surface, 
(3 seta half way down ramus, y seta and pinnate T1 slightly 
recessed at lateral comer, T2 and T3 plain, slender, very close 
together (T2 pinnate on some specimens), space between T3 
and T4 greater than half width of ramus, T4 pinnate at medial 
comer (Fig. 4G). Some of the setae on segment 2 of female 
antennule finely plumulose (Fig. 5A). Structure and setation of 
mouthparts and ambulatory limbs typical of family. Antenna 
(Fig. 5B), endopod segment 2 with two lateral setae, ends of 
geniculate setae plain, claw comb-like (Fig. 5C). No patch of 
setules on anterior lobe of mandibular palp (Fig. 5E). Maxillule 
(Fig. 5G) with single bulbous seta on exopod, six setae on 
endopod. Coxae of maxilliped meet in midline (Fig. 5H). 
Limb PI, endopod segment 1 triangular, broad (1/w = 0.95), 
peg area inconspicuous (Fig. 5F). Serrulate spinous seta on 
segment 2 of P3 endopod (Fig. 6G) almost as long as endopod 
(0.9:1), large serrate spinous terminal seta on segment 3 longer 
than endopod (1.4:1). Spinous setae on P4 endopod segment 
2 and 3 (Fig. 6C) longer than endopod (1.3:1). P5 exopod 
lanceolate with two plain dorsal setae (one sub-terminal and 
one apical), minute third seta present on some specimens (Fig. 
6H). Females cany 24 eggs per brood. 
Adult males (Fig. 8A; Plate ID, p. 67). Dark blue/purple 
area only on cephalosome, posterior of body colourless. 
Cephalosome truncated, anterior border straight, shoulder 
