Carraroenia ruthae gen. et sp. nov. (Copepoda, Harpacticoida, Laophontidae) from maerl substrates of the Irish west coast Author Edward text Zootaxa 2006 1202 39 52 journal article 50808 10.5281/zenodo.172326 5eaf9969-2299-4936-9547-a70a4dbcf734 1175­5326 172326 Carraroenia ruthae gen. et sp. nov. ( Figures 1–6 ) Material examined Two females and one male from Coral Strand, An Dóilín, Carraroe, County Galway, Ireland ( 53°15’ N , 9°38’ W ), collected by E. McCormack, 22 May 2001 . Holotype : adult female ( BNHM 2004.69), completely dissected and mounted on 4 slides. Paratypes : adult female ( BNHM 2004.70) and adult male ( BNHM 2004.71) dissected and mounted on 4 and 5 slides respectively. All specimens deposited in the British Natural History Museum, London. Etymology The genus name alludes to the type locality at Carraroe, County Galway. The type species is named after the author’s little sister Ruth. FIGURE 1. Carraroenia ruthae gen. et sp. nov. , female (holotype): A, habitus, dorsal; B, habitus, lateral; C, caudal setae IV and V. Description of female Body length measured from anterior margin of cephalothorax to posterior margin of caudal rami 410 µm. Maximum width measured midway along cephalothorax, 94 µm. Body ( Figs 1 A–C) cylindrical, not dorsoventrally depressed, tapering slightly posteriorly. Cephalothorax marginally wider than free somites, with symmetrical distribution of sensillae. Posterolateral corners of cephalothorax produced into lobate extensions. Posterior margin of cephalothorax and pedigerous somites with rows of long sensillae interspersed with small setules. Urosome 5­segmented, comprising P5­bearing somite, genital double­somite and 3 free abdominal somites. Posterior ventral margins of urosomites, penultimate and anal somites excepted, with large spinules. Genital double­somite with transverse surface ridge with row of setules and pairs of sensillae dorsally and laterally indicating original segmentation; completely fused ventrally. Genital field ( Fig. 2 F) with copulatory pore located medially, with cone­shaped extension. Gonopores covered by opercula derived from sixth legs. P6 bearing small, naked seta. Anal somite ( Fig. 2 G) with well developed operculum­bearing row of fine spinules and flanked by pair of sensillae. Caudal rami ( Fig. 2 G) cylindrical, length more than 5 times width; each ramus with 7 setae: seta I naked, shortest; seta II and III naked; seta IV and V ( Fig. 1 C) well developed, bipinnate with fracture planes (seta V longest; longer than urosome); seta VI naked; seta VII located dorsally, naked and triarticulate at base. Each ramus with row of spinules on distal ventral surface. FIGURE 2. Carraroenia ruthae gen. et sp. nov. , female (holotype): A, antennule; B, antenna; C, mandible; D, maxillule; E, maxilla; F, genital field; G, caudal rami. FIGURE 3. Carraroenia ruthae gen. et sp. nov. , female (holotype): A, P1; B, P3; C, P4; D, P5. Rostrum ( Fig. 1 A) bell­shaped, delimited at base by transverse suture; with pair of sensillae and tube pore apically. Antennule ( Fig. 2 A) 6­segmented. Segment 1 with spinular rows on anterior and posterior margins and anterior distal corner. Segments 2 and 3 equal length with rows of spinules on posterior margin. Segment 4 with pedestal bearing aesthetasc fused basally to naked seta. Armature formula: 1­[1], 2­[7 + 1 pinnate], 3­[6], 4­[1 + (1 + ae)], 5­[1], 6­[9 + trithek]. Apical trithek consisting of small aesthetasc fused to 2 naked setae. Antenna ( Fig. 2 B) 3­segmented, comprising coxa, allobasis and free 1­segmented endopod. Coxa with rows of spinules on anterior and posterior margins. Allobasis robust with 1 pinnate abexopodal seta in distal half. Exopod slender with 4 elongate pinnate setae (2 laterally, 2 apically). Endopod of equal length with allobasis; lateral armature arising in distal half, consisting of 2 naked spines and 1 long, naked seta; apical armature consisting of 2 naked spines and 3 geniculate setae, outermost fused at base to small naked seta. Endopod with rows of spinules on anterior and posterior margins. Mandible ( Fig. 2 C) with robust gnathobase bearing 2 bicuspidate and several multicuspidate teeth around distal margin and long, pinnate seta at distal corner. Palp with exopod and endopod fused to basis, represented by 1 and 3 naked setae respectively; basal armature represented by naked seta. FIGURE 4. Carraroenia ruthae gen. et sp. nov. , male (paratype): A, habitus, lateral; B, habitus, dorsal; C, caudal setae IV and V. FIGURE 5. Carraroenia ruthae gen. et sp. nov. , male (paratype): A, antennule; B–G, antennulary segments 3–8; H, P5 and P6. Maxillule ( Fig. 2 D) small with praecoxal arthrite bearing row of spinules on anterior surface and 7 elements around distal margin. Coxa with cylindrical endite bearing naked spine and naked seta. Basal endite produced into strong pinnate claw with 2 naked accessory setae. Endopod incorporated into basis, represented by 3 naked setae. Exopod 1­ segmented with 1 long and 1 shorter, naked seta. Maxilla ( Fig. 2 E), syncoxa with row of spinules around outer margin; with 2 cylindrical endites. Praecoxal endite absent. Proximal endite with naked spine, 1 naked and 1 bipinnate seta; armature of distal endite same as for proximal endite. Allobasis strong with pinnate claw, slightly curved distally; accessory armature 2 naked setae. E ndopod small with 3 naked setae. Maxilliped ( Fig. 6 D) with 2 bipinnate setae at distal end of syncoxa and rows of spinules on outer margin and anterior surface. Basis length almost 3 times width, with row of spinules on outer margin. Endopod drawn out into long claw; accessory armature consisting of proximal naked seta. P1 ( Fig. 3 A), coxa large with row of spinules along outer margin. Basis with bipinnate spine on distal pedestal, bipinnate spine along outer margin and rows of spinules along outer and inner margins. Exopod 3­segmented; exp­1 with bipinnate spine; exp­2 with naked outer spine; exp­3 with 2 naked spines and 2 geniculate setae. Endopod 2­ segmented; enp­1 twice as long as exopod, with long spinular rows along inner margin; enp­2 with strong claw and small, naked seta. P2–P4 ( Figs 3 B–C, 6A). Coxae with spinular rows along outer margin. Bases with spinular rows along inner and outer margins; outer margin of basis with bipinnate spine (P2) or naked seta (P3–P4). Exopods 3­segmented, endopods 2­segmented. Outer margins of exopods, and outer and inner margins of endopods with rows of spinules as figured. Armature formula:

Exopod	Endopod (female) Endopod (male)
P2	0.1.0 23	0.010 0.010
P3	0.1.123	0.121 0.0.0 20
P4	0.1.123	0.220 0.111

P5 ( Fig. 3 D) with separate exopod and baseoendopod, each with sparse spinular ornamentation as figured. Baseoendopod forming long outer setophore bearing basal, naked seta (lost during dissection). Endopodal lobe with 2 apical setae (1 naked, 1 bipinnate) and 3 lateral, bipinnate setae. Exopod elongate, length approximately 4 times width; bearing 6 setae (innermost bipinnate); apical seta considerably longer than others and set on a tubular extension; 2 proximal setae superimposed. Description of male Body ( Figs 4 A–C) length measured from anterior margin of rostrum to posterior margin of caudal rami 404 µm. Maximum width measured at posterior margin of cephalothorax 87 µm. Sexual dimorphism in antennule, P3, P4, P5, P6 and genital segmentation. Thoracic somites as in female. Urosome 6­segmented, comprising P5­ bearing somite, genital somite and 4 free abdominal somites. Antennule ( Figs 5 A–G) 8­segmented; subchirocer with geniculation between segments 5 and 6. Segment 1 with rows of spinules along anterior margin and anterior distal corner. Segment 4 ( Fig. 5 C) represented by small sclerite along anterior margin. Segment 5 swollen. Armature formula: 1­[1], 2­[8 + 1 pinnate], 3­[7], 4­[2], 5­[9 + 1 pinnate + 1 modified + (1 + ae)], 6­[1 + 3 spinous processes], 7­[1], 8­[8 + trithek]. Apical trithek consisting of small aesthetasc and 2 naked setae. P2–P4 ( Figs 6 B–C) exopods 3­segmented, endopods 2­segmented in P2 and P4 and 3­ segmented in P3. P2 as in female ( Fig. 6 A). P3 ( Fig. 6 B) enp­1 without seta; enp­2 produced into bifurcate apophysis; enp­3 with short, naked inner seta and long, bipinnate outer seta located apically. P4 ( Fig. 6 C) exp­1 and exp­2 with modified spines. Enp­1 without seta; enp­2 with 3 apical, bipinnate setae. P5 ( Fig. 5 H) fused medially; defined at base. Baseoendopod with setophore bearing long, naked seta, and rudimentary endopodal lobe bearing 2 naked setae and inner tube pore; few spinular rows along surface. Exopod length approximately 3 times width; with 5 naked setae (2 outer, 1 apical and 2 inner); sparse spinular ornamentation on anterior surface as figured. P6 ( Fig. 5 H) asymmetrical; represented on both sides by small plate (fused to ventral wall of supporting somite along one side; articulating at base and covering gonopore along other side); outer distal corner produced into cylindrical process bearing bipinnate inner spine and outer naked seta.