Carraroenia ruthae

Edward, 2006, Carraroenia ruthae gen. et sp. nov. (Copepoda, Harpacticoida, Laophontidae) from maerl substrates of the Irish west coast, Zootaxa 1202, pp. 39-52 : 41-48

publication ID	https://doi.org/ 10.5281/zenodo.172326
DOI	https://doi.org/10.5281/zenodo.6255815
persistent identifier	https://treatment.plazi.org/id/03E22A31-ED7D-C336-410A-1F57E526FD2C
treatment provided by	Plazi
scientific name	Carraroenia ruthae
status

Treatment

Carraroenia ruthae gen. et sp. nov.

( Figures 1–6 View FIGURE 1 View FIGURE 2 View FIGURE 3 View FIGURE 4 View FIGURE 5 View FIGURE 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.

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 View FIGURE 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 View FIGURE 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 View FIGURE 2 G) with well developed operculumbearing row of fine spinules and flanked by pair of sensillae.

Caudal rami ( Fig. 2 View FIGURE 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 View FIGURE 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.

Rostrum ( Fig. 1 View FIGURE 1 A) bellshaped, delimited at base by transverse suture; with pair of sensillae and tube pore apically.

Antennule ( Fig. 2 View FIGURE 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 View FIGURE 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 View FIGURE 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.

Maxillule ( Fig. 2 View FIGURE 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 View FIGURE 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 View FIGURE 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 View FIGURE 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 View FIGURE 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:

P5 ( Fig. 3 View FIGURE 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 View FIGURE 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 View FIGURE 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 View FIGURE 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 View FIGURE 6 B–C) exopods 3segmented, endopods 2segmented in P2 and P4 and 3 segmented in P3. P2 as in female ( Fig. 6 View FIGURE 6 A). P3 ( Fig. 6 View FIGURE 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 View FIGURE 6 C) exp1 and exp2 with modified spines. Enp1 without seta; enp2 with 3 apical, bipinnate setae.

P5 ( Fig. 5 View FIGURE 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 View FIGURE 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.