Notomasticola frondosus, Kim & Sikorski & O’Reilly & Boxshall, 2013

Kim, Il-Hoi, Sikorski, Andrey, O’Reilly, Myles & Boxshall, Geoff A., 2013, Copepods associated with polychaete worms in European seas, Zootaxa 3651 (1), pp. 1-62 : 57-60

Notomasticola frondosus n. sp.

Type material: Holotype ♀ (intact specimen) from Notomastus latericeus ; Gullifaks Stn 1-3 (61.094ºN, 02.193ºE), depth 133 m, 17 June 1999; BMNH Reg. No. 2012.1421.

Paratype ♀ (dissected on glass slides and figured) from Pseudopolydora paucibranchiata ; Huldra 99, Stn 16-9 (61.933ºN, 02.555ºE), depth 125 m, 05 June 1999; BMNH Reg. No. 2012.1422 .

Paratype ♀ found in abdomen of N. latericeus ; Fal Estuary , Cornwall (Stn H 5), ( GRF 182 E336N), collected by P. Garwood, 05 February 1997; BMNH Reg. No. 2013.14 .

Paratype ♀ (dissected on glass slide) from the gut of N. latericeus fragment; Irish Sandbanks Survey Stn 551, depth unknown, collected by P. Garwood; BMNH Reg. No. 2013.15 .

Other material: 1♀ northern North Sea , Conoco Lyell Field, Stn 1 (60 o 53.944’N, 01 o 16.287'E), depth 140 m, collected by Sue Hamilton, July 1991; BMNH Reg. No. 2013.16 .

1♀ northern North Sea , Total Dunbar Field, Stn 9B (60 o 37.873’N, 01 o 39.155’E), depth 130 m, collected by Sue Hamilton, 30 May 1992; BMNH Reg. No. 2013.17 .

1♀ northern North Sea , Total Dunbar Field, Stn 6B (60 o 37.334’N, 01 o 39.177’E) collected by Sue Hamilton, 30 May 1992; BMNH Reg. No. 2013.18 .

4♀ northern North Sea from Statfjord Field (Blocks 33/34); collected by Sue Hamilton, 1996; BMNH Reg. No. 2013.19-22 .

1♀ from inside N. latericeus , northern North Sea , NW Hutton Field, Stn BP 800ESE(B), collected by P. Garwood, Summer 2002; BMNH Reg. No. 2013.23 .

1♀ off Rame Head , Cornwall, England, collected David Hall, 01 May 2007; BMNH Reg. No. 2013.24 .

2♀ northern North Sea, NW Hutton Field, Stn BP 1200ESE(B), collected by P. Garwood, Summer 2002.

1♀ Firth of Clyde , Scotland, Stn G 03-1 (55 o 44.922’N, 04 o 53.110’W), collected by David Hall, 26 June 2009 .

Female. Body ( Fig. 32A ) grub-shaped, elongate, consisting of obscurely defined cephalosome, long trunk, indistinct genital complex and 1-segmented abdomen. Body length 3.07 mm. Maximum width 740 µm. Trunk occupying most of body, with many transverse wrinkles and constrictions at irregular intervals. Genital complex much wider than long, 395 µm wide, bearing paired genital apertures dorsolaterally ( Fig. 32B ). Abdomen 1- segmented, 305×245 µm, slightly tapering. Caudal ramus ( Fig. 32C ) 58×28 µm (ratio 2.07:1), broadened distally, with 6 setae; one distal seta markedly larger than other 5.

Rostrum ( Fig. 32D ) as broad lobe on frontal margin of cephalosome. Antennule ( Fig. 32E ) broad and 4- segmented; terminal segment narrower than proximal 3 segments; armature formula 1, 3, 7, and 8; 3 of setae on terminal segment enlarged, flattened and spinulose. Antenna ( Fig. 32F ) incompletely 4-segmented, armature formula 1, 0, 1, 1+2 claws; articulation between 2 distal segments obscure.

Labrum ( Fig. 32G ) with slightly convex posterior margin and large tapering posteromedian process. Mandible ( Fig. 32H ) armed distally with 1 ventral lash and 2 dorsal, spinulose spines. Maxillule ( Fig. 32I ) bilobed, with 3 distal setae on small outer lobe and 2 proximal setae on large inner lobe. Maxilla ( Fig. 32J ) 2-segmented; proximal segment unarmed; distal segment forming claw, with 1 small proximal seta and 4 or 5 subdistal spinules near tip. Maxilliped absent.

Legs 1–3 ( Figs 32K , 33A, B ) biramous with 2-segmented rami; exopods small; endopods enlarged, with lamelliform segments. Leg 4 ( Fig. 33C ) represented by 1 seta. Outer spine of exopod of legs 1–3 forming claw, with bifurcate tip. Armature formula of legs 1–3 as follows:

Leg 1: coxa 0-0; basis 1-0; exp. I-0; 2, 3, 0; enp. 0-0; 0-0

Leg 2: coxa 0-0; basis 1-0; exp. I-0; 1, 2, 0; enp. 0-0; 0-0

Leg 3: coxa 0-0; basis 1-0; exp. I-0; 0, 3, 0; enp. 0-0; 0-0

Leg 5 large, located dorsolaterally, and 2-segmented ( Fig. 32B ); proximal segment expanded, globular and unarmed; free distal segment (exopod) also unarmed. Leg 6 represented by 1 seta in genital area ( Fig. 32B ).

Male. Unknown.

Etymology. The specific name frondosus is from the Latin meaning “leafy” and alludes to the leaf-like endopodal segments of legs 1–3.

Remarks. One of the observed paratypes (from the Irish Sandbanks Survey) was found in the gut of the polychaete host. It was about 3.7 mm in body length and had a smooth body surface, without wrinkles. However, the body of this female had two strong lateral constrictions, one at the level of leg 3 and the other anterior to leg 4 ( Fig. 33D ). The distance between the two constrictions corresponded exactly to the length of a body segment of the polychaete host, which suggests that the constrictions on the copepod body may have been caused by the muscular constrictions (at the host’s internal septa) of the gut of the host. Unlike the other specimens, this female also had maxillipeds ( Fig. 33E, F ) which were lobate with bulges. Despite the distinctly different body configuration and the possession of vestiges of maxillipeds, the morphological features of other appendages of this specimen, including the characteristic setation of the antennule, are the same as in the other observed specimens.

Four of the five specimens associated with hosts lived in the gut of Notomastus latericeus , a relatively large polychaete which we believe to be the typical host. We suspect that the other smaller polychaete, Pseudopolydora paucibranchiata , is not the usual host.

Figures

FIGURE 32. Notomasticola frondosus n. gen. et n. sp., holotype female. A, habitus, dorsal; B, urosome, dorsal; C, left caudal ramus, dorsal; D, rostrum; E, antennule; F, antenna; G, labrum; H, mandible; I, maxillule; J, maxilla; K, leg 1. Scale bars: A, 0.5 mm; B, 0.1 mm; C, D, K, 0.05 mm; E–J, 0.02 mm.

FIGURE 33. Notomasticola frondosus n. gen. et n. sp., holotype female. A, leg 2; B, leg 3; C, leg 4. Paratype female, D, habitus; E, F, maxillipeds. Scale bars: A, B, 0.05 mm; C, E, F, 0.02 mm; D, 0.5 mm.