Parabradya samsoni, Seifried, Sybille, Plum, Christoph & Schulz, Maximilian, 2007

Seifried, Sybille, Plum, Christoph & Schulz, Maximilian, 2007, A new species of Parabradya Lang, 1944 (Copepoda: Harpacticoida: Ectinosomatidae) from the abyssal plain of the Angola Basin *, Zootaxa 1432, pp. 1-21 : 4-14

Parabradya samsoni sp. nov.

Diagnosis (autapomorphies in italics):

Female. Whole body except cephalic shield and genital field covered with spinules. Many setae of A1, A2, mouthparts, P1–P5 and caudal rami multipinnate. Innermost seta of P5 not directly situated at inner distal, but displaced towards outer edge.

Type material: Holotype female, dissected and mounted on 22 slides, deposited in the Copepod Collection of the AG Zoosystematics and Morphology, University of Oldenburg, Germany ( UNIOL Coll. No. 2006.006/1-22), Atlantic Ocean, Angola Basin, 18°18.3’S 4°41.3’E, 5395 m. Paratype 1: dissected female ( UNIOL Coll. No. 2006.007/1-12), 16°18.1’S 5°27.2’E, 5390 m. Paratype 2: dissected female ( UNIOL Coll. No. 2006.008/1-6), 16°17.0’S 5°27.0’E, 5389 m. Paratype 3: undissected female ( UNIOL Coll. No. 2006.009/1), 16°18.1’S 5°27.2’E, 5390 m. Paratype 4: female prepared for SEM (2005, sample 8; UNIOL Coll. No. 2006.0017/1), 17°06.2’S 4°41.7’E, 5415 m. Paratype 5: female prepared for SEM (2005, sample 7; UNIOL Coll. No. 2006.0016/1), 16°18.1’S 5°27.2’E, 5390 m.

Additional material: 11 females from stations 318, 340, 344, and 348 (Tab. 1).

Type locality: Atlantic Ocean, Angola Basin, station 340 of DIVA-1 expedition, 18°18.3’S 4°41.3’E, 5395 m; salinity 34.8 psu; temperature 2.48 °C near the sea bottom; silt and clay sediment.

Description of the female holotype

All drawings made of holotype except paragnaths ( Fig. 4 D from paratype 1), one detail of mandible ( Fig. 5 B from paratype 2) and one detail of maxilla ( Fig. 7 B from paratype 2). SEM pictures are from paratypes 4 and 5.

Body length (incl. rostrum and without caudal rami): 1725 μm. Caudal rami: 110 µm. Maximum body width: 565 µm. Rostrum: 77 µm. Cephalothorax length (incl. rostrum): 690 µm.

Body ( Figs 1 A–C, 12–13) with distinction between prosome and urosome; prosome consisting of cephalothorax and 3 free pedigerous somites; first pedigerous somite completely fused to dorsal cephalic shield; urosome 5-segmented, comprising somite bearing P5, genital double-somite, and 3 free abdominal somites; 1 egg-sac, 1 copulatory pore. Cephalothorax longer than wide and wider than urosome. Cephalothorax and body somites with sensillae and pores ( Figs 1 A–C). Whole body except for cephalic shield and genital field covered with small spinules ( Figs 12–13 ). Hyaline frill of cephalothorax and last 2 abdominal somites plain ( Figs 13 B,D), that of cephalothorax with reticulated subcuticular strengthening. All other hyaline frills serrate ( Fig. 13 ), that of P4 laterally with reticulated subcuticular strengthening. Lateral edges of pleurotergites of somites bearing P2–P4 with spinules ( Fig. 13 G). Anterior third of P2 to P5 somites with 2 rows of spinules longer than other spinules of the body ( Fig 13 C), covered laterally by hyaline frill of the preceding segment. Penultimate segment with plain pseudoperculum. Anal somite divided.

Rostrum ( Figs 1 A–C) fused medially with cephalothorax and nearly 1.5 times longer than broad; 2 sensillae and 2 pores on dorsal surface and 2 bulbous sensillae at distal edge, each with a knob at the tip ( Fig. 12 B).

Genital field ( Fig. 2 B) with 1 median copulatory pore and 2 integumental pores; without spinules.

Caudal rami ( Figs 2 D–F, 12D–F) 1.5 times longer than wide with 7 setae; rami completely covered with spinules and outer distal edge dorsolaterally with long setules; posterior edge of rami terminating ventrally as acuminate lappet covered with spinules; all setae except naked dorsal seta VII multipinnate; seta V with stripes at base.

Antennule ( Figs 3 A–B, 12A) short and thick, 7-segmented; armature formula: 1, 10, 10+aes, 1, 3, 4, 7+aes; first segment with a row of long spinules; segments 2 and 3 making up more than half of the length; segments 1 and 4–7 broader than long; 28 of the 36 setae multipinnate, 5 bipinnate, 1 plumose, 1 naked and 1 with a row of small regular palisades.

Antenna ( Figs 4 A–B): Basis with many long spinules at lateral edge; enp-1 with 1 seta near proximal margin; enp-2 with 3 strong lateral and 6 strong distal setae, 1 lateral and 1 distal seta multipinnate; enp-2 with 3 groups of long spinules near proximal edge, at lateral side and near distal margin; exopod 3-segmented with 2, 1, 2 setae, 2 setae multipinnate and 4 bipinnate; exopod as long as endopod and as strong as enp-2, middle segment shortest; exp-1 with 2 rows of setules; exp-3 with 1 transverse row of strong spinules at distal edge and 1 field of small setules at outer side.

Labrum ( Fig. 4 C) not prominent; dorso-lateral with 1 field and 1 row of small spinules at left and right corner; ventrally equipped with 1 pore, 1 circle of long setules, and 1 field of small spinules.

Paragnaths (Paratype 1: Fig. 4 D) fused; both sides with many long and thin setules and 3 strong spinules. Mandible ( Fig. 5 A, paratype 2: Fig. 5 B): Cutting edge with 1 large and 7 smaller fused teeth, 1 bipinnate seta at proximal and 1 naked seta at distal corner; the 6 proximal of the smaller teeth multicusped; gnathobase with 1 field, 1 large row and 4 small rows of spinules; basis with 2 rows of long setules and 4 setae (2 multipinnate and 2 bipinnate); endopod 1-segmented with 3 multipinnate setae laterally, 1 seta displaced to the proximal part of the endopod and 7 distal setae; exopod 1-segmented, shorter than endopod with 4 lateral and 2 distal setae, 3 multipinnate and 3 bipinnate; exopod with 4 transverse rows of spinules.

Maxillule ( Figs 6 A–D): Arthrite of praecoxa with 2 setae on anterior surface and apically with 2 spines and 4 setae ( Figs 6 A,D), coxa with 2 apical setae on a short endite; basis with 3+4 setae on the endites; endopod with 6 setae; exopod with 2 setae, smaller than endopod; praecoxa, coxa, basis, and exopod with rows of long setules, coxa and basis also with rows of short setules.

Maxilla ( Figs 7 A–C) robust, without setae and spines twice as long as maxilliped; syncoxa with 3 endites with (2+2), 2, 3 setae, the 2 praecoxal endites fused and rows of setules and spinules on anterior surface; allobasis with 1 spine and 6 setae at distal edge (basis setae I-4, endopodal setae 9–11) and 1 field of strong setules on anterior surface; endopod indistinctly 3-segmented, segments fused anteriorly, armature formula: I+0, I+1, 3.

Maxilliped ( Fig. 5 C): Syncoxa with 2 multipinnate coxal setae at inner and outer distal corner (10+11) and 1 row of setules at outer edge; seta 10 as long as syncoxa, basis and endopod together; basis without setae but with 1 row of spinules and 1 pore on anterior surface and long setules along outer edge; endopod 1-segmented with 1 lateral and 3 distal setae.

Armature formula P1–P4: P1 ( Fig. 8 ): Coxa with a row of strong setules, a field of small spinules, and 2 rows of spinules at outer distal corner; basis with 1 row of spinules at base of outer seta, a row of long setules on anterior surface, and a row of long setules at inner distal edge; enp-1 and enp-3 equal in length and longer than enp-2; outer edge of each segment strongly spinulose; anterior and posterior surface of each segment with rows of spinules; outer, enp-2 with a pore; 2 distal, and outer seta of enp-3 multipinnate; distal inner seta also developed as spine, seta multipinnate in the middle and bipinnate at the tip and the proximal part; exp-1 longer than exp-2 and exp-3; outer edge of each segment spinulose; anterior and posterior surface of each segment with rows of spinules and setules; inner edge of exp-1 with a row of setules; exp-2 with a pore.

P2–P4 ( Figs 9–11 ): Coxa and basis with rows of spinules and setules on anterior surface; enp-1 and enp-3 equal in length and longer than enp-2; anterior surface of enp-1 with 2 rows of strong setules; anterior and posterior surface of each segment with rows of spinules and outer edge with strong spinules; outer, 2 distal, and 1 inner seta of enp-3 multipinnate; distal inner seta also developed as spine, seta multipinnate in the middle and bipinnate at the tip; exp-1 longer than exp-2 and exp-3; anterior surface of exp-1 with 1 row of setules; anterior and posterior surface of each segment with rows of spinules; outer edge of each segment strongly spinulose; inner edge of exp-1 with a row of setules; inner distal seta of exp-3 of P4 extremely small.

P5 ( Figs 2 C, 12C) small, left and right P5 separated; baseoendopod and exopod fused to form 1 plate; P5 with 6 marginal (3 endopodal and 3 exopodal) and 1 exopodal surface seta (surface seta and 3 innermost setae multipinnate; 3 outermost setae plumose); outer basal seta longest; innermost seta of baseoendopod about 2.5 times as long as the other seta of baseoendopod; innermost seta not directly situated at the inner distal corner, but displaced towards the outer edge; entire ventral surface of P5 covered with spinules; 1 pore on anterior surface and 1 on outer part of the proximal edge.

P6 ( Fig. 2 B) with 1 seta and a small knob.

Male unknown.

Variability: Body length of females varies between 1,460 and 2,135 μm (mean = 1,675 μm; n = 15).

Etymology: This species is named after the German character “Samson” of the TV show “Sesame Street” because of its big size and the unique ornamentation of body and setae.

Food: The dissected paratype 1 has remains of leg-segments and setae of a copepod in its gut. This leads to the conclusion that this species feeds on copepods at least as a part of its diet.

Figures

FIGURE 1. Parabradya samsoni sp. nov., holotype female: (A) habitus dorsal; (B) habitus lateral; (C) rostrum. Scale bars A – B = 200 µm, C = 100 µm.

FIGURE 2. Parabradya samsoni sp. nov., holotype female: (A) abdomen, ventral; (B) genital field; (C) P 5; (D) caudal ramus, ventral; (E) caudal ramus, lateral; (F) caudal ramus, dorsal. Scale bars A = 100 µm, B – F = 50 µm.

FIGURE 3. Parabradya samsoni sp. nov., holotype female: (A) antennule ventral, setae drawn in Fig. 3 B omitted; (B) antennule ventral, setae drawn in Fig. 3 A omitted. Scale bar = 50 µm

FIGURE 4. Parabradya samsoni sp. nov.: (A) holotype female, antenna; (B) holotype female, exopod of antenna; (C) holotype female, labrum; (D) paratype 1 female, paragnaths. Scale bars = 100 µm.

FIGURE 5. Parabradya samsoni sp. nov.: (A) holotype female, mandible; (B) paratype 2 female, cutting edge of mandible; (C) holotype female, maxilliped. Scale bars = 50 µm.

FIGURE 6. Parabradya samsoni sp. nov., holotype female: (A) maxillule; (B) maxillule, endites of basis; (C) maxillule; (D) maxillule, two small setae of arthrite of praecoxa and basis setae. Scale bars = 50 µm.

FIGURE 7. Parabradya samsoni sp. nov.: (A) holotype female, maxilla anterior; (B) paratype 2 female, endopod and setae of basis of maxilla, posterior; (C) holotype female, maxilla, endites of syncoxa posterior. Scale bar = 50 µm.

FIGURE 8. Parabradya samsoni sp. nov., holotype female, P 1. Scale bar = 100 µm.

FIGURE 9. Parabradya samsoni sp. nov., holotype female, P 2. Scale bar = 100 µm.

FIGURE 10. Parabradya samsoni sp. nov., holotype female, P 3. Scale bar = 100 µm.

FIGURE 11. Parabradya samsoni sp. nov., holotype female, P 4. Scale bar = 100 µm.

FIGURE 12. Parabradya samsoni sp. nov., paratype 4 A – E, paratype 5 F: (A) antennule; (B) bulbous sensilla of rostrum with knob; (C) P 5; (D) caudal rami ventral; (E) caudal rami ventrolateral; (F) caudal rami dorsolateral. Scale bars A, C – F = 20 µm, B = 1 µm.

FIGURE 13. Parabradya samsoni sp. nov., paratype 4 A, F, G, paratype 5 B – E: (A) genital double somite ventrolateral; (B) hyaline frill of cephalothorax and ornamentation of P 2 - somite, dorsolateral; (C) hyaline frill of P 2 - somite and ornamentation of P 3 - somite, dorsolateral; (D) last three abdominal somites ventrolateral; (E) hyaline frill of the genital double somite and ornamentation of following somites, ventrolateral; (F) P 2 - somite lateral; (G) lateral edge of pleurotergite of P 2 - somite. Scale bars A – F = 20 µm, G = 5 µm.