Smacigastes Ivanenko & Defaye

Gollner, Sabine, Ivanenko, Viatcheslav N. & Arbizu, Pedro Martinez, 2008, A new species of deep­sea Tegastidae (Crustacea: Copepoda: Harpacticoida) from 9 ° 50 ´ N on the East Pacific Rise, with remarks on its ecology *, Zootaxa 1866, pp. 323-326: 324-332

publication ID

http://doi.org/ 10.5281/zenodo.183742

persistent identifier

http://treatment.plazi.org/id/89008784-FFCC-FF96-EAE3-8F10FC2BFBCA

treatment provided by

Plazi

scientific name

Smacigastes Ivanenko & Defaye
status

 

Genus Smacigastes Ivanenko & Defaye 

Type species Smacigastes barti  sp. nov.

Type material

Holotype dissected Ψ, 19 slides (nr. SMF 31411View Materials) Paratype 1: dissected ɗ, 13 slides (nr. SMF 31412View Materials) Paratype 2: Ψ (nr. SMF 31413View Materials)

Paratype 3: ɗ (nr. SMF 31414View Materials)

Paratype 4: Ψ (nr. SMF 31415View Materials)

Paratype 5: ɗ (nr. SMF 31416View Materials)

Paratype 6: Ψ (nr. SMF 31417View Materials)

Paratype 7: ɗ (nr. SMF 31418View Materials)

Paratype 8: dissected copepodite stage V, 3 slides (nr. SMF 31419View Materials) Paratype 9: Ψ (nr. OLML 2007 / 199)

Paratype 10: ɗ (nr. OLML 2007 / 200)

Paratype 11:Ψ (nr. OLML 2007 / 201)

Paratype 12: ɗ (nr. OLML 2007 / 202)

Paratype 13: copepodite stage V (nr. OLML 2007 / 203)

Type locality

East Pacific Rise (EPR); 9 ° 50.447 ´N, 104 ° 17.493 ´W; 2500 m depth. The site Tica is located on the EPR between the Clipperton and Sequeiros transform faults. The site was colonized by the giant tubeworm Riftia pachyptila  in 1997 ( Fornari et al. 2004). Type material was collected from artificial substrates (PVC hoses) deployed in 2002, and recovered one year later (see Govenar & Fisher 2007).

Etymology

The species is named in honor of Breea Govenar who designed the artificial devices from which specimens were collected ( BART: Breea ´s Artificial Riftia Tubes  ).

Female

Body ( Fig. 1View FIGURE 1 a, 1 b, 2 a) laterally compressed, weakly chitinized, with short sensilla and few pores. Total length of female holotype (rostrum to posterior margin of telson) 420 µm, greatest width 180 µm. Rostrum rounded and prominent ( Fig. 1View FIGURE 1 a). Prosome 4 ­segmented (cephalothorax and 3 somites bearing legs 2 to 4) (Fig. 2 a). Urosome (Fig. 2 b) 5 ­segmented: first urosomite with leg 5, genital­double somite with ventral depression and one gonoporus covered by flap of the minute leg 6 ( Fig. 1View FIGURE 1 c, 5 b, 5 c), and 2 postgenital somites plus telson with furca. Furca 3 times as long as wide, with 7 setae of different length (Fig. 2 c).

Antennule (Fig. 2 d) 7 ­segmented; formula of setation: 1, 10, 9, 3 +aesthetasc, 6, 4, 6 +aesthetasc.

Antenna (Fig. 2 e) with small coxa and elongate basis with 1 seta and a field of cuticular spinules. Exopod 2 ­segmented, proximal segment with 1 inner setae, distal segment with 3 apical setae; endopod 2 ­segmented, proximal segment with 1 median seta, distal segment with 4 inner setae, 6 terminal setae and a hyaline frill subdistally on outer margin.

Labrum (Fig. 2 a) projecting over shield of cephalothorax in lateral view.

Mandible ( Fig. 3View FIGURE 3 a) with gnathobase (not shown); palp 2 ­segmented, with 2 distal setae on basis and 1 ­segmented endopod bearing 1 outer and 3 terminal setae.

Maxillule ( Fig. 3View FIGURE 3 b, c) with praecoxal arthrite bearing 8 spines; coxal endite with 1 seta; exopod with 2 setae; basis elongate with 1 median and 4 terminal setae.

Maxilla ( Fig. 3View FIGURE 3 d) syncoxa with two endites, proximal endite with 1, distal endite with 3 spines. Allobasis with 3 lateral setae, two subdistal and one apical spine.

Maxilliped ( Fig. 3View FIGURE 3 e, f) 3 ­segmented, subchelate; syncoxa elongated with 1 distal seta; basis with 2 rows of spinules; endopod 1 ­segmented, produced into a strong claw, with 2 proximal setae and an inner row of short spinules.

Swimming legs 1–4 biramous; armature formula as in Table 1.

FIGURE 2. Smacigastes barti  sp. nov. Ψ holotype LM drawings: A, habitus, lateral (labrum indicated by arrow); B, urosome, ventral; C, furca, ventral; D, antennule (a seta on 2 nd segment broke and is indicated by a circle); E, antenna (frill indicated by arrow). Scale bars A 100 µm; B –E 50 µm.

Leg 1 ( Fig. 4View FIGURE 4 a) with 1 ­segmented rami.

Leg 2 and leg 3 ( Fig. 4View FIGURE 4 b, 4 c) with 3 ­segmented endopods and 2 ­segmented exopods; proximal segments of exopods elongated, derived by fusion of former proximal and middle segments.

Leg 4 ( Fig. 4View FIGURE 4 d) with 3 ­segmented rami. Distal exopod segment with an inner seta slightly modified into a spine ( Fig. 5View FIGURE 5 a).

Leg 5 ( Fig. 5View FIGURE 5 b) with baseoendopod and exopod; baseoendopod with 1 basal outer seta, 3 inner setae, 1 terminal spine, and 1 small terminal outer seta; exopod with 3 outer elements (proximal seta­like; middle and distal ones spine­like), and 2 terminal spines.

Leg 6 a small flap with 1 minute seta ( Fig. 5View FIGURE 5 c).

Single egg sac with three eggs, located ventrally between fifth legs ( Fig. 1View FIGURE 1 b, 1 c, 2 a).

Male differs from female in the following:

Length of paratype 1 ( Fig. 1View FIGURE 1 d, 6 a) 325 µm; greatest width 150 µm. Genital­double somite ( Fig. 1View FIGURE 1 e, 5 e) produced ventrally into a large, elongated prominence bearing a distally asymmetrical genital flap representing leg 6.

Antennule ( Fig. 6View FIGURE 6 b) 10 ­segmented; setation formula as follows: 1, 10, 6 +aesthetasc, 1, 7 +aesthetasc, 1, 2, 1, 4, 7 +aesthetasc.

Leg 5 ( Fig. 5View FIGURE 5 d) 2 ­segmented; basis with 1 outer seta, exopod with 1 outer proximal seta, 1 outer subdistal spine, and 2 terminal spines.

Leg 6 ( Fig. 1View FIGURE 1 e, 5 e) a membranous genital flap on the left side.

One spermatophore stored inside the genital­double somite ( Fig. 5View FIGURE 5 e).

Copepodite stage V

Leg 2 ( Fig. 6View FIGURE 6 c) and Leg 3 ( Fig. 6View FIGURE 6 d) consist of 3 ­segmented exopods (in contrast to adult) and 2 ­segmented endopods (shortly before division into the adult 3 ­segmented endopod).

SMF

Forschungsinstitut und Natur-Museum Senckenberg

OLML

Oberösterreichisches Landesmuseum