Asterocheres tenerus Hansen 1923
Asterocheres tenerus (Hansen, 1923) (Figs 2–4) Ascomyzon tenerum Hansen 1923: 7. Asterocheres tenerus: Stock 1966 b: 152; Johnsson 1998: 92. Material examined. Holotype Ψ and 8 paratypes (5 Ψ and 3 ɗ) (ZMUC. CRU- 8357) collected during the “Danish Ingolf Expedition” in Davis Strait, Station 25 (63 º...
| Main Authors: | , |
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| Format: | Other/Unknown Material |
| Language: | unknown |
| Published: |
2009
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| Subjects: | |
| Online Access: | https://zenodo.org/record/6221578 https://doi.org/10.5281/zenodo.6221578 |
| Summary: | Asterocheres tenerus (Hansen, 1923) (Figs 2–4) Ascomyzon tenerum Hansen 1923: 7. Asterocheres tenerus: Stock 1966 b: 152; Johnsson 1998: 92. Material examined. Holotype Ψ and 8 paratypes (5 Ψ and 3 ɗ) (ZMUC. CRU- 8357) collected during the “Danish Ingolf Expedition” in Davis Strait, Station 25 (63 º 30 ΄N, 54 º 25 ΄W), at 582 fathoms depth (ca. 1.06 km). Redescription of adult female: Body (Fig. 2 A) cyclopiform, with oval cephalothorax and cylindrical urosome. Total length 904 µm (n = 1); maximum width 452 µm. Ratio of length to width of prosome 1.5: 1. Ratio of length of prosome to urosome 2.6: 1. Prosome comprising cephalothorax fully incorporating first pedigerous somite and 3 free pedigerous somites. Pedigerous somite 4 much smaller and narrower than preceding somites. Dorsal cephalothoracic shield and free pedigerous somites ornamented with integumental pores and sensillae (these features not shown in Fig. 2 A). Urosome (Fig. 2 B) 4 -segmented, comprising pedigerous somite 5, genital double-somite and 2 free abdominal somites. Genital double-somite and following somites furnished with large spinules. Pedigerous somite 5 narrow, largely concealed under tergite of pedigerous somite 4, with spinular row on each side of dorsal midline. Genital double-somite about as long as wide, with separate genital apertures, each comprising ventrolateral copulatory pore and dorsolateral gonopore (oviduct opening); lateral margins with rows of setules posterior to genital apertures. Caudal rami longer than wide, armed with 6 setae (seta I absent); setae III–VI arranged along posterior margin; setae II and VII inserted subapically on dorsal surface. Antennule (Fig. 2 C) 21 -segmented, 544 µm long. Segmental homologies (expressed segment given first followed by ancestral segment(s) in brackets) and setation pattern as follows: 1 (I)- 2, 2 (II)- 2, 3 (III)- 2, 4 (IV)- 2, 5 (V)- 2, 6 (VI)- 2, 7 (VII)- 2, 8 (VIII)- 2, 9 (IX–XII)- 7, 10 (XIII)- 2, 11 (XIV)- 1 +spine, 12 (XV)- 2, 13 (XVI)- 2, 14 (XVII)- 2, 15 (XVIII)- 2, 16 (XIX)- ... |
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