Parexogone wolfi Boggemann & Purschke 2005
- Dataset
- Syllidae (Annelida: Phyllodocida) from the deep Mediterranean Sea, with the description of three new species
- Rank
- SPECIES
Classification
- kingdom
- Animalia
- phylum
- Annelida
- class
- Polychaeta
- order
- Phyllodocida
- family
- Syllidae
- genus
- Parexogone
- species
- Parexogone wolfi
description
Description. All individuals lacking pygidium; two with regenerating anterior end. Best preserved individual ca. 6 mm long for 40 chaetigers, 0.20 mm wide. Prostomium wider than long, often hidden under dorsal part of peristomial segment, four rounded, relatively large eyes in trapezoidal arrangement (absent in regenerating individuals). Palps ca. twice as long as prostomium, entirely fused, clearly pointed; antennae well-developed, median one slightly longer than palps, lateral antennae ca. half as long as median one. Dorsal cirri oval, small, present in all chaetigers. Parapodia well-developed, with 8 – 14 compound chaetae, blades bidentate. Two spinigerlike chaetae with distinctly long, slightly sinuous blade (45 – 55 µm in the anterior part, 50 – 70 µm in the midbody, 30 – 45 µm in the posterior part of the body), with a strong serration in the distal part, less evident towards basal part (Fig. 5 b). Several falcigers on each parapodium, with distinctly shorter blades and strong serration, with some longer spines distally, decreasing in size from the dorsal part of parapodium to the ventral one, approximately 15 – 25 µm in the anterior part of the body, 10 – 20 µm in the midbody, 15 – 8 µm in the posterior part of the body (Fig. 5 c). Pharynx slender, longer than proventriculum, through 4 segments, bearing a strong, triangular tooth on anterior margin; proventricle short, through two segments approximately, with 15 – 17 cell rows.
discussion
Remarks. Parexogone wolfi is one of the most widespread deep-water Exogoninae and shows remarkably wide depth range adaptation (San Martín 2003). The available descriptions, however, highlight slight differences between individuals from different areas, which might represent a clue of cryptic speciation (Barroso et al. 2017). For instance, shallow water (8 m depth) Pacific individuals are distinctly thinner, with a couple of additional eyespots and shorter spiniger-like chaetae in respect to the original description (San Martín 2005), which in our opinion suggests that they may represent an undescribed species.
distribution
Distribution. Western Atlantic Ocean (San Martín 1991; Barroso et al. 2017); Eastern Atlantic Ocean (San Martín et al. 1996; Böggemann 2009); Pacific Ocean (dubious) (San Martín 2005); Eastern Mediterranean Sea (Simboura & Zenetos 2005); from ca. 100 m depth (Simboura & Zenetos 2005) to more than 5000 m depth (Böggemann 2009). This is the first record of the species for the Western Mediterranean.
materials_examined
Material examined. St. 8: 4 individuals. St. 16: 3 individuals. St. 19: 2 individuals.