Heterospio longissima Ehlers, 1874 sensu Hartman 1965

• Main Authors: Parapar, Julio, Aguirrezabalaga, Florencio, Moreira, Juan
• Format: Other/Unknown Material
• Language: unknown
• Published: Zenodo 2014
• Subjects: Biodiversity; Taxonomy; Animalia; Annelida; Polychaeta; Spionida; Longosomatidae; Heterospio; Heterospio longissima; Iceland
• Online Access: https://doi.org/10.5281/zenodo.4324093; http://treatment.plazi.org/id/547B87D09B5CC94CFEACB11FFCAE0EC3

Heterospio longissima Ehlers, 1874 sensu Hartman (1965) (Figures 1–4, 5B, 7A, 8) Heterospio longissima. Hartman, 1965: 163–164, fig. 30 f–h. Material examined Five incomplete specimens were collected in three BIOICE samples (Table 1). BIOICE sample 2414 (1 spec. in SEM stub, IINH27830); BIOICE sample 2474 (1 spec. in SEM stub, IINH27830); BIOICE sample 3500 (3 spec., IINH27831). Description Most complete specimen 9 mm long, 0.4 mm wide, with 14 chaetigers. Prostomium conical, anteriorly rounded, slightly flattened dorsoventrally (Figure 2A, B). Eyes absent. Nuchal organs as deep grooves posterolateral to prostomium. Peristomial palps and palp scars not observed. Pharynx sac-like, eversible and unarmed. Anterior body region slightly flattened dorsoventrally, with eight short chaetigers (CH) (Figures 2A, B, 5B). CH 1–8 short, somewhat more than twice as wide as long. Chaetigers progressively longer from CH 9 onwards. CH 9 first elongated segment, longer than wide; length (as distance from chaetal bundle to chaetal cincture of CH 10) about three times longer than CH 8. Branchiae lacking in all specimens but eight pairs of branchial scars present from CH 2 to CH 9 (Figures 2A, B, 5B). CH 1 abranchiate (no scars). The remaining chaetigers strongly elongated and cylindrical in cross-section; length increasing backwards; CH 10 about four times longer than CH 9, CH 11 about 2.5 times longer than CH 10. CH 1–9 with biramous parapodia; with notopodial and neuropodial chaetal fascicles well separated. From CH 10 onwards parapodia as elongated ridges forming a nearly closed flange-like cincture near anterior margin of segment (Figures 2A, B, 3, 5B). Chaetae of CH 1–9 simple capillaries, in fan-shaped fascicles (Figure 2C). No neuropodial hooks in any anterior chaetiger. From CH 10 onwards chaetae arranged in two rows (Figures 2D, 4A,B): anterior row of thick subuluncini (Figure 4D–H) and posterior row of simple fine capillaries (Figure 4C). Aristate or acicular spines not observed. Occurrence In Iceland H. longissima sensu ...