Fauveliopsis rugosa Fauchald, 1972b

Salazar-Vallejo, Sergio I., Zhadan, Anna E. & Rizzo, Alexandra E., 2019, Revision of Fauveliopsidae Hartman, 1971 (Annelida, Sedentaria), Zootaxa 4637 (1), pp. 1-67 : 34-35

Fauveliopsis rugosa Fauchald, 1972b

Figures 19 , 20

Fauveliopsis rugosa Fauchald, 1972b: 220–222 , Pl. 45, Figs. a–e; Méndez 2006: 781, Tab. 2, page 779.

TL: Off Natividad Island, Baja California, México, 1740 m. D: Cedros Island to Marías Islands, México, 820–2650 m .

Type material: Northeastern Pacific Ocean. Western Mexico. Holotype ( LACM 990 ) and 8 paratypes ( LACM 991 ), off Isla Natividad, Baja California, R/ V Velero IV, Sta. 7229 (27°54’25” N, 115°40’00” W), 1751– 1724 m, green mud, 31 Dec. 1960 (paratypes four complete, three with body segments long; body 2.1–5.2 mm long, 0.3–0.8 mm wide, 23–30 chaetigers; GP or oocytes not seen).

Additional material. Northeastern Pacific Ocean. Western Mexico. One specimen ( LACM 7588 ), off Natividad Island, R / V Velero IV, Sta. 7229 (27°54’25” N, 115°40’00” W), 1751, green mud, piston corer, 31 Dec. 1960 (twisted, posterior region broken, lost; GP or oocytes not seen) . One specimen ( LACM 7590 ), off Natividad Island, R / V Velero IV, Sta. 7236 (27°44’33” N, 115°24’ 05” W), 540 m, mud, rock, piston corer, 2 Jan. 1961 (twisted, difficult to measure; GP on posterior margin of chaetiger 12; oocytes loosely floating in coelom, visible towards posterior region)

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Diagnosis. Fauveliopsis with 23–35 chaetigers. Anterior chaetigers with a transverse series with 5–6 spherical papillae. Ventral integument rugose. Interramal papillae pyriform, pedunculate. First chaetiger with larger aciculars in both rami, slightly larger in neuropodia. Median chaetigers with one acicular and one capillary per bundle. Chaetal formula: 1A1–2c/1–2c1A (ant.), 1A1c/1c1A (med.), 1A1c/1c1A (post.). GP on right side of chaetiger 12.

Observations. Holotype (LACM 990) an anterior fragment with 10 very long chaetigers (originally complete, 5.5 mm long, 0.5 mm wide, 35 chaetigers). Body cylindrical, slightly swollen anteriorly ( Fig. 19A, B ), segments slightly longer than wide, progressively longer ( Fig. 19C ); integument rugose with 5–6 rings, and additional larger papillae. Prostomium and peristomium not exposed. First four chaetigers with one acicular and one capillary per rami, aciculars curvature progressively attenuated, becoming almost straight by chaetiger 5. Chaetigers 5–11 longer, 2–4 times longer than wide, with segments 6–8 the longest. GP single, right posterior margin of chaetiger 9, just before chaetae of chaetiger 10 ( Fig. 19D ). Posterior region sometimes damaged, different from a shield or other anchoring modification.

Observations by SEM of two other specimens allow some additional comments. There are three anterior chaetigers with aciculars, and capillaries start from chaetiger 4 ( Fig. 20A ). Body integument rugose throughout venter ( Fig. 20A, C, G ), but variable in posterior region depending upon the fixation was made over a smooth surface; if so, venter smoother ( Fig. 20 E, F ), and anal plate subpentagonal with three larger papillae above anus and marginal papillae along the upper and lateral margins ( Fig. 20G ). Genital papilla digitate, on right side, placed in posterior margin of chaetiger 12 ( Fig. 20A , B–D).

Remarks. Fauveliopsis rugosa differs from other species in the genus having only two chaetae per rami and more than 15 chaetigers, by having body surfaces with different rugosity; its dorsum is rugose, and its venter is papillated.

Chaetal features were apparently confused in the original description ( Fauchald 1972b:221): “the first setiger has one large spine in each neuropodium, each of the first notopodia has 2 thinner spines.” The holotype is an anterior fragment with segments 1.5 times longer than wide. The paratypes include eight specimens. An interesting derivation of these apparently relaxed specimens is that fauveliopsids could considerably extend their bodies without leaving their shelter. This can explain the observations of specimens regenerating their anterior ends. Méndez (2006:781) found members of this species in scaphopod shells ( Fissidentalium megathyris or Rhabdus dalli ).

Figures

FIGURE 19. Fauveliopsis rugosa Fauchald, 1972b, holotype (LACM 990). A. Anterior end fragment, oblique dorsal view. B. Same, oblique ventral view. C. Anterior region, oblique lateral view. D. Last chaetiger (inset: close up of genital papilla; arrows point to genital papillae). Scale bars: A: 0.8 mm, B: 0.7 mm, C: 110 µm, D: 90 µm.

FIGURE 20. Fauveliopsis rugosa Fauchald, 1972b, non-type specimen (Scamit 85203): A. Anterior region, right lateral view, genital papilla in chaetiger 12. B. Same, anterior region, ventral view (asterisk indicates segments enlarged in C). C. Same, chaetigers 12–13, ventral view. D. Same, chaetigers 11–13, right lateral view, showing genital papilla. E. Posterior end, right lateral view. F. Posterior region. G. Close-up of collapsed pygidium taking a subpentagonal shape. Scale bars: A: 150 µm, B: 60 µm, C: 150 µm, D: 140 µm, E: 120 µm, F: 0.6 mm, G; 70 µm.