Capitella blakei Magalhäes & Hilliard 2022, sp. nov.
Creators: name: Magalhäes, Wagner F.
name: Hilliard, Justin
Publisher: name: Zenodo
Year: 2022
Subjects: Biodiversity
Taxonomy
Animalia
Annelida
Polychaeta
Capitellidae
Capitella
Capitella blakei

description: Capitella blakei sp. nov.
Figures 2–3
Capitella sp. nov.: Judge & Barry, 2016: Table 3 (in part).
Material examined. Holotype: Monterey Bay, California, “Deadwood 2” site, 36° 15.6768′ N, 122° 40.6790′ W, associated with deployed fragments of ginkgo (Ginkgo biloba L.), Sta. WB26, deployed on October 18, 2011 and retrieved on October 26–28, 2013 by a benthic elevator and ROV Doc Ricketts on an MBARI cruise aboard the R / V Western Flyer, 3,100 m (FMNH 15937). Paratypes same locality, date, collector and wood type as holotype (4 complete sps, FMNH 15938; 9 anterior fragments, FMNH 15939).
Additional non-type material examined: Same locality, date and collector as type series, associated with ginkgo (Ginkgo biloba), Sta. WB25 (1 complete); associated with Spicebush (Calycanthus occidentalis Hook. & Arn.), Sta. WB20 (2 complete, 4 anterior end fragments), Sta. WB26 (5 complete, 10 anterior fragments). North Pacific, Dive R740-14 - 1 A, SRZ Axial Volcano, 45° 56.021′ N, 129° 58.962′ W, 40 m N of marker 33, wood debris, 3 Sep 2003, 1,525 m, coll. J. Marcus (7, FMNH 9997: 3 complete, 4 anterior fragments, several posterior fragments); North Pacific, Dive R740-14 - 1 B, SRZ Axial Volcano, 45° 56.021′ N, 129° 58.962′ W, wood debris, 40 m N of marker 33, 3 Sep. 2003, 1,525 m, coll. J. Marcus (8, FMNH 12608: 2 complete and 6 anterior fragments, one large individual with intratubular embryos of different size); North Pacific, Dive R740-14 - 1 C, SRZ Axial Volcano, 45° 56.021′ N, 129° 58.962′ W, 40 m N of marker 33, wood debris, 3 Sep. 2003, 1,525 m, coll. J. Marcus (2, FMNH 10005: one specimen with brown pigmentation); North Pacific, Endeavour Segment, Juan de Fuca Ridge, 47° 56.793′ N, 129° 5.838′ W, on oak and fir blocks deployed 24 months before, Dive 4045, forward port gray box; 2 Sep. 2004, 2,213 m, coll. J. Voight (2, FMNH 12920); North Pacific, Endeavour Segment, Juan de Fuca Ridge: Dive 4045, aft port gray box, 2 Sep. 2004, coll. J. Voight (1 complete, FMNH 12914); North Pacific, Endeavour Segment, Juan de Fuca Ridge, 47° 56.793′ N, 129° 5.838′ W, on oak and fir blocks deployed 24 months before, Dive 4045, forward port gray box; 2 Sep 2004, 2,213 m, coll. J. Voight (1, FMNH 12926: anterior fragment); North Pacific, Endeavour Segment, Juan de Fuca Ridge, 47° 56.793′ N, 129° 5.838′ W, Dive 4045, forward port gray box, 2 Sep 2004, on oak and fir blocks deployed 24 months before, 2213 m, coll. J. Voight (1, FMNH 13049: anterior fragment); North America, North Pacific, U.S.A., 44° 45′ 29″N, 125° 32′ 10″ W, Sta. 1, off the coast of Oregon, wild wood fall, 16 Apr 1997, 2,850 m, coll. J. Voight (4, FMNH 14438: 1 large anterior fragment and 3 juveniles, large animal with several attached embryos); North Pacific: Dive 4046, port forward gray box; near Wuzza Bear Mount, 3 Sep. 2004, coll. T. A. Haney (1, FMNH 12983).
Description. All specimens, including holotype, with external male features. Holotype complete, 13 mm long, 1.4 mm wide for 42 chaetigers. Paratypes ranging from 13–20 mm long, 1.5–2.2 mm wide for 44–52 chaetigers. Body short and thick, wider on mid-thoracic chaetigers; body rounded dorsally and with deep lateral and ventral grooves beginning from chaetiger 4–5 and present throughout. Color in alcohol pale yellow to tan.
Prostomium conical with rounded tip and slightly flattened dorso-ventrally (Figs 2A, B; 3A, D); eyes absent, nuchal organs not observed. Peristomium clearly distinct from prostomium, slightly longer than chaetiger 1 and partially withdrawn (Figs 2A; 3A). Proboscis not observed.
Thorax with nine segments, epithelium smooth, not distinctly biannulate (Figs 2A, B; 3A, D); all specimens with chaetigers 1–7 having two rows of 8–10 unilimbate capillaries each. Thoracic segments widest on chaetiger 5, tapering to chaetiger 7; chaetiger 9 greatly enlarged dorsally (Figs 2A; 3A, D). Thoracic chaetiger 8 with 8–16 notopodial genital spines and 20–25 neuropodial hooded hooks; thoracic chaetiger 9 with 6–9 notopodial genital spines and 20–25 neuropodial hooded hooks. Genital spines of chaetiger 8 in two groups, curved distally (Figs 2C; 3B); spines of chaetiger 9 also in two groups, wider and flattened basally and curved distally (Figs 2D; 3C). Spines of chaetiger 8 protruding with tips and spines of chaetiger 9 deeply embedded and never exposed in preserved specimens (Fig. 3A).
Abdominal segments multiannulated, as long as thoracic segments, with short hooded hooks throughout (Fig. 2A). Noto- and neuropodia with well separated glandular tori throughout; notopodial tori dorso-lateral and neuropodial tori ventro-lateral. Abdomen with 25–30 hooded hooks in a row; hooks similar on thorax and abdomen—with moderate shaft, hoods not extending beyond main fang, with distinct constriction on shaft and 5–6 rows of teeth above main fang (Fig. 2E, F).
Pygidium simple, anus terminal.
Methyl Green Staining Pattern. Prostomium, peristomium and chaetigers 1–5 staining lightly (Fig. 3D); chaetigers 6–9 with dark stain; chaetiger 9 staining darker laterally than on dorsal inflation. Abdominal segments staining darkly around notopodial and neuropodial tori. Segmental region of anterior 4–5 segments uniformly stained whereas the rest of abdominal segmental region was largely unstained (Fig. 3D). Pygidium staining with light green.
Etymology. This species is named after Dr. James Blake because of his numerous contributions to capitellid taxonomy including the redescription of Capitella capitata (Fabricius, 1780), which has set the scene for other Capitella species to be described. Dr. J. Blake has also been an inspiration to the author (WM) for his comprehensive taxonomic work and beautiful line drawing illustrations.
Remarks. Capitella blakei sp. nov. belongs to a group of Capitella species having individuals with external male characteristics with chaetigers 1–7 having notopodial and neuropodial capillaries: C. amboensis Pamunkgas, 2017, C. capitata (Fabricius, 1780) sensu Blake (2009), C. perarmata (Gravier, 1911), C. singularis (Fauvel, 1932) and C. teleta Blake, Grassle & Eckelbarger, 2009. Dissections did not reveal any internal female anatomy. Capitella blakei sp. nov. is readily distinct from these species by the presence of a peristomium clearly separated from prostomium and deep lateral and ventral grooves (from chaetigers 4–5 and present throughout). Capitella singularis has the peristomium forming a complete ring but lacks a lateral groove on body segments. According to Fauvel (1932) and Magalhães & Bailey-Brock (2012), C. singularis has branchiae on posterior segments (Fauvel 1932; Magalhães & Bailey-Brock 2012). Neotype of Capitella capitata sensu Blake (2009) is similar to C. blakei sp. nov. in regards to the presence of deep lateral and ventral grooves from chaetiger 4 but distinct in a number of features including the MGSP. The neotype of C. capitata stains predominantly on thoracic chaetigers, the abdominal segments not staining with exception of minute speckles (Blake 2009). The holotype of C. blakei sp. nov. has a light staining on thoracic chaetigers 1–5 and distinct staining around the abdominal parapodial tori (see Fig. 3D).
Capitella blakei sp. nov. is a deep-sea species widely distributed in the northeastern Pacific occurring in 1,525 – 3,100 m depths. Capitella iatapiuna (whale bones, 4,204 m) and Capitella aberranta (4,862 m) are two Atlantic abyssal species that are readily distinguishable from C. blakei sp. nov. by the shape of prostomium/peristomium, thoracic chaetal formulae and types of chaetae (Hartman & Fauchald 1971; Silva et al. 2016).
Distribution. Type locality is Monterey Bay, off California, U.S. in 3,100 m depth. This species is widely distributed across abyssal depths in the northeastern Pacific from wood deployments at the edge of a hydrothermal vent in the Cascadia Basin (Wuzza Bare site) and Juan de Fuca Ridge (Axial volcano and Endeavour sites) and wild wood falls in the Oregon Margin at 1,525 –2,850 m depths (Fig. 1).
description: Published as part of Magalhäes, Wagner F. & Hilliard, Justin, 2022, Two new deep-sea species of Capitella (Annelida: Capitellidae) from sunken wood in the Northeast Pacific, pp. 229-240 in Zootaxa 5125 (2) on pages 231-234, DOI: 10.11646/zootaxa.5125.2.7, http://zenodo.org/record/6424594