Scoloplos sparsaciculus, Blake, 2020

Blake, James A., 2020, New species and records of deep-water Orbiniidae (Annelida, Polychaeta) from the Eastern Pacific continental slope, abyssal Pacific Ocean, and the South China Sea, Zootaxa 4730 (1), pp. 1-61 : 31-35

publication ID

https://doi.org/ 10.11646/zootaxa.4730.1.1

publication LSID

lsid:zoobank.org:pub:7F4CD129-9FF9-4593-A8A4-DB999B3E402F

persistent identifier

https://treatment.plazi.org/id/9A1A7DEE-1881-4BD5-BAF7-CE046F4EEF52

taxon LSID

lsid:zoobank.org:act:9A1A7DEE-1881-4BD5-BAF7-CE046F4EEF52

treatment provided by

Plazi

scientific name

Scoloplos sparsaciculus
status

sp. nov.

Scoloplos sparsaciculus View in CoL new species

Figures 15–16 View FIGURE 15 View FIGURE 16

urn:lsid:zoobank.org:act:9A1A7DEE-1881-4BD5-BAF7-CE046F4EEF52

Material examined. South China Sea, off Brunei, Island of Borneo, Site CA1 , R / V Emma , coll. J.A. Blake, box corer, Sta. 50, 2 Jun 2011, 5°42.932′N, 114°12.392′E, 1214 m, holotype ( MCZ 153591 View Materials ); Sta. 41, 3 Jun 2011 GoogleMaps ,

5°43.452′N, 114°11.302′E, 1268 m, 1 paratype ( MCZ 153592 View Materials ); Sta. 11, 6 Jun 2011 GoogleMaps , 5°50.464′N, 114°10.949′E, 1405 m, 2 specimens ( MCZ 153593 View Materials ); Sta. 36, 3 Jun 2011 GoogleMaps , 5°46.07′N, 114°12.158′E, 1313 m, 1 specimen ( MCZ 153594 View Materials ); Sta. 39, 3 Jun 2011 GoogleMaps , 5°41.492′N, 114°07.681′E, 1443 m, 1 specimen ( MCZ 153595 View Materials ); Sta. 44, 2 Jun 2011 GoogleMaps , 5°47.387′N, 114°15.605′E, 1294 m, 1 specimen ( MCZ 153596 View Materials ); Sta. 48, 2 Jun 2011 GoogleMaps , 5°45.482′N, 114°15.391′E, 1219 m, 1 specimen ( MCZ 153597 View Materials ); Sta. 61, 31 May 2011 GoogleMaps , 5°40.548′N, 114°13.261′E, 1050 m, 1 specimen ( UBD).— Site CA2 , R / V Emma , coll. P.A. Neubert, box corer, Sta. DA 3, 3 Jul 2011 GoogleMaps , 5°25.251′N, 113°29.509′E, 1772 m, 3 paratypes ( MCZ 153598 View Materials ); Sta. JA1, 30 Jun 2011 GoogleMaps , 5°28.376′N, 113°36.642′E, 1888 m, 1 specimen MCZ 153599 View Materials ); Sta. JA4, 30 Jun 2011 GoogleMaps , 5°30.906′N, 113°37.352′E, 1967 m, 1 paratype ( MCZ 153600 View Materials ); Sta. JA6, 30 Jun 2011 GoogleMaps , 5°31.035′N, 113°36.46′E, 1999 m, 1 specimen ( MCZ 153601 View Materials ); Sta. ME5, 25 Jun 2011 GoogleMaps , 5°18.475′N, 113°33.071′E, 1572 m, 1 specimen ( MCZ 153602 View Materials ); Sta. SE2, 29 Jun 2011 GoogleMaps , 5°31.362′N, 113°42.309′E, 1955 m, 1 specimen ( MCZ 153603 View Materials ); Sta. SE5, 28 Jun 2011 GoogleMaps , 5°35.739′N, 113°47.115′E, 1947 m, 1 specimen ( MCZ 153604 View Materials ); Sta. TA4 , 2 Jul 2011 GoogleMaps , 5°26.28′N, 113°26.45.6′E, 1954 m, 1 specimen ( UBD) .

Description. All specimens incomplete, most small, less than 3 mm long. Holotype with 56 setigers, 13.7 mm long, 0.4 mm wide across thoracic setigers; paratype from Sta. 41 (MCZ 153592), with 54 setigers, 7.85 mm long, 0.38 mm wide across thorax. All specimens with elongate, narrow bodies ( Figs. 15A View FIGURE 15 , 16A View FIGURE 16 ), cylindrical in cross section. Most with thoracic and anterior setigers well preserved and intact; posterior segments variable, often with podial lobes and setae damaged. With 9–12 thoracic segments, actual number size related. Thoracic segments narrow, but only about 2.5 times wider than long ( Fig. 15A View FIGURE 15 ); abdominal segments longer, about twice as long as wide. Color in alcohol: light tan.

Pre-setiger region triangular ( Figs. 15A View FIGURE 15 , 16 View FIGURE 16 A–B). Prostomium conical, narrowing to rounded tip; nuchal organs oval openings on posterior lateral margin ( Figs. 15A View FIGURE 15 , 16B View FIGURE 16 ); eyespots absent. Peristomium about 1½ times longer than first setiger, with one smooth annular ring ( Fig. 15A View FIGURE 15 ). Proboscis with 2–3 thin lobes when everted.

Thoracic notopodia swollen with a digitiform postsetal lamella ( Fig. 15B View FIGURE 15 ), short at first, then becoming long, narrow in posterior thoracic segments ( Fig. 15A View FIGURE 15 ). Thoracic neuropodia similar, with postsetal lamella shorter, thick- er ( Figs. 15B View FIGURE 15 , 16C View FIGURE 16 ). Transition to abdominal segments abrupt, with fewer noto- and neurosetae. Thoracic notopodia transitioning in abdomen to short, triangular setal lobe with a long, narrow, finger-like postsetal lamella, often with a swollen or bulbous apex ( Fig. 15C View FIGURE 15 ). A short interramal process present on a few anterior and middle abdominal setigers ( Fig. 15C View FIGURE 15 ). Neuropodia elongate, thickened, rounded apically with short, narrow ventral cirrus ( Figs. 15C View FIGURE 15 , 16E View FIGURE 16 ); narrow subpodial flange present ventral to neuropodium followed by short subpodial papillate lobe ( Fig. 15C View FIGURE 15 ), sometimes paired in a few transitional setigers. Subpodial papillae not observed on smallest specimens.

Branchiae from last thoracic setiger or an anterior abdominal setiger, usually from setiger 11–14, short at first ( Fig. 15A View FIGURE 15 ), becoming longer, tapering, sometimes asymmetrical, with subapical enlargement ( Fig. 15C View FIGURE 15 ).

Thoracic notosetae numerous thick, camerated or bristled capillaries arranged in 3–4 rows. Thoracic neurosetae with about 3–4 rows of similar camerated capillaries ( Fig. 16 View FIGURE 16 C–D), with posterior row also containing 1–3, rarely 4, inconspicuous uncini ( Figs. 15B View FIGURE 15 , 16 View FIGURE 16 C–D). Individual uncini with smooth shafts and two rows of small barbs or camerations along one side ( Figs. 15D View FIGURE 15 , 16 View FIGURE 16 C–D), tapering to narrow pointed tip; camerations not visible in some views ( Fig. 15E View FIGURE 15 ). Abdominal notosetae thin, camerated capillaries. Abdominal neurosetae with 2–3 thin capillaries and a single curved acicula, sometimes protruding, with rounded tip ( Fig. 15C View FIGURE 15 ). Furcate and flail setae not observed.

Pygidium not observed.

Methyl Green stain. Prostomium not staining, rest of body stains uniformly with no pattern.

Remarks. Comparative comments for S. sparsaciculus n. sp. and the closely related S. californiensis n. sp. are discussed in the Remarks section for the latter species (above). Scoloplos sparsaciculus n. sp. and S. californiensis n. sp. both have only a few uncini in thoracic neuropodia. Most species of the genus recorded from the Pacific have two or more rows of uncini that are mixed with numerous longer capillaries ( Hartman, 1957). In addition, both species have a subpodial flange and one or two subpodial lobes ventral to the neuropodium in anterior and some middle abdominal setigers.

Scoloplos sparsaciculus n. sp. is similar to S. intermedius ( Hartman, 1965) from slope depths off New England in having 12 thoracic setigers, branchiae from setiger 11, and a subpodial flange and subpodial papillae in abdominal neuropodia. S. intermedius , however, has an interramal cirrus on anterior abdominal parapodia ( Hartman, 1965; Mackie 1987); an interramal process is also present on a few anterior abdominal segments of S. sparsaciculus n. sp. but this is low, inconspicuous and not always observed. The two species differ most conspicuously in that the tip of the shaft of some thoracic neuropodial uncini of S. intermedius has an apical hood, and furcate setae are present in abdominal notopodia; in contrast, S. sparsaciculus n. sp. has no hood on the tip of thoracic neuropodial uncini and furcate setae are entirely absent. Scoloplos intermedius is being redescribed in another paper dealing with U.S. Atlantic deep-water orbiniids (Blake, in preparation).

Etymology. The epithet is from the Latin sparsus for few, and acicula for small pin or needle, referring to the reduced number of acicular spines or uncini found in thoracic neuropodia of this species.

Distribution. South China Sea, off Brunei, Island of Borneo, 1219–1955 m.

R

Departamento de Geologia, Universidad de Chile

V

Royal British Columbia Museum - Herbarium

Kingdom

Animalia

Phylum

Annelida

Class

Polychaeta

Family

Orbiniidae

Genus

Scoloplos

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