Leitoscoloplos simplex, Blake, James A., 2017

Blake, James A., 2017, Polychaeta Orbiniidae from Antarctica, the Southern Ocean, the Abyssal Pacific Ocean, and off South America, Zootaxa 4218 (1), pp. 1-145 : 19

publication ID

https://doi.org/ 10.5281/zenodo.245827

publication LSID

lsid:zoobank.org:pub:9345C596-8656-4B5C-AD8C-2FACF4E9240C

DOI

https://doi.org/10.5281/zenodo.4901745

persistent identifier

https://treatment.plazi.org/id/8F2387DD-0607-091F-FF31-FD17FD5CF88D

treatment provided by

GgServerImporter

scientific name

Leitoscoloplos simplex
status

sp. nov.

Leitoscoloplos simplex View in CoL new species

Figure 6 View FIGURE 6 D–E

Material examined. North equatorial Pacific Ocean , abyssal plain, Clarion-Clipperton Fracture Zone , NOAA BIE Sta. DDT-08-93, 0 2 September 1993, 12°55.633′N, 128°36.011′W, 0.25 m 2 box core, 4843 m, coll. D.T. Trueblood, holotype ( USNM 1407119 View Materials ) GoogleMaps .

Description. Holotype incomplete, 5.5 mm long, 0.6 mm wide across thorax for 22 setigers. Body cylindrical in cross section; parapodia lateral, abdominal parapodia only partially elevated dorsally. Thoracic and anterior abdominal segments about 4.5x as wide as long; more posterior abdominal segments about as long as wide. Thorax with eight setigers, transition to abdominal segments evident by enlargement of neuropodium and development of a ventral cirrus. Branchiae entirely absent from fragment. Pygidium unknown. Color in alcohol, light tan; no body pigment.

Prostomium conical, wide, basally tapering to rounded anterior margin; without eyespots, nuchal organs not observed ( Fig. 6 View FIGURE 6 D). Peristomium a single ring, wider than long, about 1.5x as long as anterior thoracic setigers.

Thoracic notopodia enlarged, somewhat swollen, with narrow, finger-like postsetal lobe which becomes wider basally and more triangular in shape along thoracic segments ( Fig. 6 View FIGURE 6 D); thoracic neuropodia not as large as notopodia ( Fig. 6 View FIGURE 6 D); postsetal lamellae absent on setiger 1, short, fingerlike postsetal lobe present from setiger 2 and continuing through thoracic setigers ( Fig. 6 View FIGURE 6 D); abdominal neuropodia enlarged, elongate, swollen apically with short, ventral cirrus., only partially elevated dorsally ( Fig. 6 View FIGURE 6 E).

Thoracic noto- and neurosetae long crenulated capillaries in dense fascicles of 75 or more setae. Notosetae of first 2–3 abdominal setigers similar to thoracic segments with dense fascicles of long capillaries; subsequent abdominal segments with fewer and shorter capillaries, reduced in number to 20–25 per notopodium ( Fig. 6 View FIGURE 6 D–E). Abdominal neurosetae few, reduced to 4–6 very fine capillaries; 1–2 embedded aciculae present ( Fig. 6 View FIGURE 6 E).

Etymology. The species name is from the Latin simplex and refers to the overall lack of typical orbiniid morphology.

Remarks. Leitoscoloplos simplex n. sp. is similar to L. abranchiatus in lacking branchiae, having long capillary setae in dense fascicles, and by having abdominal parapodia only weakly elevated instead shifted dorsally as in most orbiniids. These two deep-sea species differ in that L. simplex n. sp. has a peristomium with a large single ring instead of 2–3 weak lobes, has ventral cirri in abdominal neuropodia instead of lacking them, and most significantly, lacks furcate setae that are present in L. abranchiatus .

Distribution. Abyssal Pacific, 4843 m.

NOAA

National Oceanic and Atmospeheric Administration

USNM

Smithsonian Institution, National Museum of Natural History

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