Pseudoscalibregma Ashworth 1901
Genus Pseudoscalibregma Ashworth, 1901 Type-species: Scalibregma parvum Hansen, 1879. Diagnosis. Body elongate, arenicoliform. Prostomium T-shaped with lateral horns. Peristomium achaetous, surrounding prostomium dorsally and forming upper and lower lips of mouth ventrally. Parapodia of posterior se...
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| Format: | Other/Unknown Material |
| Language: | unknown |
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2015
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| Online Access: | https://zenodo.org/record/6102455 https://doi.org/10.5281/zenodo.6102455 |
| Summary: | Genus Pseudoscalibregma Ashworth, 1901 Type-species: Scalibregma parvum Hansen, 1879. Diagnosis. Body elongate, arenicoliform. Prostomium T-shaped with lateral horns. Peristomium achaetous, surrounding prostomium dorsally and forming upper and lower lips of mouth ventrally. Parapodia of posterior segments with dorsal and ventral cirri; interramal papillae present; postsetal lamellae absent. Branchiae absent. Setae include capillaries, lyrate setae, and sometimes few inconspicuous spinous setae among capillaries of setigers 1‒2, blunt, pointed, or bifurcated, representing homologues of lyrate setae; large conspicuous spines absent. Pygidium with long anal cirri. Remarks. Apart from a more variable morphology of dorsal and ventral cirri, the only character that separates Pseudoscalibregma from Scalibregma is the absence of branchiae. The presence of short spinous setae in the first 1‒2 setigers as occurs in species of Scalibregma was confirmed by Imajima (2009) as part of his description of P. orientalis Imajima, 2009 from Japan and Bakken et al. (2014) as part of their redescription of the type species, P. parvum. I can also confirm after a re-examination of the holotype that P. usarpium Blake, 1981 from Antarctica also has these setae. Four species of Pseudoscalibregma have been reported from Antarctic seas: (1) P. bransfieldium (Hartman, 1967), (2) P. usarpium, (3) P. papilla Schüller, 2008, and (4) P. h ar t m a na e (Blake, 1981), new combination. A fifth species was found in the LIS-A collections and is described here. Additional descriptive notes are provided for P. bransfieldium. Character⁄Nο. Setigers 10 14 ̶ 15 16 17 ̶ 18 20 22 ̶ 24 28 30 Length 630 μm 850 ̶ 900 μm 945 ̶ 990 μm 960 ̶ 1,221 μm 1300 ̶ 1875 μm 2.6 ̶ 2.8 mm 3.5 mm 5.67 mm Width 70 μm 220 ̶ 232 μm 305 ̶ 325 μm 353 ̶ 407 μm 450 ̶ 580 μm 0.62 mm 0.75 mm 0.95 mm Prοstοmium Bulbοus,rοunded Bulbοus, Rοunded, Inflated, lateral Becοming wide, Brοad, thickened Lateral hοrns well Lateral hοrns fully extended apically pοinted apically bulges, tapering ... |
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