RETUSIDAE, Thiele, 1925
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978-2-85653-614-8 |
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https://treatment.plazi.org/id/03D087B2-FF50-BE98-FF01-77B5F265FAEC |
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Felipe (2021-09-01 00:27:07, last updated by Plazi 2023-11-06 13:30:32) |
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RETUSIDAE |
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Family RETUSIDAE View in CoL incertae sedis
REMARKS. — In this section I have included two deep-water species, only known from their shells, for which I was unable to determine a generic placement. The shell morphology of these species resembles that of Retusidae so they have been placed tentatively in this family.
Retusidae sp. 1 Figs 91A, B, 92
MATERIAL EXAMINED. — Loyalty Ridge. BIOGEOCAL: stn KG 294, 20°39’S, 167°12’E, 1420 m, 1 dd.
DISTRIBUTION. — Single specimen collected from New Caledonia (Fig. 92), in 1420 m .
DESCRIPTION. — Shell morphology. Length 4.5 mm, width 2.5 mm (single specimen examined). Shell fragile, oval to elongate, with convex sides (Fig. 91A). Only 1 whorl visible, forming the entire shell. Apex rounded, not umbilicate (Fig. 91B), with the aperture lip rising from the right side and forming a short wing that is connected to the columellar margin. Anterior end of the shell rounded. Aperture as long as the shell, wider anteriorly and narrowing abruptly at about 1/4 of its length. Columellar margin thickened. Columella smooth, with no folds. Umbilicus narrow, partially covered by an extension of the columella. Sculpture of a number of faint growth lines. Colour uniformly dirty white with a number of brown-reddish spots, more densely arranged near the posterior end of the shell.
Anatomy. Unknown. The single shell collected lacked soft parts.
REMARKS. — The shell of this species is different from other deep-water taxa examined in this study and I have been unable to find species with a similar morphology in the literature.
A generic placement for this species is not possible until complete specimens become available for study.
Retusidae sp. 2 Figs 91C, D, 92
MATERIAL EXAMINED. — Philippines. ESTASE 2: stn CP 6, 04°38’N, 119°49’E, 2570 m, 15 dd GoogleMaps .
DISTRIBUTION. — Material examined collected from the Philippines (Fig. 92), in 2570 m .
DESCRIPTION. — Shell morphology. Length 4 mm, width 3 mm (largest specimen examined). Shell solid, oval, with convex sides (Fig. 91C). Only 1 whorl visible, forming nearly the entire shell, except for a visible portion of the top of the spire. Apex rounded, deeply umbilicate (Fig. 91D), with the aperture lip rising from the right side and forming a short wing that is connected to the columellar margin. Anterior end of the shell rounded. Aperture as long as the shell, wider anteriorly and narrowing abruptly at about 1/3 of its length. Columellar margin conspicuously
FIG. 91. Shell morphology of species of Retusidae incertae sedis. A, Retusidae sp. 1, (4.5 mm), ventral view, New Caledonia, BIOGEOCAL stn KG 294; B, same shell, posterior view. C, Retusidae sp. 2, (4 mm), ventral view, Philippines, ESTASE 2 stn CP 6; D, same shell, posterior view.
thickened. Columella smooth, with no folds. Umbilicus closed. Sculpture of a number of faint growth lines. Colour uniformly dirty white.
Anatomy. Unknown. All shells collected lacked soft parts.
REMARKS. — The shells of Retusidae sp. 2 resemble that of Retusidae sp. 1, but the former are shorter, wider and have an apical umbilicus.
A generic placement for this species is not possible until complete specimens become available for study.
No known copyright restrictions apply. See Agosti, D., Egloff, W., 2009. Taxonomic information exchange and copyright: the Plazi approach. BMC Research Notes 2009, 2:53 for further explanation.
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