Yoldiella umbostriata Hoffman & Little, 2025
|
publication ID |
https://doi.org/10.4202/app.01179.2024 |
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persistent identifier |
https://treatment.plazi.org/id/4019EF34-4E7C-FF84-CC09-FF0477843722 |
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treatment provided by |
Felipe |
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scientific name |
Yoldiella umbostriata Hoffman & Little |
| status |
sp. nov. |
Yoldiella umbostriata Hoffman & Little sp. nov.
Fig. 14 View Fig .
Zoobank LCID: urn:lsid:zoobank.org:act:40B9B90E-1FB5-42F7-811D-4EFEAB577ED6 .
Etymology: After the striated sculpture on the prodissoconch.
Type material: Holotype, one shell, SMF373114 About SMF . Paratypes, six shells, SMF373113 About SMF ; one shell, SMF373116 About SMF ; one valve, SMF373117 About SMF ; two shells, SMF373115 About SMF , from the type locality and horizon.
Type locality: Northern Indian Ocean, Krishna-Godavari Basin , Bay of Bengal, offshore eastern India, 15°51.6335’ N, 81°50.2274’ E, 1046 m water depth GoogleMaps .
Type horizon: 16.18–16.88 mbsf level, core NGHP-01-12A; Upper Pleistocene .
Material.— Type material and several specimens from core NGHP-01-12A (for details see Table 1).
Diagnosis.—Small protobranch, solid, equivalve, inequilateral shell oblong outline, beaks anteriorly, smooth. Sculpture prodissoconch with parallel lines.
Dimensions.— Holotype height 1.6 mm, length 2.5 mm, tumidity 1.0 mm. Maximum dimensions of shells in type set height 2.2 mm, length 3.3 mm, tumidity 1.3 mm.
Description.—Prodissoconch single stage evident only, oblong, truncated dorsally, flattened; sculpture with central irregular fine ridges, aligned parallel, occasionally connected by thin ridge segments, smooth at margins. Transition to dissoconch clear by change in sculpture. Length 200 μm. Dissoconch with straightened dorsal outline posteriorly; ventral, posterior and anterior margins convex; anterior most convex; shell rather flattened. Lunule and escutcheon absent. Sculpture irregularly spaced weak growth margins; some specimens nearly smooth. Margins sharp and smooth. Internal surface and margin smooth; muscle scars and pallial line inconspicuous. Hinge only known from right valve; wide hinge plates at 150°; posterior plate longer; nine anterior teeth, 13 posterior teeth (in right valve with length 3.3 mm), chevron-shaped in cross-section, central teeth in either row most pronounced. Triangular, oblique resilifer behind umbo.
Remarks.— Yoldiella retusa ( Hinds, 1843) is known from the Northern Indian Ocean ( Huber 2010) and is similar to Yoldiella umbostriata Hoffman & Little sp. nov. Hinds 1843: 99) reported the outline of this species as being nearly equilateral with a pointed anterior margin, and a length of
4.6 mm. Our shells are inequilateral with a more convex anterior and a maximum length of 3.3 mm.
Stratigraphic and geographic range.— Type locality and horizon only.
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