Melanella indicaformis DeVries 2019, sp. nov.
Creators
Description
Melanella indicaformis sp. nov. (Figure 4 (h – l))
Diagnosis
Shell small, elongate. Whorls smooth, flat-sided. Aperture oval, elongate, without anterior or posterior canals. Columella smooth, umbilicus absent.
Description
Shell length less than 15 mm, elongate, spire angle about 15°. Protoconch conical, about two smooth whorls. Teleoconch with about five whorls; whorls smooth, glossy, flat-sided to slightly convex, sometimes weakly turreted, thick; spire sometimes bent. Sutures adpressed; short crimped sutural collar sometimes overlaps preceding whorl. No spiral or axial sculpture. Base smooth, evenly rounded, set apart from rest of whorl by weak or moderately strong angulation. Aperture oval, twice as long as wide. Parietal callus strong; columellar callus thin; basal lip thickened, continuous with base of columella. Outer lip moderately thick, without teeth. Umbilicus absent.
Remarks
Species of Melanella have been reported from Paleocene rocks in New Zealand (Finlay and Marwick 1937) and Antarctica (Stillwell et al. 2004) and Eocene and Oligocene strata from North America (MacNeil and Dockery 1984; Garvie 1996) and New Zealand (Maxwell 1992).
A species similar to Melanella indicaformis was provisionally assigned to Pseudomelania by Olsson (1944): P. simplex Olsson, 1944, found in upper Campanian beds of the Tortuga Formation in the Sechura Basin of northern Peru. The Tortuga Formation species is longer than the Caballas Formation species (length 18 mm vs 12 mm) and has nearly microscopic spiral threads, but the convexity of the spire, the glossy surface, and thickened inner lip are shared characters. A late Eocene species with a similar form, Bayania epelys Woodring, 1973 from the Canal Zone of Panama, differs from the Caballas Formation Melanella indicaformis by having faint spiral sculpture on the last whorl and a very shallow recurved siphonal notch. An early Oligocene species from the Talara Basin of northern Peru, Pachychilus canoaensis Olsson, 1931, from the estuarine and freshwater Bravo Grits of the Mancora Formation, also resembles M. indicaformis and may be referable to Melanella.
Modern species of Eulimidae, including Melanella, are noted for their parasitism of echinoderms (Warén 1983). Echinoderms are noted for their intolerance of brackish conditions, although some extant brackish-water echinoderms do exist (Turner and Meyer 1980). No echinoderms have been encountered in beds of the Cuenca Member, despite an abundance of Melanella shells.
Etymology
‘ Indica ’, referencing the long-grained variety of rice that this species resembles.
Material
UWBM 107617, holotype, B8769 (type locality), L 11.1, W 4.1; remainder are paratypes: UWBM 107618, B8772, L 10.6, W 4.1; UWBM 107619, B8769, L 9.4, W 3.6; UWBM 107620, B8772, L 8.2, W 3.1; UWBM 107621, B8772, L 8.7, W 3.2; UWBM 107622, B8769, L (8.4), W (4.7); UWBM 107623, B8769, L 8.2, W 3.3; UWBM 107624, B8772, L 6.0, W 2.8; UWBM 107625, B8772, L 5.0, W 2.6; UWBM 107626, B8770, L 4.5, W 2.4; MUSM INV 266, B8772, L 8.4, W 3.3; MUSM INV 267, B8769, L (9.0), W 3.4; MUSM INV 268, B8772, L 6.1, W 2.6
.
Occurrence
Lower Paleogene, Cuenca Member, Caballas Formation, East Pisco Basin, southern Peru.
Notes
Files
Files
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System files
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Linked records
Additional details
Identifiers
Biodiversity
- Collection code
- MUSM , UWBM
- Family
- Eulimidae
- Genus
- Melanella
- Kingdom
- Animalia
- Material sample ID
- INV 266 , INV 267 , INV 268 , UWBM 107617 , UWBM 107618 , UWBM 107619 , UWBM 107620 , UWBM 107621 , UWBM 107622 , UWBM 107623 , UWBM 107624 , UWBM 107625 , UWBM 107626
- Order
- Littorinimorpha
- Phylum
- Mollusca
- Scientific name authorship
- DeVries
- Species
- indicaformis
- Taxonomic status
- sp. nov.
- Taxon rank
- species
- Type status
- holotype , paratype
- Taxonomic concept label
- Melanella indicaformis DeVries, 2019
References
- Finlay HJi Marwick J. 1937. The Wangaloan and associated molluscan faunas of Kaitangata - green Island Subdivision. New Zealand Geol Survey Paleontological Bull. 15: 1 - 140.
- Stillwell JDi Zinsmeister WJi Olenik AE. 2004. Early Paleocene mollusks of Antarctica: systematicsi paleoecology and paleobiogeographic significance. Bulletins Am Paleontol. 367: 1 - 89.
- MacNeil FSi Dockery DT III. 1984. Lower Oligocene Gastropodai Scaphopodai and Cephalopoda of the Vicksburg Group in Mississippi. Mississippi Dept Nat Resour Bur Geol Bull. 124: 1 - 415.
- Garvie CL. 1996. The molluscan macrofauna of the Reklaw Formationi Marquez Member (Eocene: Lower Claibornian) i in Texas. Bulletins Am Paleontol. 111 (352): 1 - 177.
- Maxwell PA. 1992. Eocene Mollusca from the vicinity of McCulloch ' s Bridgei Waihao Riveri South Canterburyi New Zealand: Paleoecology and systematics. New Zealand Geol Survey Paleontological Bull. 65: 1 - 280.
- Olsson AA. 1944. Contributions to the Tertiary paleontology of northern Peru. Part VII. The Cretaceous of the Paita region. Bulletins Am Paleontol. 19 (68): 1 - 147.
- Waren A. 1983. A generic revision of the family Eulimidae (Gastropodai Prosobranchia). J Molluscan Stud Suppl. 13: 1 - 96.
- Turner RLi Meyer CE. 1980. Salinity tolerance of the brackish-water echinoderm Ophiophragmus filograneus (Ophiuroidea). Mar Ecol Progr Ser. 2: 249 - 256.