Malletiidae Adams & Adams 1858
- 1. Jackson School of Geosciences, University of Texas, Austin, TX 78712, USA; & Earth Sciences, Plymouth University, Plymouth, PL 4 8 AA, UK; & Department of Earth Sciences, Natural History Museum, London, SW 7 5 BD, UK;
- 2. Earth Sciences, Plymouth University, Plymouth, PL 4 8 AA, UK; & Department of Geology, University of Georgia, Athens, GA 30602, USA
- 3. Department of Earth Sciences, Natural History Museum, London, SW 7 5 BD, UK;
Description
Family Malletiidae Adams & Adams, 1858 gen. et sp. indet.
(Fig. 7)
Diagnosis. Subequilteral to inequilateral; usually with elongate, compressed posterior end; sculpture of commarginal striae or ribs; anterior and posterior gapes present; hinge plate weak, with fine taxodont teeth in two series, sometimes separated by plain area, without resilifer; ligament external, opisthodetic to amphidetic, weak; pallial sinus large.
Material. Three larval shells from LD-04 (NHMUK PI MB 1248–1250).
Description. Shell is equilateral, elliptical, H/L ratio of 0.7, and moderately inflated. Umbo is broad, orthogyrate, with beak positioned centrally. Shell smooth except for concentric growth lines. Hinge plate has three anterior and three posterior teeth in two series separated by a large plain area with a groove. Ligament is predominantly external, amphidetic and weak.
Remarks. Malletiidae are very similar to Nuculanidae, but the lack of a resilifer in mature adults supports their separation (Coan & Valentich-Scott 2012). These specimens do not belong to the Neilonellidae because they possess a small conspicuous gape between the valves. The Malletiidae is a long-ranging family known from the Ordovician to the Recent, and three genera (Malletia, Palaeoneilo and Taimyrodon) belonging to the family have previously been reported from the Lower Triassic (e.g. He et al. 2007; Wasmer et al. 2012). Externally, these specimens resemble the larval shells of Paleoneilo ? fortistriata figured by Wasmer et al. (2012), but they have far fewer hinge teeth. There are also equal numbers of anterior to posterior hinge teeth in these specimens, whereas in P. fortistriata there are many more posterior than anterior teeth (Wasmer et al. 2012).
Mode of life. Shallow infaunal, fully motile, slow, miner (Stanley 1968).
Notes
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Linked records
Additional details
Identifiers
Biodiversity
- Family
- Malletiidae
- Kingdom
- Animalia
- Order
- Nuculanida
- Phylum
- Mollusca
- Scientific name authorship
- Adams & Adams
- Taxon rank
- family
- Taxonomic concept label
- Malletiidae Adams, 1858 sec. Foster, Danise & Twitchett, 2017
References
- Adams, H. & Adams, A. 1858. The genera of recent Mollusca arranged according to their organization. John van Voorst, London, 661 pp.
- Coan, E. V. & Valentich-Scott, P. 2012. Bivalve seashells of tropical West America. Marine bivalve mollusks from Baja California to northern Peru. Santa Barbara Museum of Natural History Monographs 6, Santa Barbara, CA, 1258 pp.
- He, W., Feng, Q., Weldon, E. A., Gu, S., Meng, Y., Zhang, F. & Wu, S. 2007. A late Permian to Early Triassic bivalve fauna from the Dongpan section, southern Guangxi, South China. Journal of Paleontology, 81, 1009 - 1019.