Aspidytidae is a family of aquatic beetles of the suborder

Adephaga The Adephaga (from Greek ἀδηφάγος, ''adephagos'', "gluttonous") are a suborder of beetles, and with more than 40,000 recorded species in 10 families, the second-largest of the four beetle suborders. Members of this suborder are collect ...

, described in 2002 from specimens in

South Africa South Africa, officially the Republic of South Africa (RSA), is the southernmost country in Africa. It is bounded to the south by of coastline that stretch along the South Atlantic and Indian Oceans; to the north by the neighbouring coun ...

and

China China, officially the People's Republic of China (PRC), is a country in East Asia. It is the world's List of countries and dependencies by population, most populous country, with a Population of China, population exceeding 1.4 billion, slig ...

. There are only two known species in the family and these were originally described in the genus '' Aspidytes,''Beutel, R.G., Balke, M. & Ribera, I. (2016) 7.7. Aspidytidae Ribera,Beutel, Balke and Vogler, 2002. In: Beutel, R.G. & Leschen, R.A.B. (eds.): ''"Handbook of Zoology, Arthropoda: Insecta. Coleoptera, Beetles. Vol. 1: Morphology and Systematics"'' (Archostemata, Adephaga, Myxophaga, Polyphaga partim). 2nd Edition. Walter de Gruyter, Berlin. pp. 141-149. but later the new genus '' Sinaspidytes'' was erected for the species found in China''.'' The family can also be referred to by its trivial name cliff water beetles.

Description

Cliff water beetles have a streamlined body that is dorsally convex. Their size ranges from 4.8 - 7.0 mm in length.

Dorsal side Standard anatomical terms of location are used to unambiguously describe the anatomy of animals, including humans. The terms, typically derived from Latin or Greek roots, describe something in its standard anatomical position. This position ...

is predominantly black and cuticle is shiny. The head is laterally rounded and shortened with the

compound eyes A compound eye is a visual organ found in arthropods such as insects and crustaceans. It may consist of thousands of ommatidia, which are tiny independent photoreception units that consist of a cornea, lens, and photoreceptor cells which distin ...

integrated in the outline. Legs lack swimming hairs.

Known species of Aspidytidae

'' Aspidytes niobe -'' known from

. Body length 6.5 - 7.2 mm '' Sinaspidytes wrasei -'' has only been found at one location in the Shaanxi province, China. Body length 4.8 – 5.2 mm.

Biology and ecology

Larvae and adults of both ''A. niobe'' and ''S. wrasei'' are found in or in close proximity of hygropetric habitats - meaning they require a rock surface covered by a thin layer of water. Both adults and larvae are likely predacious. Eggs and pupa are yet unknown.

Phylogeny and evolution

The phylogenetic placement of Aspidytidae within the superfamily Dytiscoidea is still under debate, and even whether the family is monophyletic or paraphyletic with respect to Amphizoidae. Initially both species were categorized in the same genus – ''Aspidytes''. Later ''Sinaspidytes'' was erected for ''S. wrasei'' following a phylogenetic analysis using 11 genes that recovered Aspidytidae as praphyletic. Later studies using genomic data have been inconclusive. A study using ultraconserved elements (UCE) still recovered Aspidytidae as paraphyletic, but with a different arrangement between the two species and Amphizoidae. However, two of the latest studies using genomic data do recover a monophyletic Aspidytidae.

References

{{Taxonbar, from=Q778888 Adephaga Beetle families