Kionaster petersonae, n. gen. and sp. (Asteroidea), the first fossil occurrence of the Asterodiscididae, from the Miocene of Florida

Abstract

Kionaster petersonae, n. gen. and sp., from the Miocene Chipola Formation of Florida, is the first-known fossil member of the extant family Asterodiscididae Rowe. Although abactinal and marginal expressions clearly serve to distinguish the Asterodiscididae, the family was recognized only relatively recently, in part perhaps because assigned genera are few and these occur in traditionally less heavily collected areas. The original inferred presence of reduced numbers of marginal ossicles in the family is rejected. Phylogenetic analysis suggests close affinities between asterodiscidids and Goniaster L. Agassiz, 1836 (Goniasteridae). Kionaster appears closest to the eastern Pacific asterodiscidids rather than Asterodiscides itself, which is widely distributed farther west in the Pacific. Distinctive characters of Kionaster suggest a once-greater diversity within the family. Although data are limited, morphologic similarities and biogeographic distributions suggest familial origin in a low-latitude Western Hemisphere setting and the Atlantic Ocean prior to the closing of the Isthmus of Panama.

<p><strong>Comments on "The phylogeny of post-Palaeozoic Asteroidea </strong><strong>(Neoasteroidea, Echinodermata)" by A.S. Gale and perspectives </strong><strong>on the systematics of the Asteroidea</strong></p>

“…Survey of all available specimens in many museums in the United States, Europe, and Australia led to a series of publications exploring affinities of taxa (Blake 1972;1978;1979;1980;1981b;; museum survey syntheses, not assumptions of monophyly, formed the basis of Blake (1987). That the publication series of Blake remains incomplete, however, is implicit in treatment of Goniaster Agassiz in Blake and Portell (2011). Even if the misinterpretations of Gale (2011a) on an assumption of monophyly by Blake (1987) were correct, it would not validate following this approach in his own work.…”

The first complete mitochondrial genome of the Northern Pacific deep-sea goniasterid sea star Ceramaster japonicus (Sladen, 1889) determined using NGS-based shotgun sequencing

“…The Goniasteridae is the most diverse group within the Asteroidea, and has demonstrated important relationships with other members of the Valvatida, such as the Asterodiscididae, the Oreasteridae, and the Ophidiasteridae (e.g. Blake and Portell 2011 ; Mah 2017 ).…”

Asteroid (Echinodermata) skeletal elements from upper Oligocene deposits of Jamaica and Antigua

“…Terminology of the asteroid endoskeleton follows Spencer & Wright (1966) and Blake & Portell (2011). Jamaican stratigraphic nomenclature is adapted from Mitchell (2004); that of Antigua follows Weiss (1994) and references therein.…”

“…In other taxa, extended spine-like processes are found on only some ossicles (e.g. the arthrodiscidid valvatidan Kionaster Blake & Portell, 2011). Further, marginal ossicles are only one of a number of ossicular types in asteroids, all showing their own ranges of variation.…”