The cushion–star Parvulastra exigua in South Africa : one species or more?
Date
2015-09
Journal Title
Journal ISSN
Volume Title
Publisher
Pensoft
Abstract
The cushion–star Parvulastra exigua (Lamarck, 1816) is a widely distributed member of the temperate
intertidal fauna in the southern hemisphere. In South Africa, it occurs in sympatry with the endemic
Parvulastra dyscrita (Clark, 1923), the two species being differentiated predominantly by gonopore placement.
Several recent studies have suggested that there may be additional cryptic species within the P. exigua
complex in South Africa, based variously on color morphology, genetic evidence and the differential
placement of the gonopores. This paper attempts to resolve whether one or more species are represented
within P. exigua. A total of 346 P. exigua and 8 P. dyscrita were collected from sites on the west and south–
west coasts of South Africa; morphological, anatomical and genetic analyses were performed to determine
whether cryptic species and/or P. exigua specimens with aboral gonopores were present. Results show that
neither cryptic species nor P. exigua specimens with aboral gonopores occur at these sites. This study thus
refutes previous claims of the existence of aboral gonopores in South African P. exigua, and suggests that
a single species is represented. The distinction between P. exigua and P. dyscrita is also confirmed, and
features separating these two species are clarified and documented.
Description
CITATION: Payne, R. P. et al. 2015. The cushion–star Parvulastra exigua in South Africa : one species or more? ZooKeys, 524:1–16, doi: 10.3897/zookeys.524.6145.
The original publication is available at http://zookeys.pensoft.net
The original publication is available at http://zookeys.pensoft.net
Keywords
Cryptic species, Gonopore, Parvulastra dyscrita, Parvulastra exigua, Patiriella, Starfish
Citation
Payne, R. P. et al. 2015. The cushion–star Parvulastra exigua in South Africa : one species or more? ZooKeys, 524:1–16, doi: 10.3897/zookeys.524.6145.