Phrynocrinidae

Messing, Charles G., 2016, Porphyrocrinus daniellalevyae n. sp. (Echinodermata: Crinoidea), a sea lily from the tropical western Atlantic with a unique crown pattern, Zootaxa 4147 (1), pp. 1-35 : 2-3

publication ID

https://doi.org/10.11646/zootaxa.4147.1.1

publication LSID

lsid:zoobank.org:pub:DFDC5EE6-BB16-4BDD-883D-3530AAD04FA0

DOI

https://doi.org/10.5281/zenodo.6069862

persistent identifier

https://treatment.plazi.org/id/03A6C633-C848-4504-CAE9-FD1B71A4FF42

treatment provided by

Plazi

scientific name

Phrynocrinidae
status

 

Family Phrynocrinidae AH Clark, 1907a

Emended diagnosis. Aboral cup with visible sutures between ossicles; radials and basals easily separated; radials usually taller than basals; rays either undivided or branched following a primibrachial series of more than two ossicles; ligamentary articulations joining primibrachs 1–2 (IBr1+2) and more distal brachials at variable intervals; first pinnule on brachial 5 to 10, more frequently 7–8; proximale absent; stalk xenomorphic, with mesistele and dististele columnals mostly articulated by synarthries having deep ligamentary depressions; attachment via irregular encrusting disk.

Remarks. Phrynocrinidae has previously been subdivided with varying membership, e.g., AM Clark (1973) placed Porphyrocrinus Gislén, 1925 , and Naumachocrinus AH Clark, 1912, in a separate Porphyrocrinidae , whereas Hess (2011) followed Mironov (2000) in recognizing monogeneric Phrynocrininae and Porphyrocrininae within Phrynocrinidae . DNA sequence data support Phrynocrinidae as monophyletic ( Hemery 2011; Hemery et al. 2013) with two genera and no subfamilial distinctions. Phrynocrinus A.H. Clark, 1907a , includes only P. nudus A.H. Clark, 1907a , known from the W Pacific ( Donovan & Pawson 1994; Améziane & Roux 2001; Tunnicliffe et al., 2015). Porphyrocrinus currently includes four extant taxa and one fossil species (see below).

Hemery (2011) returned three terminals treated as Porphyrocrinus n. sp. (but representing 1–2 species) as sister to one Phrynocrinus n. sp. Hemery et al. (2013) returned Porphyrocrinus thalassae Roux, 1977 , and Por. cf. verrucosus Gislén, 1925 , as sister to Phrynocrinus nudus . Both reconstructions returned Phrynocrinidae as sister to a clade composed of Bathycrinidae , Bourgueticrinidae (both stalked), and Atelecrinidae (feather stars).

External morphology placed the family with Bourgueticrinidae , Bathycrinidae and Septocrinidae in suborder Bourgueticrinina within order Comatulida (Hess 2011) . However, recent molecular data indicate that Bourgueticrinina is polyphyletic. Cohen et al. (2004), Rouse et al. (2013) and Hemery et al. (2013) all produced trees in which the bathycrinid-like Caledonicrinus Avocat & Roux, 1990 (in Améziane-Cominardi et al. 1990) , branched well away from other included bourgueticrinines, supporting Mironov’s (2000) removal of this genus to a separate Caledonicrinidae Mironov, 2000. Rouse et al. (2013) recommended reducing Bourgueticrinina to family Bourgueticrinidae , including within it at least Bathycrinus Thomson, 1872 ( Bathycrinidae ), Democrinus Perrier, 1883 ( Bourgueticrinidae ), Porphyrocrinus and Phrynocrinus . However, Hemery et al. ’s (2013) tree returned seven bourgueticrinines (except Caledonicrinus ) as a paraphyletic clade with the feather star family Atelecrinidae (not included in Rouse et al. 2013) nested within as sister to Bathycrinidae . Knobby processes on the interior surface of primibrachial ossicles in Bathycrinidae ( Bathycrinus , Cingocrinus , Discolocrinus , Monachocrinus ) and Bourgueticrinidae ( Democrinus ) (Carpenter 1884a, pl. VII, 4a; Macurda and Meyer 1976, pl. 3.5; Mironov 2008; Mironov and Pawson 2014) correspond with those in Atelecrinidae (Messing, 2004, 2013), but do not occur in Septocrinidae , Caledonicrinidae or Phrynocrinidae . These features reflect molecular reconstructions that placed Phrynocrinidae sister to a Bourgueticrinidae +( Bathycrinidae + Atelecrinidae ) clade ( Hemery et al. 2013; Rouse et al. 2013), and returned both Septocrinidae (represented by Rouxicrinus vestitus —misidentified as Monachocrinus caribbeus in Rouse et al. (2013) —see Mironov and Pawson (2010, 2014)) and Caledonicrinidae as distant branches. Phrynocrinidae is maintained here based on the absence of knobby processes, and strong bootstrap (100%) and posterior probability (1) supports in the phylogenetic tree ( Hemery et al. 2013) distinguishing it from its bathycrinid/bourgueticrinid/atelecrinid sister clade.

Finally, AM Clark (1973) diagnosed Porphyrocrinidae (followed by Hess (2011) for Porphyrocrininae ) as having arms undivided. However, Porphyrocrinus thalassae usually has 8–15 arms; a single ray may divide once or twice (Roux 1977, 1985).