Revision of Cyclida (Pancrustacea, Multicrustacea), with five new genera

Abstract

All cyclidan species represented by existing material are illustrated photographically. New genera within Cyclidae include Ambocyclus new genus; Carabicyclus new genus; Chernyshevine new genus, Litocyclus new genus; and Tazawacyclus new genus with the following new combinations: A. capidulum (Chernyschev, 1933); A. simulans (Reed, 1908); A. ? minutus (Rogers, 1902); Carabicyclus wrighti (Woodward, 1870); L. bilobatus (Woodward, 1870); L. ? communis (Rogers, 1902); L. jonesianus (Woodward, 1870); L. ? permarginatus (Rogers, 1902); L. torosus (Woodward, 1870); Chernyshevine spinosus (Chernyschev, 1933); T. tazawai (Niko & Ibaraki, 2011); U. harknessi (Woodward, 1870); and U. woodwardi (Reed, 1893). New genera within Americlidae include Brittaniclus and Dziklus with the following new combinations: B. rankini (Woodward, 1868); B. scotti (Woodward, 1894); B. testudo (Peach, 1882); and D. obesus (Schram, Vonk & Hof, 1997). A neotype is herein designated for Halicyne plana. Each family within Cyclida occupies a distinct morphospace. Two families survived the end-Permian mass extinction event. Most cyclidans occupied marine conditions, but some are known from marginal marine and freshwater environments.

Malayacyclusgen. nov., the first Southeast Asian Cyclida (Crustacea) from the Early Carboniferous of Terengganu, Malaysia

“…No cyclidan occurrence is yet confirmed in the Mississippian of North America: this is a puzzle. Its earliest appearance in North America is known to be the Bashkirian Schramine montanaensis (Schram, Boere, & Thomas, 2006) of the long-ranging family Schraminidae (see Schweitzer et al, 2020).…”

“…The fossil specimens are registered with numbers prefixed UMF and are deposited in the Department of Geology, University of Malaya, Kuala Lumpur. Here, the morphological terminology and systematic classification follow Feldmann and Schweitzer (2019) and Schweitzer et al (2020), respectively.…”

“…Included genera . Americlus Dzik, 2008; Brittaniclus Schweitzer et al, 2020; Dziklus Schweitzer et al, 2020.…”

“…During the early establishment of cyclidan taxonomy, most species were placed in Cyclus de Koninck, 1841, and some in Halicyne von Meyer, 1847. In the latest revisions of the order Cyclida (see Feldmann & Schweitzer, 2019; Mychko & Alekseev, 2018; Schweitzer, Mychko, & Feldmann, 2020), a total of 26 genera and 52 species were reviewed and grouped into six families.…”

“…Data compiled from Schweitzer et al (2020), plus a new Early Carboniferous species of the Americlidae in this report F I G U R E 7 Early Carboniferous distributions of the Cyclidae and Americlidae plotted on the global palaeogeographical reconstruction map (modified after the Visean map of Qiao & Shen, 2014, fig.3). Numbers inside each family's symbol represent the number of species that occurred in each palaeogeographical region (information fromSchweitzer et al, 2020). Cyclus radialis was reported also from Belgium, besides the British Isles (seeSchweitzer et al, 2020), and both occurrences are included in this figure (1* for the Belgian cyclid occurrence).…”