Belongs within: Glyptocystitida.
The Callocystitidae are a group of Upper Ordovician to Upper Devonian cystoids distinguished from related groups by their particularly long ambulacra.
Callocystitids: ambulacra advancement and rhomb reduction
Published 10 January 2012
The Palaeozoic echinoderms included many distinctive groups that have no close relatives among the modern fauna: blastoids, cornutes, solutes, ctenocystoids… to name just a few. From the Ordovician to the Devonian, this diverse fauna also included a hodge-podge assemblage known as cystoids. Cystoids are a grouping of mostly stalked echinoderms in which certain plates in the theca are perforated by regular arrangements of pores that probably functioned in respiration. Cystoids were not always regularly pentamerous like other echinoderms, and some were notably asymmetrical. The ambulacra were recumbent on the theca, and the feeding appendages were brachioles rather than arms (for the difference between brachioles found in many fossil echinoderms and arms found in crinoids, see the post on blastoids). Cystoids would have been filter-feeders and were probably largely sedentary. Cystoids include some very disparate forms, and many researchers have suggested that they may represent a polyphyletic assemblage. Various authors have suggested cystoid ancestry for other echinoderm groups, such as blastoids or crinoids, but this remains controversial.
The Callocystitidae were a family of cystoids that persisted over most of the total cystoid time range. Callocystitids belonged to the major cystoid subgroup called the Rhombifera, in which the diagnostic pore groups were arranged as paired assemblies, commonly called pore rhombs, that spanned the border between two thecal plates (as opposed to the remaining cystoids, the Diploporita, in which pore assemblies each occupied a single plate). Broadhead & Strimple (1978) diagnosed the Callocystitidae based on the arrangement and position of the pore rhombs, together with their possession of a relatively small periproct (the circle of plates that indicates the position of the anus) and the number of radial plates in the theca. All callocystitids possessed a stalk, often divided into a flexible proximal section and a more rigid distal section. Broadhead & Strimple (1978) recognised four subfamilies of callosystitids, but one of these, the Apiocystitinae was explicitly suggested to be paraphyletic to the Callocystitinae and Staurocystinae. This was supported by the numerical phylogenetic analysis of Sumrall & Brett (2002), who furthermore suggested that the Callocystitinae was polyphyletic.
The fourth of Broadhead & Strimple’s subfamilies, the Scoliocystinae, was suggested to lie outside the clade formed by the other three; Sumrall & Brett’s analysis only included Scoliocystis, but does not contradict this. Scoliocystines have the ambulacra relatively short, restricted to the summit of the theca, and would have had only a small number of brachioles. The most extreme example was the Lower Silurian Osculocystis, which had only a single extremely long brachiole (Paul & Donovan 2011). Another scoliocystine, Schizocystis, had one side of the theca relatively flat and the pore rhombs reduced in number and restricted to the other side, and may have lain on its side in life rather than standing upright.
The remaining three subfamilies had more extensive ambulacra, extending right down to the base of the theca in some species. Apiocystitines and callocystitines had four or five ambulacra, usually branched in callocystitines and unbranched in apiocystitines, that did not strongly protrude above the surface of the theca and had widely spaced brachioles. The more distinctive Staurocystinae had two to four stongly protruding ambulacra that carried tightly packed brachioles. In the staurocystine Pseudocrinites, the theca was discus-shaped with its two ambulacra running around the outer rim of the disc (Kesling 1967).
Systematics of Callocystitidae
Characters (from Kesling 1967): Rhombiferan cystoids provided with distinct pectinirhombs; periproct relatively small, not produced; theca ovate, globular, biconvex, or ellipsoidal, not spindle-shaped or resembling a pentremite; rhombs relatively few, rarely developed as demirhombs; ambulacra long, extending down over theca; column present.
<==Callocystitidae [Apiocystinae, Apiocystitinae, Callocystidae, Callocystinae, Callocystitinae] |--Scoliocystinae [Scoliocystidae]SB02 | |--OsculocystisSB02 | |--GlansicystisSB02 | |--Schizocystis Jaekel 1895SB02, K67 [Schizocystinae] | | `--*S. armata (Forbes 1848) [=Echinoencrinus armatus]K67 | `--Scoliocystis Jaekel 1899SB02, K67 | |--*S. pumilus (Eichwald 1860) [=Caryocystites pumilus]K67 | `--S. thersitesK67 `--+--Lepadocystis Carpenter 1891SB02, K67 [=Meekocystis Jaekel 1899K67] | |--*L. moorei (Meek 1871) [=Lepocrinites moorei, Lepadocrinites (l. c.) moorei, *Meekocystis moorei]K67 | `--L. decorusSB02 `--+--+--Novacystis Paul & Bolton 1991SB02 | | `--*N. hawkesi Paul & Bolton 1991SB02 | `--StaurocystinaeK67 | |--Staurocystis Haeckel 1896K67 | | `--*S. quadrifasciata (Pearce 1843) [=Pseudocrinites quadrifasciatus]K67 | `--Pseudocrinites Pearce 1842SB02, K67 (see below for synonymy) | |--*P. bifasciatus Pearce 1842 (see below for synonymy)K67 | |--P. gordoni [incl. P. abnormalis]K67 | |--P. magnificusK67 | `--P. perdewi [incl. *Trimerocystis peculiaris Schuchert 1904]K67 `--+--Brockocystis Foerste 1914SB02, K67 | |--*B. tecumsethi (Billings 1866) [=Apiocystites tecumsethi]K67 | |--B. huronensisK67 | `--B. nodosariaK67 `--+--AnartiocystisSB02 | |--A. foersteiSB02 | `--A. whiteiSW07 `--+--Jaekelocystis Schuchert 1903SB02, K67 | |--*J. hartleyi Schuchert 1903K67 | |--J. avellanaK67 | `--J. papillataK67 |--Apiocystites Forbes 1848SB02, K67 [=Apiocystis Bather 1889K67] | |--*A. pentrematoides Forbes 1848 [=*Apiocystis pentrematoides]K67 | |--A. annaK67 | `--A. elegansK67 `--Callocystites Hall 1852SB02, K67 [=Callocystis Carpenter 1891K67; incl. Anthocystis Haeckel 1896K67] |--*C. jewetti Hall 1852 [=*Callocystis jewetti]K67 | |--C. j. jewettiK67 | `--C. j. elongatusK67 |--C. canadensisK67 `--‘*Anthocystis’ halliana Haeckel 1896K67 Callocystitidae incertae sedis: Coelocystis Schuchert 1903K67 `--*C. subglobosa (Hall 1867) (see below for synonymy)K67 Sphaerocystites Hall 1859 [=Sphaerocystis Carpenter 1891]K67 |--*S. multifasciatus Hall 1859 [=*Sphaerocystis multifasciatus]K67 `--S. globularisK67 Hallicystis Jaekel 1899K67 `--*H. imago (Hall 1864) [=Apiocystites imago]K67 Lipsanocystis Ehlers & Leighley 1922K67 `--*L. traversensis Ehlers & Leighley 192K67 Lovenicystis Regnéll 1945K67 `--*L. angelini (Jaekel 1899) [=Apiocystites angeli, Lepadocrinus angelini Haeckel 1896 (n. n.)]K67 Tetracystis Schuchert 1904K67 |--*T. fenestrata Schuchert 1904 [=Echinoencrinites fenestratus Troost 1849 (n. n.)]K67 `--T. chrysalisK67 Lepocrinites Conrad 1840 [=Lepadocrinites Billings 1854, Lepadocrinus Hall 1859, Lepocrinus Hall 1859]K67 |--*L. gebhardii Conrad 1840 [=*Lepadocrinites gebhardii, *Lepadocrinus gebhardii, *Lepocrinus gebhardii]K67 |--L. manliusK67 `--L. oblongusK67 Strobilocystites White 1876 [=Strobilocystis Carpenter 1891]K67 |--*S. calvini White 1876 [=*Strobilocystis calvini]K67 |--S. polleyiK67 `--S. schucherti Thomas 1924SG93
*Coelocystis subglobosa (Hall 1867) [=Hemicosmites subglobosus; incl. Sphaerocystis dolomiticus Jaekel 1899, Callocystites sphaeroidalis Foerste 1917]K67
Pseudocrinites Pearce 1842SB02, K67 [=Phacocystis Haeckel 1896K67, Pseudocrinus Haeckel 1896 non Geinitz 1846K67; incl. Trimerocystis Schuchert 1904K67]
*Pseudocrinites bifasciatus Pearce 1842 [=*Phacocystis bifasciata, *Pseudocrinus bifasciatus; incl. Pseudocrinites bicopuladigiti Garner 1844]K67
*Type species of generic name indicated
References
Broadhead, T. W., & H. L. Strimple. 1978. Systematics and distribution of the Callocystitidae (Echinodermata, Rhombifera). Journal of Paleontology 52 (1): 164–177.
[K67] Kesling, R. V. 1967. Cystoids. In: Moore, R. C. (ed.) Treatise on Invertebrate Paleontology pt S. Echinodermata 1. General characters. Homalozoa—Crinozoa (except Crinoidea) vol. 1 pp. S85–S267. The Geological Society of America, Inc., and The University of Kansas: Lawrence (Kansas).
Paul, C. R. C., & S. K. Donovan. 2011. A review of the British Silurian cystoids. Geological Journal 46: 434–450.
[SG93] Simms, M. J., A. S. Gale, P. Gilliland, E. P. F. Rose & G. D. Sevastopulo. 1993. Echinodermata. In: Benton, M. J. (ed.) The Fossil Record 2 pp. 491–528. Chapman & Hall: London.
[SB02] Sumrall, C. D., & C. E. Brett. 2002. A revision of Novacystis hawkesi Paul and Bolton 1991 (Middle Silurian: Glyptocystitida, Echinodermata) and the phylogeny of early callocystitids. Journal of Paleontology 76 (4): 733–740.
[SW07] Sumrall, C. D., & G. A. Wray. 2007. Ontogeny in the fossil record: diversification of body plans and the evolution of “aberrant” symmetry in Paleozoic echinoderms. Paleobiology 33 (1): 149–163.