Rhagasostoma Koschinsky 1885
Creators: name: Koromyslova, Anna V.
name: Taylor, Paul D.
name: Martha, Silviu O.
name: Riley, Matthew
Publisher: name: Zenodo
Year: 2018
Subjects: Biodiversity
Taxonomy
Animalia
Bryozoa
Gymnolaemata
Cheilostomatida
Onychocellidae
Rhagasostoma

description: Key to species of Rhagasostoma described in this paper
1. Avicularia interzooidal, peripheral caverns usually present ............................................................. 2
– Avicularia vicarious, ovicells immersed, peripheral caverns lacking ............................................... 3
2. Avicularia longer than autozooids, ovicells endozooidal or immersed ............................................ 4
– Avicularia about ½ the autozooid size or less, ovicells endozooidal ................................................ 5
3. Opesia of autozooids with opesiular indentations ..................................... R. rowei (Brydone, 1906)
– Opesia of autozooids with opesiules ...................................................... R. mimosa (Brydone, 1930)
4. Avicularian rostrum conical in outline, ovicells endozooidal ........................................................... 6
– Avicularian rostrum spade-shaped, ovicells immersed or not observed ........................................... 7
– Avicularian rostrum falciform, ovicells endozooidal ....................................................................... 8
5. Avicularian rostrum short and tilted to the right or left, gymnocyst present .................................... 9
– Avicularian rostrum long and straight, gymnocyst lacking ............ R. tchvanovi (Favorskaya, 1992)
6. Avicularian rostrum asymmetrical .................................................................................................. 10
– Avicularian rostrum symmetrical .....................................................................................................11
7. Avicularian rostrum narrowed at the base, enlarged centrally and ended with top, ovicells immersed ............................................................................................................. R. brydonei sp. nov.
– Avicularian rostrum almost the same width along the whole of its length and with pointed or rounded top, ovicells not observed ............................................................................. R. operculatum sp. nov.
8. Avicularian rostrum with one side of rostrum almost straight and other side curved near top .......... .................................................................................................................. R. minuens Brydone, 1936
9. Autozooidal cryptocyst with slightly convex border; gymnocyst very rarely observed .................... ............................................................................................................. R. gibbosum (Marsson, 1887)
– Autozooidal cryptocyst with convex border; gymnocyst well developed .......................................... ............................................................................................................. R. gibbosulum Brydone, 1936
10. Avicularian opesia large, roundish or oval with thickened distolateral edge and with thin articular ridges bearing two short teeth proximally and a short or long, slit-like opesiular indentation between the teeth; opesiules lacking ................................................................. R. inelegans (Lonsdale, 1850)
– Avicularian opesia distal, small, subcircular; two lateral parallel slit-like opesiules formed by long teeth of articular ridges and a long, slit-like opesiular indentation between the teeth proximally below opesia .............................................................................................. R. angliae Brydone, 1936
11. Avicularian opesia egg-shaped, with thin articular ridges bearing two short teeth proximally and a short or long slit-like opesiular indentation between the teeth; opesiules lacking ............................. ............................................................................................................................. R. aralense sp. nov.
description: Published as part of Koromyslova, Anna V., Taylor, Paul D., Martha, Silviu O. & Riley, Matthew, 2018, Rhagasostoma (Bryozoa) from the Late Cretaceous of Eurasia: taxonomic revision, stratigraphy and palaeobiogeography, pp. 1-66 in European Journal of Taxonomy 490 on pages 56-57, DOI: 10.5852/ejt.2018.490, http://zenodo.org/record/3830845