The Echinoid Directory

Melonechinus Meek & Worthen, 1861, p. 396

[=Melonites Owen & Norwood, 1846, p. 225 (non Lamarck, 18122, p. 615); =Melechinus Quenstedt, 1875, p. 381 (objective); ?=Donbassechinus Faas, 1941, p. 73, type species]

Diagnostic Features	Test shape globular, typically large; plating thick and tesselate. Apical disc small; monocyclic; genital plates larger, pentagonal, with three gonopores to each plate. Ambulacra more or less straight and as wide as the interambulacral zones; multiserial throughout. An outer and and inner series of plates in each half ambulacrum with another 3 or 4 intermediate columns. Each plate with a small pore-pair; pore-pairs forming a rather broad band on either side of the ambulacrum. Innermost series of plates largest, with wide perradial zone. Only fine granulation; no primary tubercles. Interambulacral zones wide; composed of up to 9 regular columns of polygonal plates. Interambulacral plates with granulation only; no primary tubercle.. Peristome small, plating unknown. Lantern and spines unknown.
Distribution	Lower Carboniferous, USA, Europe, China, ?Former Soviet Union.
Name gender	masculine
Type	Melonites multipora Owen & Norwood, 1846, p. 225, by original designation.
Species Included	M. multiporus (Owen & Norwood, 1846); St Louis Group. Lower Carboniferous, USA. M. dispar (Fischer von Waldheim, 1848); Lower Carboniferous, Russia. M. parvus (Hambach, 1884); St Louis Group, Lower Carboniferous, USA. M. springeri Jackson, 1912; St Louis Group, Lower Carboniferous, USA M. crassus (Hambach, 1884); St Louis Group, Lower Carboniferous, USA. M. indianensis (Miller & Gurley, 1894); St Louis Group, Lower Carboniferous, USA. M. stewartii (Safford, 1869); St Louis Group, Lower Carboniferous, USA. M. septenarius (Jackson, 1896); Warsaw Group, Lower Carboniferous, USA. M. obovatus Jackson, 1912; Lower Carboniferous, USA. M. liratus jackson, 1912; Lower Carboniferous, USA. M. keepingi Jackson, 1912; Lower Carboniferous, England. M. etheridgei (Keeping, 1876); Lower Carboniferous, England. M. vanderbilti Jackson, 1912; Lower Carboniferous, USA. M. giganteus (Jackson, 1896); Lower Carboniferous, USA. M. chuseni Chao, 1942; Lower Carboniferous, China.
Classification and/or Status	Stem group Echinoidea; Palaechinidae. Assumed monophyletic.
Remarks	The wide adradial bands of pore-pairs, piercing small hexagonal columns of plates distinguishes this taxon from other Palaechinidae. Jackson, R. T. 1912. Phylogeny of the Echini, with a revision of Palaeozoic species Memoirs of the Boston Society of Natural History 7, 491 pp. 76 pls. Jackson, R. T. 1896. Studies of Palaeechinoida Geol. Soc. America Bull. 7, 171-254, pls 2-9.