Gastropoda

Eucithara

Belongs within: Mangeliidae. Dazed and Cythara Published 19 August 2026 I’ve had occasion multiple times on this site to comment on the taxonomic complications surrounding the conoid gastropods, ‘turrids’ in the broad sense. Nevertheless, among the more complicated cases is that of the genus name Cythara. Cythara striata was established by Christian Schumacher in 1817 for a… Continue reading Eucithara

Scoliostomatidae

Belongs within: Gastropoda. The Scoliostomatidae are a Devonian family of gastropods with a distinctive shell morphology: at maturity, the last whorl of the shell twists outwards and backwards, so its apparent position is reversed relative to the rest of the shell. This gerontic whorl also turns upwards in members of the subfamily Scoliostomatinae but not… Continue reading Scoliostomatidae

Belongs within: Mollusca.Contains: Scoliostomatidae, Caseolus, Leiostyla, Clisospiroidea, Bellerophontoidea, Archinacelloidea, Pelagielloidea, Macluritida, Neomphaliones, Patellogastropoda, Vetigastropoda, Neritimorpha, Loxonematoidea, Heterobranchia, Peruneloidea, Cyclophoroidea, Ampullariidae, Viviparoidea, Orthonematoidea, Subulitoidea, Soleniscidae, Meekospiridae, Cerithiimorpha, Hypsogastropoda. The Gastropoda, snails and slugs, are a major clade of molluscs characterised by the process of torsion during larval development with the visceral mass and mantle becoming turned… Continue reading Gastropoda

Archinacelloidea

Belongs within: Gastropoda. The Archinacelloidea are an Ordovician to Silurian group of low, spoon-shaped shells with the apex anterior and just overhanging the margin of the aperture. <==Archinacelloidea [Archinacellacea]GS75 |–Archaeopraga Horný 1963 [Archaeopragidae]BR05 | `–*A. pinnaeformis (Perner 1903) [=Helcionopsis pinnaeformis]BR17 `–ArchinacellidaeBR05 |–BarrandicellaBR05 |–Archinacellopsis patelliformisGS75 |–Floripatella rousseaui Yochelson 1988TTE93 |–Guelphinacella canadense (Whiteaves 1884)TTE93 `–Archinacella Ulrich & Scofield… Continue reading Archinacelloidea

Pterothecidae

Belongs within: Bellerophontoidea. The Pterothecidae are an Ordovician to Devonian group of bellerophontoids with a rapidly expanding shell bearing a more or less developed plate at the aperture, and a selenizone on a dorsal crest (Knight et al. 1960). PterothecidaeBR05 |–Pedasiola Spriesterbach 1919 [Pedasiolinae]BR05 | `–*P. rhenana Spriestersbach 1919KC60 |–PterothecinaeBR05 | |–Cyclotheca Teichert 1935 non Theiss. 1914 (ICBN)KC60… Continue reading Pterothecidae

Bellerophontoidea

Belongs within: Gastropoda.Contains: Euphemitinae, Tropidodiscidae, Pterothecidae, Knightitinae, Bellerophontinae, Bucaniinae, Sinuitidae. The Bellerophontoidea are a lineage of coiled molluscs known from the Upper Cambrian to the Lower Triassic. The shell is isostrophic, superficially similar to a small nautiloid, with a median emargination or tremata (Knight et al. 1960). The bellerophontoids have most commonly been presumed to… Continue reading Bellerophontoidea

Sinuitidae

Belongs within: Bellerophontoidea. The Sinuitidae are a group of involute to partly evolute planispiral bellerophontoids with a posterior apertural sinus or broad slit, known from the early Late Cambrian to the Early Triassic (Runnegar & Jell 1976). Sinuitidae [Sinuitoidea]BR05 | i. s.: Cloudia Knight 1947RJ76 | `–*C. buttsi Knight 1947KC60 | Gamadiscus Horny 1962RJ76 | Strepsodiscus… Continue reading Sinuitidae

Scutellastra

Belongs within: Patellogastropoda. Scutellastra is a genus of limpets bearing rather massive shells with an opaque, non-iridescent porcellaneous interior, and having the median central radular tooth well developed (Wilson 1993). <==Scutellastra Adams & Adams 1854 [incl. Patellanax Iredale 1924, Penepatella Iredale 1929]W93 | i. s.: S. soyaensis (Kase & Shigeta 1996) [=Patella soyaensis]NO04 |–+–S. mexicana (Broderip &… Continue reading Scutellastra

Macluritida

Belongs within: Gastropoda.Contains: Trochonematidae, Lophospiridae, Euomphalidae, Raphistomatidae, Helicotomidae, Omphalotrochidae, Platyschismatinae, Turbonellininae. The Macluritida are a group of gastropods known from the Upper Cambrian to the Triassic, possessing a hyperstrophic to depressed-orthostrophic shell (Knight et al. 1960). The shell often bears an angulation on the outer surface of the whorl that is presumed to mark the… Continue reading Macluritida

Lottia

Belongs within: Lottiidae. Lottia is a genus of large, low limpets with a nearly marginal apex and muscle impressions joined by a curved line, found in the North Pacific and North Atlantic (Knight et al. 1960; Nakano & Ozawa 2004). Lottia Gray 1833BR05 (see below for synonymy) | i. s.: L. alveusCG99 | L. conica [incl. Scurria pallida]C64 |… Continue reading Lottia