Annulariidae


The family Annulariidae is a taxonomic family of small operculate land snails in the superfamily Littorinoidea.

Characteristics

This family encompasses all New World "Cyclostomoid" mollusks previously classified under the family names Cyclostomatidae or Eriidae.
Key Distinguishing Characteristics:
The primary feature that separates this family from all other operculate pulmonates is found in the radula, which exhibits a fundamental uniformity across the large number of included species.
;Radula Structure : the radula possesses a consistent tooth arrangement:
  • Rachidian tooth: single and unicuspid.
  • Lateral tooth: single and unicuspid.
  • Inner marginal tooth: resembles the lateral tooth in form but is multicuspid.
  • Outer Mmrginal tooth: long and curved like a bow. It is pectinated on both its recurved edge and its main portion, but these pectinations do not divide it into individual teeth.
  • Jaw: absent.
; Foot and progression: The sole of the foot is longitudinally divided by a sulcus, which separates it into two muscular masses. These two masses function independently, allowing the animal a method of progression by alternate waves of muscular contraction. The foot is relatively short.
; Head and sensory organs
  • Muzzle: a bifid muzzle of varying length is always present.
  • Tentacles: they are long, slender, and either fibrillar or slightly swollen at the ends.
  • Eyes: The eyes are situated at the base of the tentacles on the outer side. They are often raised above the surface of the head by a fleshy protuberance.
; Operculum: The operculum displays a wide degree of variation across the family's divisions, yet it follows distinct evolutionary lines of progression. The structure ranges from a simple type to a highly complicated one, with intermediate steps easily traceable. All opercula possess a basal chondroid plate upon which calcareous ribs and lamellae are deposited. Modifications of these calcareous structures are used to subdivide the family into a series of subfamilies and genera, as will be discussed below.
; Shell: The shell shape varies widely, from depressed helicoid to elongate conic. The surface sculpture varies greatly: from axially ribbed only to axially ribbed and spirally lirate. The intensity of these elements ranges from obsolete to lamellose.

Genera

;Subfamily Abbottellinae Watters, 2016Abbottella Henderson & Bartsch, 1920Abbottipoma Watters, M. L. Smith & Sneddon, 2020Annularisca Henderson & Bartsch, 1920Arenabbottella Watters, M. L. Smith & Sneddon, 2020Lagopoma Bartsch, 1946Leiabbottella Watters, 2010Meganipha F. G. Thompson, 1978Microabbottella Watters, M. L. Smith & Sneddon, 2020Opisthosiphon Dall, 1905Preclaripoma Watters, M. L. Smith & Sneddon, 2020Rolleia Crosse, 1891
;Subfamily Annulariinae Henderson & Bartsch, 1920Adamsiella L. Pfeiffer, 1851Annularia Schumacher, 1817Annularops Henderson & Bartsch, 1920Blaesospira Crosse, 1891Chittypoma Watters, 2006Cistulops H. B. Baker, 1924Eyerdamia Bartsch, 1946Juannularia de la Torre & Bartsch, 1941Lugarenia de la Torre & Bartsch, 1941Megannularia Watters, 2006Saulaepoma Watters, 2006Weinlandipoma Bartsch, 1946Xenopoma Crosse, 1891Xenopomoides de la Torre & Bartsch, 1941
;Subfamily Chondropomatinae Henderson & Bartsch, 1920Aguayotudora de la Torre & Bartsch, 1941Annularodes Henderson & Bartsch, 1920Bonairea H. B. Baker, 1924Chondropoma L. Pfeiffer, 1847Chondrops Bartsch, 1946Chondrothyrium Henderson & Bartsch, 1920Colonella Bartsch, 1946Crossepoma Bartsch, 1946Cubadamsiella de la Torre & Bartsch, 1941Diplopoma L. Pfeiffer, 1859Parachondria Dall, 1905Parachondrops Henderson & Bartsch, 1920Rhytidopoma Sykes, 1901Rhytidothyra Henderson & Bartsch, 1920
;Subfamily Rhytidopomatinae Henderson & Bartsch, 1920Colonina Bartsch, 1946Ramsdenia Preston, 1913
;Subfamily Tudorinae Watters, 2006Annularita Henderson & Bartsch, 1920Articulipoma Bartsch, 1946Choanopomops H. B. Baker, 1928Chondropomartes Henderson & Bartsch, 1920Chondropomella Bartsch, 1932Chondropometes Henderson & Bartsch, 1920Chondropomium Henderson & Bartsch, 1920Chondrothyra Henderson & Bartsch, 1920Clydonopoma Pilsbry, 1933Colobostylus Crosse & P. Fischer, 1888Dallsiphona de la Torre & Bartsch, 1941Eutudora Henderson & Bartsch, 1920Gouldipoma Watters, 2006Gutierrezium de la Torre & Bartsch, 1938Halotudora Watters, 2006Licina Gray, 1847Paradoxipoma Watters, 2014Sallepoma Bartsch, 1946Samanicola Watters, 2006Superbipoma Watters & Larson, 2017Tudora Gray, 1850Tudorina de la Torre & Bartsch, 1941Tudorisca Henderson & Bartsch, 1920Turrithyra de la Torre & Bartsch, 1938Tessaripoma Watters, 2016Incertipoma Bartsch, 1946

Distribution

Island of Hispaniola and the Bahama Archipelago.