Pyrisinellidae

Diagnosis. Colony encrusting and multiserial. Autozooids distinct, oval, separated by deep furrows. Gymnocyst narrow, visible around entire circumference of zooid, often enlarged proximally. Cryptocyst extensively developed, depressed, flat and granular. Frontal surface of autozooids marked by pear-shaped ridge formed proximally and laterally by mural rim and distally by distal rim of opesia. Opesiules absent or present but few in number and small. Orifice trifoliate or semielliptical. Oral spines present, closely spaced, forming an arch distally around the orifice. Cryptocystal closure plates often developed. Ovicell hyperstomial, resting on distal zooid and indenting its mural rim. Growing edge stepped, revealing windows of pore chambers, that of the distal pore chamber the largest, ovoidal and facing frontally. Avicularia absent or present and variously adventitious, interzooidal or vicarious; rostrum acuminate or rounded; pivotal bar entirely calcified or represented by two condyles.

Type genus. Pyrisinella gen. nov.

Remarks. This new family is erected to accommodate two new genera (Pyrisinella and Spinisinella) plus an existing genus (Setosinella) which share a sufficient numbers of skeletal morphological characters to suggest that they represent a clade of anascan-grade neocheilostomes distinguishable from other ‘calloporids’. In all three genera, the small autozooids have a salient mural rim extending to the proximolateral corners of the opesia and joining with the opesial rim to form a pear-shaped ridge around the cryptocyst and opesia, an arch of oral spines over the orifice, and a prominent hyperstomial ovicell. A fourth genus, Megapora, is tentatively referred to Pyrisinellidae, although it differs from the other three genera in that the proximal part of the pear-shaped ridge is located within the cryptocyst rather than representing a true mural rim marking the boundary between the cryptocystal and gymnocystal components of the frontal wall. Although a few genera of Microporidae Gray, 1848 possess a similar pear-shaped ridge, they differ from pyrisinellids in one or more of the following characters: immersed ovicells, lack of gymnocyst, and presence of connecting tubes between the zooids (as in Mollia Lamouroux, 1816).

Pyrisinella is chosen as the type genus of the new family for the following reasons: (1) Spinisinella is represented by only a single small colony whereas Pyrisinella is abundant; (2) using Setosinella as the type genus would result in a family name confusingly similar to Setosellidae Levinsen, 1909; and (3) Megapora is only provisionally assigned to the new family.

Stratigraphical distribution. Cretaceous (Cenomanian or Turonian) to Miocene (Langhian),?Recent.