Diplotrypa

COMPARISON

DIAGNOSIS. — Massive, variably shaped colonies, exozone poorly developed. Budding pattern interzooecial. Zooecial arrangement disordered; zooecia gradually expand distally through early ontogeny and curve outward toward colony surface; zooecia characterised by ontogenetic progression of mesozooecia expanding into autozooecia. Mesozooecial stage of early zooecial ontogeny extended; after mesozooecial stage, diaphragms widely spaced in proximal ends and closely spaced in distal ends of mesozooecia; mesozooecia occasionally fuse to form autozooecia; mesozooecia commonly isolate autozooecia. Autozooecial apertures polygonal to rounded. Autozooecial walls commonly thin throughout colony and composed of finely crystalline microlaminae. Diaphragms thin, planar, concave, convex or cystoidal, variably spaced. Acanthostyles rare. Maculae usually consisting of macrozooecia.

Diplotrypa Nicholson, 1879 differs from other genera of the Family Halloporidae by its massive colony form and thin zooecial walls.

OCCURRENCE. — Lower Ordovician to Upper Silurian; North America, Asia, and Europe.

TYPE SPECIES. — Monticulipora (Diplotrypa) petropolitana Nicholson, 1879 by original designation (non Favosites petropolitanus Pander, 1830). Sweden; Middle Ordovician.