Odontopleuridae

Classification
Phylum: Arthropoda
Class: Trilobita
Order: Lichida
Family: Odontopleuridae (Burmeister ,1843)
Cincinnatian Genera: Acidaspis

Geologic Range
Early Ordovician – Late Devonian

Common Paleoecology
Odontopleuridae is an extinct family of fast-moving low-level epifaunal carnivores.

Description of the Family

  • A distinct group of very spinose trilobites.
  • Cephalon convex, the glabella tapers forward or sub-parallel and maximum width generally at the occipital ring.
  • Thorax usually has 8-10 segments, at the end of which are 2-3 pairs of spines.
  • Pygidium short, subtriangular in outline, pleural regions horizontal; paired spines on border.
  • External surface rarely smooth, generally with thorn-like spines or tubercles, arrangement of larger spines or tubercles may be symmetrical.

Published Descriptions

Treatise on Invertebrate Paleontology, Part O (1959):

  • “Cephalon convex, posteromedian region high above anterolateral margin; glabella with maximum width generally at occipital ring, subparallel-sided or tapering forward; occipital ring may be elongated behind adjacent part of genal regions and bear lateral lobes, with median or paired spines or rubercles characteristic; 2 or 3 pairs of lateral glabellar lobes present; genal regions or may be inside and behind this point, eye ridges curving forward to merge with anterolateral margins of frontal glabellar lobe; anterior sections of facial sutures running forward-inward, posterior sections outward-backward, sutural ridges characteristic; usually stout librigenal spines present, base merging into posterolateral cephalic borders; row of shorter spines arising from outer edge of borders of librigenae, progressively shorter anteriorly; notches in borders of librigenae adjacent to anterior sections of sutures. Rostral plate short (sag., exsag.) and wide (tr.). width and length of hypostoma subequal or width greater than length, posterolateral margins rounded; with convex middle body, faint middle furrows running backward and slightly inward from depression at anterolateral corners of middle body; lateral and posterior borders moderately wide; small anterior wing, no wing process, posterior wing small or absent. Thorax with 8 to 10 segments; axis convex; pleurae horizontal, with or without pleural furrow dividing them into 2 convex bands, with short anterior pleural spine or spines, long posterior pleural spine directed horizontally outward and progressively more backward toward rear. Pygidium short, subtriangular in outline; axis with 2 or 3 rings (3rd faint); pleural regions horizontal; paired spines on border, with or without median posterior spine (one pair of border spines may be larger than others and directed horizontally or upward, or large pair of spines may arise from pleural region), large spine connected by raised ridge to 1st axial ring. External surface rarely smooth, generally with thorn-like spines or tubercles, granules between them, arrangement of larger spines or tubercles may be symmetrical.”

Acidaspis