. Bulletin of the British Museum (Natural History), Geology. 176 ORDOVICIAN TRILOBITE FAUNAS spines. The lateral margins are straight and slightly divergent anteriorly; anterior margin arched forwards medially; anterolateral corners angulate. The glabella is convex, with the pseudofrontal lobe occupying the anterior three- fifths; it is of moderately convex profile anteriorly and gives the impression of encroaching onto the fringe in compressed specimens. The poorly preserved anterior lateral glabellar furrows are weakly developed. The median pair, de- limiting the posterior of the pseudofront
. Bulletin of the British Museum (Natural History), Geology. 176 ORDOVICIAN TRILOBITE FAUNAS spines. The lateral margins are straight and slightly divergent anteriorly; anterior margin arched forwards medially; anterolateral corners angulate. The glabella is convex, with the pseudofrontal lobe occupying the anterior three- fifths; it is of moderately convex profile anteriorly and gives the impression of encroaching onto the fringe in compressed specimens. The poorly preserved anterior lateral glabellar furrows are weakly developed. The median pair, de- limiting the posterior of the pseudofrontal lobe, are better developed and consist of elongate (tr.), rather shallow pits. The posterior pair are again elongate pits, but are directed slightly anteromedially. A small median glabellar node is situated about half-way along the glabella. A coarse reticulate pattern is developed medially on the glabella. Alae extend posteriorly from the rear of the pseudofrontal lobe. A weakly developed occiput is present. The occipital ring is short {sag.) consisting of little more than a median continuation of the low ridge forming the posterior margin of the genal regions. The occipital furrow is shallow; no occipital spine is developed. The shallow axial furrows are most clearly defined anteriorly where a pair of anterior fossulae are developed. The genal regions are quadrant-shaped and apart from the steeply declined outer margin are only slightly convex. Traces of a course reticulation are present distri- buted in the typical trinucleid manner. In some specimens a small lateral eye tubercle appears to be developed on each gena, close to the axial furrows and slightly anterior of the median lateral glabellar furrows, although eye ridges are lacking (PI. 16, fig. 4). The posterior margin is upturned to form a low ridge-like border. Fig. 13. Reconstruction of the cephalon of Telaeomarrolithus intermedins sp. nov. in dorsal view. c. x Please note that these images are extracted from
Size: 1892px × 1320px
Photo credit: © Book Worm / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookauthorbritishmuseumnaturalhistory, bookcentury1900, bookcoll
