Norwoodia boninoi (Robison & Babcock, 2011)


Norwoodia with wide anterior and lateral cephalic border furrow. Glabella short, slightly tapered, diminishing in relative length through ontogeny; lateral furrows weak to effaced. Occipital furrow weak to effaced. Occipital ring, with medial node, merging rearward into long, stout, variably flattened occipital spine. Palpebral lobes about half as long as glabella, opposite anterior glabella. Anterior sections of facial suture weakly divergent, posterior sections diverge laterally and slightly forward to border furrow and then gently curve rearward to lateral cephalic margin. Genal spines long and stout, similar in length to occipital spine, all three approximately reaching an imaginary transverse line near thoracic-pygidial boundary. Cephalic doublure with small anterior rostellum and posterior median suture.

Thorax containing nine segments; unusually narrow and subcircular in outline, being slightly more than half as wide as maximum width of cephalon. Fourth thoracic segment having exceptionally long, slender, posteriorly directed, medial spine, its length greater than
exoskeleton without spine.

Pygidium tiny, short, and alate; width more than three times length; axis with two rings.

After Enrico Bonino, for promoting knowledge of trilobites.

Norwoodia boninoi is a macrocephalic trilobite that has a general morphology reminiscent of, and probably convergent with, some mid-Paleozoic bellinurid xiphosurans.