. Bulletin of the British Museum (Natural History), Geology. 170 R. A. FORTEY & R. M. OWENS Microparia (Microparia) teretis sp. nov. (Figs 48, 49) Holotype. Axial shield, BGS Prl991. Paratypes. Incomplete dorsal exoskeleton SM A44523; cranidium It. 19634; pygidia It. 19632— 3, NMW ; free cheek ; thorax and pygidium NMW Type locality and horizon. Llanfallteg Formation, Rhyd-y-wrach, near Llanfallteg; earliest Llanvirn. Stratigraphical range. Llanfallteg Formation, spanning the Arenig-Llanvirn boundary. Type section, 20 m below boundary (52L); earliest Llanvirn
. Bulletin of the British Museum (Natural History), Geology. 170 R. A. FORTEY & R. M. OWENS Microparia (Microparia) teretis sp. nov. (Figs 48, 49) Holotype. Axial shield, BGS Prl991. Paratypes. Incomplete dorsal exoskeleton SM A44523; cranidium It. 19634; pygidia It. 19632— 3, NMW ; free cheek ; thorax and pygidium NMW Type locality and horizon. Llanfallteg Formation, Rhyd-y-wrach, near Llanfallteg; earliest Llanvirn. Stratigraphical range. Llanfallteg Formation, spanning the Arenig-Llanvirn boundary. Type section, 20 m below boundary (52L); earliest Llanvirn of Iocs 50, 52; and Scolton railway cutting, loc. 55. Diagnosis. Microparia with broadly oval exoskeleton less than twice as long as wide; thorax and pygidium about equal in length, and cranidium not greatly longer. Cranidium broad (tr.) for genus, poorly defined palpebral rims. Pygidium almost twice as wide as long with relatively wide border which is distinctly defined laterally. Name. 'Smoothed off'. Description. The holotype preserves what is probably the original convexity: low transversely, with a gently swollen cranidium, narrowly but steeply down-turned around its anterior edge. The exoskeleton is less elongate than Microparia broeggeri, width across the mid-part of the thorax more than half sagittal length. Cranidial outline is very broadly and gently rounded about mid-line, cranidial length only about two-thirds width (length/width ratio in the range 0-62-0-75). Maximum cranidial width achieved shortly in front of posterior cranidial margin. Otherwise dorsal cranidial surface is devoid of features; specimens do not show palpebral Fig. 48 Reconstructions of dorsal exoskeleton of Microparia {Microparia) broeggeri (Holub), left, and axial shield of M. (Microparia) teretis sp. nov., right, both x 3 Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of the
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