Here are some representative members of Suborder Phacopina:
Cephalon: proparian sutures (sometimes fused), schizochroal eyes; glabella expands forwards; librigena typically yoked as single piece; hypostome conterminant to impendent, some with no rostral plate; some with genal spines.
Thorax: 10 to (typically) 11 segments, pleurae furrowed, articulating facets distinct, rounded, angular, or spinose tips.
Pygidium: typically smaller than cephalon (but subisopygous in Dalmanitoidea and Acastoidea), smooth or spinose.
Superfamilies: Phacopoidea, Dalmanitoidea, Acastoidea
Characterizations of the three Phacopine superfamilies:
Cephalon: generally with strongly divergent axial furrows (glabella greatly expanding anteriorly), anterior glabellar lobes fused into single anterior tri-composite lobe, frontal area generally lacking (obliterated by large glabella), eyes (when present) typically anterior; genal angle typically rounded, without genal spines (exceptions among Pterygometopidae), vincular furrow generally present.
Thorax: variable, but often with rounded tips.
Pygidium: typically micropygous (Phacopidae) to subisopygous (some Pterygometopidae), not spinose.
Families: Phacopidae, Pterygometopidae
Genera: Ductina, Kainops, Phacops, Pterygometopus, Reedops,
PHACOPIDA includes three Suborders
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