|Basic info||Taxonomic history||Classification||Relationships|
|Morphology||Ecology and taphonomy||External Literature Search||Age range and collections|
Trilobita - Redlichiida - Holmiidae
If no rank is listed, the taxon is considered an unranked clade in modern classifications. Ranks may be repeated or presented in the wrong order because authors working on different parts of the classification may disagree about how to rank taxa.
|B. S. Lieberman 1999||Anterior cephalic border developed as rounded ridge, prominently separated by furrow from extraocular area; frontal lobe contacts anterior border furrow, lateral margins distal of lateral margins of L0, expands prominently dorsally; anterolateral margins of frontal lobe prominently separated from extraocular area by furrow (not anterior border furrow); length (sag.) of L4 equal to 1 to 1.1 times length of L0 and L1; dorsal notch in ocular lobe where it contacts lateral margins of frontal lobe; S3 evenly convex, medial and distal tips as far forward; anterodistal margins of L3 formed by axial furrows; distal margin of L3 straight; lateral margins of glabella opposite L2 diverging anteriorly; medial and distal tips of S2 as far forward; S1, S2 and S3 conjoined medially; posterior edge of ocular lobe opposite distal tip of S0; line from posterior margin of ocular lobe to junction of lobe with glabella forms roughly 5 to 15 degree angle relative to sagittal line; L0 with spine posterior of midline; lat- eral lobes absent from L0; intergenal angle with small spine directly behind distal tip of oc- ular lobe; intergenal angle forms roughly 10 to 15 degree angle with transverse line; extraoc- ular area prominently vaulted, width (tr.) at L1 45% to 55% width of glabella at L1; genal spine angle opposite distal margin of L0; lateral margin of genal spine near spine angle forms roughly 30 to 40 degree angle with sagittal line; genal spine extends back roughly 8 thoracic segments; thoracic pleural spines on first four segments extend back only one segment; lat- eral margins of spines inclined at 40 to 50 degree angle relative to sagittal line; posterior mar- gins of first four thoracic segments near spines flex slightly anteriorly; length (sag.) and width (tr.) of pygidium roughly equal; posterior margin of pygidium roughly transverse.|