Phylogenetic relationships among early crinoids are evaluated by maximizing parsimonious-informative characters that are unordered and unweighted. Primarily Tremadocian–Darriwilian (Early–Middle Ordovician) taxa are analysed. Stratigraphic congruence metrics support the best phylogenetic hypothesis derived using parsimony methods. This study confirms the traditionally recognized lineages of Palaeozoic crinoids and provides new information on the branching order of evolving lineages. Camerates are basal crinoids with progressively more tipward groups (from an Ordovician perspective) being protocrinoids, cladids (paraphyletic), hybocrinids and disparids. The Protocrinoida should be maintained, but the Aethocrinida should be placed within the Cladida. The results of this study identify phylogenetic structure amongst the major early crinoid lineages and delineate the relative positions of crinoid higher taxa along a tree. Each valid higher taxon discussed herein requires a comprehensive treatment to delimit within-lineage phylogenetic relationships.
AKRW-CrinoidPhylogenyDryadAppendix1
Appendix 1. Listing of characters and character states coded for analyses.
AKRW-CrinoidPhylogenyDryadAppendix2
Appendix 2. “Wildcard" taxa identified from Adams consensus of all 38,724 trees resulting from an unordered, unweighted parsimony analysis of the character matrix including all taxa.
AKRW-CrinoidPhylogenyDryadAppendix3
Appendix 3. Exemplar species used in analyses; * indicates type species.
AKRW-RevisedDryadFig1
FIG. 1. Strict consensus of all taxa and characters of this study. All results from PAUP 4.0a142; analysis resulted from heuristic search with random addition and 100 repetitions. A, strict consensus of 38,724 most-parsimonious trees, tree length 749, CI=0.399, RI=0.567, RC=0.226.
AKRW-RevisedDryadFig2
FIG. 2. Phylogenies for all Tremadocian through Darriwilian crinoids. All results from PAUP 4.0a142; all analyses resulted from heuristic search with random addition and 1000 repetitions. A, strict consensus of 2350 most-parsimonious trees, tree length 508, CI=0.429, RI=0.548, RC=0.235; B, 50% majority-rule tree of Fig. 2A.
AKRW-RevisedDryadFig3
FIG. 3. Phylogenies for all Tremadocian through Dapingian crinoids. All results from PAUP 4.0a142; all analyses resulted from heuristic search with random addition and 1000 repetitions. A, strict consensus of 9 most-parsimonious trees, tree length 267, CI=0.562, RI=0.568, RC=0.319; B, 50% majority-rule tree of Fig. 3A.
AKRW-RevisedDryadFig4
FIG. 4. Phylogram of tree in Ausich et al. (in press, Fig. 2A).
AKRW-RevisedDryadFig5
FIG. 5. Phylogenies for all Tremadocian through Darriwilian crinoids with all taxa used in Ausich et al. (in press, Fig. 2B), plus Adelphicrinus, Cnemecrinus, and Eknomocrinus. All results from PAUP 4.0a142; all analyses resulted from heuristic search with random addition and 1000 repetitions. A, strict consensus of 514 most-parsimonious trees, tree length 447, CI=0.465, RI=0.564, RC=0.262; B, 50% majority-rule tree of Fig. 5A.
AKRW-RevisedDryadFig6
FIG. 6. Phylogram of tree in Ausich et al. (in press, Fig. 3A).
AKRW-RevisedDryadFig7
FIG. 7. Phylogenies for Tremadocian through Darriwilian and three Sandbian and Katian disparids. All results from PAUP 4.0a142; all analyses resulted from heuristic search with random addition and 1000 repetitions. A, tree in Ausich et al. (in press, Fig. 2B) with three Sandbian disparids included, strict consensus of 28 trees, tree length 457, CI=0.481, RI=0.574, RC=0.276; B, 50% majority-rule tree of Fig 7A.
AKRW-RevisedDryadFig8
FIG. 8. Phylogenies for Tremadocian through Darriwilian crinoids coded with lintels (as in Ausich, 1996, 1998a, 1998b). All results from PAUP 4.0a142; all analyses resulted from heuristic search with random addition and 1000 repetitions. A, tree in Ausich et al. (in press, Fig. 3B) with lintel coding, strict consensus of 50 trees, tree length 515, CI=0.431, RI=0.586, RC=0.253; B, 50% majority-rule tree of Fig. 8A.
AKRW-RevisedDryadFig9
FIG. 9. Phylogenies for Tremadocian through Darriwilian crinoids with all taxa used in Ausich et al. (in press, Fig. 2B) plus Merocrinus coded as a cladid. All results from PAUP 4.0a142; all analyses resulted from heuristic search with random addition and 1000 repetitions. A, strict consensus of 156 most-parsimonious trees, tree length 423, CI=0.475, RI=0.572, RC=0.272; B, 50% majority-rule tree of Fig. 9A.
AKRW-RevisedDryadFig10
FIG. 10. Phylogenies for Tremadocian through Darriwilian crinoids with all taxa used in Ausich et al. (in press, Fig. 2B) plus Merocrinus coded as a disparid. All results from PAUP 4.0a142; all analyses resulted from heuristic search with random addition and 1000 repetitions. A, strict consensus tree of 48 most-parsimonious trees, tree length 423, CI=0.475, RI=0.571, RC=0.272; B, 50% majority-rule tree of Fig. 10A.