Phylogenetic Placement of the Extinct Etheostoma sellare and Other Darters with a Compilation of Morphological Character State Polarizations for Darters
Phylogenetic placement of most species of darters is reasonably well understood regarding their closest relatives. However, an exception is the apparently extinct Etheostoma sellare. In this paper, we included E. sellare in a phylogenetic analysis with 62 extant species representing one or more species from all previously recognized darter subgenera. The analysis included 77 new, or previously proposed, polarized, morphological characters for E. sellare and those characters plus reported molecular sequences (RAG1) for the extant species. A parsimony analysis of concatenated data for each species produced nodes congruent with the subgeneric taxonomy of darters and established unambiguous placement for the morphologically distinctive E. sellare placed in the newly created subgenus Mooreichthys to resolve a previous triotomy in which the single taxon was grouped with subgenera Poecilichthys and Litocara. Unique morphological or nucleotide synapomorphies support the monophyly of the subfamily Etheostomatinae and the most basal genus Percina sister to sister genera Ammocrypta and Etheostoma. Other unique synapomorphies support relationships within genus Percina, a close relationship of subgenus Allohistium to a clade containing subgenera Etheostoma + Ulocentra + Nanostoma, rather than to subgenus Nothonotus, and the monophyly of subgenus Catonotus. Relationships of some species, including sisters E. mariae and E. parvipinne, remain uncertain.
States of character 10. (A) P. flavescens, (B) E. punctulatum, (C) E. tetrazonum, (D) E. vitreum, (E) A. clara, (F, G) A. beanii, and (H) A. pellucida. Pd = predorsal bone, 1P = first proximal radial pterygiophore, and 1–9 = neural processes of 1–9 vertebrae. Scale bar = 1.0 mm. Anterior to left, all lateral views. Numbers with decimals are character.character state.
States of characters 11–17. (A) P. flavescens, (B) E. lynceum, (C) E. olivaceum, (D) E. nigrum, (E) P. flavescens, (F) E. chlorosoma, (G) E. flavum, (H) E. nigrum, (I) E. cinereum, (J) E. stigmaeum, (K) P. flavescens, (L) E. zonistium, (M) E. sagitta, (N) E. olivaceum, (O) A. vivax, and (P) A. pellucida. E 1 = epibranchial 1, I = interarcual cartilage, P 1 = pharyngobranchial 1, r = ray, U = uncinate process, and black = cartilage. (A–D, H–J) Anterior to left, lateral view; (E–G) anterior to left, dorsal view; (K–P) left branchial elements, anterior to top, dorsal view. (A–G, K–P) Scale bar = 1.0 mm, (H, J) scale bar = 0.5 mm, and (I) scale bar = 0.75 mm. Numbers with decimals are character.character state.
States of characters 18–33. (A) E. blennius, (B) E. blennioides, (C) E. euzonum, (D) E. tallapoosae, (E) E. osburni, (F) E. euzonum, (G) E. cinereum, (H) E. nigrum, (I) E. rupestre, (J) E. edwini, (K) E. gracile, (L) E. chlorosoma, (M) P. flavescens, (N) E. osburni, (O) E. stigmaeum, (P) P. flavescens, (Q) A. vivax, (R) A. beanii, (S) P. sciera, (T) E. zonistium, (U) E. euzonum, (V) E. nigrum, (W) E. histrio, (X) E. blennius, (Y) A. pellucida, (Z) E. tetrazonum, and (A′) A. beanii. All anterior to left. (A–G) Dorsal view of left side components, (H–L) mesial view of right side components, (M–O, R–A′) left lateral view, and (P, Q) ventral view. Black is cartilage. Scale bar = 1.0 mm. Numbers with decimals are character.character state.
States of characters 31–47. (A) P. copelandi, (B) P. flavescens, (C) E. tuscumbia, (D) A. pellucida, (E) E. osburni, (F) E. mariae, (G) E. blennioides, (H) E. inscriptum, (I) P. sciera, (J) E. zonale, (K) E. histrio, (L) E. rupestre, (M) E. tuscumbia, (N) E. vitreum, (O) P. flavescens, and (P) E. nigrum. All anterior to left, lateral view. Scale bar = 1.0 mm. ioc = infraorbital canal, PC 2 = postcleithrum 2, PC 3 = postcleithrum 3, and soc = supraorbital canal. 2, 5, and 6 = infraorbital bones. Dark colors identify partly enclosing or enclosing components of the infraorbital canal of infraorbital bones 2–6. Numbers with decimals are character.character state.
States of characters 41–46, 48–54, and 66. (A) A. asprella, (B) E. rupestre, (C) E. simoterum, (D) E. blennius, (E) E. flavum, (F) E. barrenense, (G) E. edwini, (H) P. flavescens, (I) E. sellare, (J) E. kanawhae, (K) E. tetrazonum, (L) E. baileyi, (M) P. flavescens, (N) E. camurum, (O) E. rafinesquei, (P) P. cymatotaenia, (Q) E. flavum, (R) E. blennius, (S) E. tetrazonum, and (T) E. baileyi. All anterior to left, lateral view. (L) Scale bar = 0.6 mm, all others = 1.0 mm. ioc = infraorbital canal, ll = lateral line, pmc = preoperculomandibular canal, and soc = supraorbital canal. (H–L) Black highlights infraorbital canal elements. (S) Black represents cartilage and bony metapterygoid flange, (T) black represents cartilage. Numbers with decimals are character.character state.
States of characters 51–64. (A) E. coosae, (B) E. barrenense, (C) E. gracile, (D) E. vitreum, (E) E. barrenense, (F) E. osburni, (G) E. blennius, (H) E. swannanoa, (I) E. variatum, (J) P. flavescens, (K) E. tuscumbia, (L) E. camurum, (M) P. flavescens, (N) E. hopkinsi, (O) P. sciera, (P) E. tallapoosae, (Q) E. blennioides, (R) E. osburni, and (S) E. rafinesquei. All anterior to left, lateral view. Scale bar = 1.0 mm. Numbers with decimals are character.character state.
States of characters 65, 67–76. (A) P. flavescens, (B) E. swannanoa, (C) E. barrenense, (D) E. mariae, (E) P. copelandi, (F) E. blennius, (G) E. pyrrhogaster, (H) E. blennioides, (I) E. rupestre, (J) E. thalassinum, (K) P. flavescens, (L) P. flavescens, (M) A. asprella, (N) E. spectabile, (O) E. nigrum, (P) E. olivaceum, (Q) E. sagitta, (R) E. flavum, (S) A. beanii, (T) E. baileyi, (U) E. rafinesquei, (V) E. hopkinsi, (W) E. punctulatum, and (X) E. tuscumbia. (A–C, K–P, T–X) Anterior to left, lateral view, (D–H) anterior to top, ventral view, (I–J) anterior view, right side, (Q–S) dorsal or near dorsal view, anterior to top. I–IV = hypurals 1–4. (O) Scale bar = 0.5 mm, all others = 1.0 mm. Numbers with decimals are character.character state.
Reweighted, stable, fully resolved parsimony cladogram. Nodes alphabetically labeled. Node support is in Appendix 3. TL = 187.64375, CI = 0.6447, RI = 0.8898, RC = 0.5737.
Contributor Notes
Associate Editor: D. Buth.