Hylocereeae

Korotkova, Nadja, Borsch, Thomas & Arias, Salvador, 2017, A phylogenetic framework for the Hylocereeae (Cactaceae) and implications for the circumscription of the genera, Phytotaxa 327 (1), pp. 1-46 : 9

The Hylocereeae clade and its major subclades

A Hylocereeae clade is highly supported in all analyses (1 PP, 95% MLBS, 98% JK), but the Hylocereeae as currently circumscribed are polyphyletic ( Fig. 2 ). They would become monophyletic if Acanthocereus (Engelmann ex A. Berger) Britton & Rose were to be included and Strophocactus was excluded.

The well supported clade of the Hylocereeae as depicted here includes four main lineages: first, the Acanthocereus (incl. Peniocereus subg. Pseudoacanthocereus ) clade, Acanthocereus with three species included is found as a highly supported lineage (1 PP, 81 % MLBS, 90 % JK), second, the two species of Aporocactus (represented by several samples) are depicted in an only weakly supported lineage, and two larger subclades that we refer to as the hylocereoid clade and the phyllocactoid clade.

The hylocereoid clade (1 PP,65% MLBS, 68% JK) contains the genera Hylocereus , Selenicereus , and Weberocereus . Hylocereus and Selenicereus together form a highly supported clade (1 PP, 98% MLBS, 99% JK). Selenicereus is polyphyletic and for the most part forms a grade with a highly supported (1 PP, 91% MLBS, 94% JK) monophyletic genus Hylocereus nested in it. Five species of Weberocereus (including the type species, W. tunilla Britton & Rose ) are recovered as a monophyletic group (1 PP, 82 % MLBS, 80 % JK) and are sister to the Selenicereus / Hylocereus clade. However the remaining two species [ W. tonduzii (F.A.C. Weber) G.D. Rowley and W. glaber (Eichlam) G.D. Rowley , including subsp. glaber and subsp. mirandae (Bravo) U. Guzmán ] appear within the Selenicereus grade. The phyllocactoid clade is maximally supported by Bayesian Inference but not recovered by Maximum Likelihood and only supported with 53% JK. It contains four subclades corresponding largely to the genera Epiphyllum , Disocactus and Pseudorhipsalis , yet Pseudorhipsalis is found polyphyletic with P. ramulosa (Salm-Dyck) Barthlott resolved separately from Pseudorhipsalis in a tritomy with Epiphyllum and Disocactus .

Strophocactus falls entirely outside the Hylocereeae clade and is itself polyphyletic. Its three species are resolved at two different positions with high to maximal support. The first clade (1 PP, 82% MLBS, 82% JK) contains S. witti (K. Schumann) Britton & Rose , Pseudoacanthocereus sicariguensis (Croizat & Tamayo) N.P. Taylor, P. brasiliensis (Britton & Rose) F. Ritter and Neoraimondia herzogiana (Backeberg) Buxbaum & Krainz. The second clade (1 PP, 98% MLBS, 99% JK) is resolved within the Echinocereeae and contains Strophocactus testudo (Karwinsky ex Zuccarini) Ralf Bauer and S. chontalensis (Alexander) Ralf Bauer.

Figures

FIGURE 2A. Majority-rule consensus tree from Bayesian inference.Values above branches are Posterior Probabilities (left) and Bootstrap support values from Maximum Likelihood (10.000 replicates) calculated with RAxML GUI using the “ML + thorough bootstrap” option, values below branches are Jackknife support values (10.000) calculated in PAUP. (-- denotes ML BS support below 50, n.f.: node not found). Taxon names in the cladogram reflect hitherto accepted names (Bauer 2003a, Hunt 2006), with the exception of new names in Disocactus published by Cruz et al. (2016). The new/updated generic concepts presented here are annotated with brackets.