Taxonomy and phylogenetic analysis of the South American genus

Abstract

The systematics of Philodromidae is far from complete, especially for the Neotropical genera. Among these, Petrichus Simon, 1886 is a poorly known genus restricted to arid and semi-arid environments of South America. In this work, we performed a total-evidence analysis to assess the phylogenetic relationships of Petrichus and revised the taxonomy. Petrichus is monophyletic and closer to Titanebo and the New World Ebo. Within Petrichus, two clades are obtained: the Eremean Clade, containing five species displaying a Neotropical distribution; and the Patagonian Clade, with the seven species inhabiting southern South America. Our results also support a previous hypothesis on the phylogenetic relationships within Philodromidae. Thanatini is monophyletic and includes Fageia and Berlandiella, although this is not statistically supported, whereas Philodromini emerges as paraphyletic. We propose Philodromini be expanded to contain all genera having eyes on tubercles analysed in this work plus the closely related Halodromus, whereas the circumscription of Thanatini should await future phylogenetic analyses with new evidence. As for taxonomic proposals, we synonymise Bacillocnemis Mello-Leitão, 1938 with Petrichus, Petrichus ornatus Schiapelli & Gerschman, 1942 and P. luteus (Nicolet, 1849) with P. junior (Nicolet, 1849), P. lancearius Simon, 1905 with P. tullgreni Simon, 1902; we transfer P. corticinus Mello-Leitão, 1944 to Misumenoides Pickard-Cambridge, 1900 (Thomisidae); and P. fuliginosus (Nicolet, 1849), P. cinereus Tullgren, 1901, P. sordidus Tullgren, 1901 and P. zonatus Tullgren, 1901 are regarded as nomina dubia. In total, 13 species are recognised for the genus, of which four are new (described by Griotti & Grismado): P. spira, from western Argentina, P. patagoniensis, from south-western Argentina, P. roigjunenti, from Argentina and Chile and P. eremicus, from north-central Chile. ZooBank: http://zoobank.org/References/1220255e-6431-45c2-adfe-ed58d1f89b17

Solving a running crab spider puzzle: delimiting Cleocnemis Simon, 1886 with implications on the phylogeny and terminology of genital structures of Philodromidae

“…The basic division of Philodromidae into two groups named Thanatini and Philodromini by Schick [ 6 ] and also recovered by Wheeler et al [ 5 ] was obtained at least in part in our results. Conversely, Griotti et al [ 8 ] recovered only Philodromini, with the Thanatini groups scattered at the basis of the tree. Following the rise of Philodrominae to family level by Homann [ 2 ], the use of subfamilies instead of tribes to name the two main groups of the family should be straightforward.…”

“…However, Muster [ 3 ] did not apply any formal taxon category to the taxa recovered in his analysis, as his “Philodromini” was a paraphyletic assemblage containing a “Thanatini” distally inserted in his phylogeny. On the other hand, Wheeler et al [ 5 ] and Griotti et al [ 8 ] just referred to the old usage of tribe names by Schick [ 6 ]. We consider the two main branches of Philodromidae as two subfamilies, Philodrominae new stat.…”

“…1 ). The position of Titanebo was already a point of disagreement between the preferred tree in the morphological analysis of Muster [ 3 ], where it was considered sister-group to Thanatini and other ill-placed “Philodromini” taxa, and the molecular analyses of Wheeler et al [ 5 ], where it was recovered as sister group to remaining Philodromini, and the molecular and morphological analysis of Griotti et al [ 8 ], where a non-monophyletic Titanebo was placed within Philodromini. Our analyses indicate another possibility, with Titanebo as sister-group to both subfamilies, as already recovered in the implied weighted analysis of Muster [ 3 ].…”

“…In contrast to Muster [ 3 ], Thanatini was recovered as the sister group to a monophyletic group comprising all other five Philodromini genera sampled by Wheeler et al [ 5 ]. The only Philodromidae phylogeny in which Thanatini did not emerge as monophyletic was the one by Griotti et al [ 8 ] based on molecular and morphological data, with Thanatini groups placed as a polytomy at the basis of the family. By contrast, it supported an expanded composition of Philodromini including Pulchellodromus Wunderlich, 2012, Pagiopalus Simon, 1900, Pedinopistha Karsch, 1880 and Petrichus Simon, 1886.…”

“…Regarding the 16 Neotropical genera of Philodromidae, only three of them were formally revised in the last decades: Berlandiella Mello-Leitão, 1929 by Lise & Silva [ 9 ], Gephyrellula Strand, 1932 by Santos & Rheims [ 10 ] and Petrichus by Griotti et al [ 8 ]. Among the remaining Neotropical genera, Cleocnemis Simon, 1886 has probably the most troublesome taxonomic situation.…”