Paromomyidae are a taxonomically diverse family of archaic primates known principally from deposits of Paleocene and Eocene age in North America. While often numerically abundant in local mammalian faunas, the various paromomyid taxa are most often represented by isolated teeth and rare dentigerous cranial and dentary fragments. Accordingly, paromomyid interrelationships are on balance poorly understood, and this is especially true for early branching taxa.

These data support a paper naming two new species of Paromomys—long considered the earliest diverging paromomyid—from Paleocene deposits in southwestern Alberta. Paromomys borealis sp. nov. and Paromomys ignis sp. nov. bear closest resemblance to Paromomys depressidens and Paromomys maturus, respectively, and represent the first occurrences of the genus in Canada.

This dataset consists of three files that were used for the Phylogenetic analysis (see Methods) that include the new species in a comprehensive dataset of paromomyid species.

The phylogenetic analysis of all paromomyid species resulted in overall poor resolution. Paromomys was recovered as non-monophyletic—consistent with previous results—with species either in a polytomy or positioned at increasingly crownward positions. In contrast to previous hypotheses, the position of Paromomys as the earliest diverging paromomyid was rendered equivocal. Notably, two recently described species of Ignacius from the Canadian Arctic resolved as sister to Acidomomys to the exclusion of other paromomyids.

When re-using this data, we encourage appropriate attribution.

Phylogenetic analysis—To determine the phylogenetic position of the new paromomyids described herein, we conducted a cladistic analysis using a modified data set from Scott et al. (2023). The analysis included 31 paromomyids—including newly described species of Ignacius from the Canadian high Arctic (Miller et al. 2023) and of Arcius from Quercy, France (Godinot et al., 2021)—as well several non-paromomyid plesiadapiforms as immediate outgroups (enumerated in Scott et al. 2023). The paromomyid status of the early Eocene Arcius ilerdensis López-Torres & Silcox, 2018 from Masia de l’Hereuet, northeastern Spain, has recently been challenged (Beard and Métais, 2023), with the holotype now referred to the apatemyid Heterohyus Gervais, 1848. Accordingly, A. ilerdensis was not included in the analysis pending reassessment of the paromomyid material from Masia de l’Hereuet. The asioryctitherian Ukhaatherium nessovi Novacek, Rougier, Wible, McKenna, Dashzeveg, and Horowitz, 1997 was included as an outgroup to all plesiadapiforms. The matrix, compiled in Mesquite v. 3.81 (Maddison and Maddison, 2023), includes 41 taxa scored for 105 characters (character list and Nexus file available in Supplementary Data 1 and 2). Five characters from Miller et al.’s (2023) matrix were added to the matrix of Scott et al. (2023): the relative height of the I1 laterocone (character 5); the position of the zygomatic relative to M1 (character 28); the steepness of the postprotocingulum slope on M1 (character 37); presence of preprotocingulum on M1 (character 38); and the morphology of the precingulum and mesiobuccal cingulum on M1–2 (character 39). Additionally, changes were made to two characters in the Scott et al. (2023) matrix: character 63 (development of p4 paraconid; character 58 in Scott et al., 2023), in which former character state 0 (“absent”) has been changed to “undeveloped and weakly developed” and former character state 1 (“present”) has been changed to “well-developed”; and character 97 (relief index value for m2; character 92 in Scott et al., 2023), the former states 2 (“0.5<x<0.6”) and 3 (“>0.6”) were combined into a single state 2 (“>0.5”). All characters were weighted equally.

A parsimony analysis was conducted using PAUP 4.0*a169 (Swofford, 2002) using the following commands: (1) outgroup 'Ukhaatherium nessovi', (2) SET MAXTREES=100000; hsearch addseq=random nrep=1000 swap=tbr hold=10;. Previous to the analysis, a total of 11 characters were ordered (1, 13, 19, 33, 77, 78, 88, 91, 97 and 98) and embedded into the Nexus file.