SVP abstracts 2: Barrett and Hopkins mishandle hyaena taxonomy

Cherry-picking taxa
(leading to both taxon exclusion and inappropriate taxon inclusion mars this otherwise earnest study.

From the Barrett and Hopkins abstract:
“The family Hyaenidae today is represented by only four living species, but this constitutes only a small fraction of known taxa from the fossil record. Results from both molecular and morphological analyses have shown disagreement in relationships, while certain hypothesized stem hyaenids and viverroids have received little to no phylogenetic assessment.”

First red flag: In the large reptile tree (LRT, 1749+ taxa; subset Fig. 3) viverroids (= civets), like Nandinia (Fig. 2) nest outside the clade Carnivora. Hyaenas, like Crocuta (Fig. 1), are highly derived carinvorans. Barrett and Hopkins think these two are related to one another based on Gray 1821 and gene studies. In the LRT civets are closer to their marsupial ancestors than to hyaenas, nesting with cats and dogs.

This taxonomic problem goes back to Gray 1821
who created the following clades of unrelated taxa. 

Viverridae (Gray 1821) defined as consisting of the genera Viverra (= large Indian civet), Genetta (= genet), Herpestes (= mongoose), and Suricata (= meerkat).

Viverroidea (Gray 1821, civets, mongooses, hyenas and aardwolves) is not supported by the LRT. Adding taxa lumps and separates these taxa.

Essentially viverroids were neither cat-like (= Felliformes) nor dog-like (Caniformes) carnivorans, a split still accepted by many mammal workers due to genomic results. The LRT (subset Fig. 3) does not agree with these lumps and splits.

Figure 3. Crocuta (hyena) skeleton. Note similarities to Canis (figure 2)

Figure 1. Crocuta (hyena) skeleton. Note similarities to Canis (figure 2)

Continuing from the Barrett and Hopkins abstract:
“These taxa include the percrocutids (bone-crushing, hyena-like viverroids), lophocyonids (extremely hypocarnivorous feliforms), and additional well-preserved, yet unassessed Miocene viverroids.”

Second red flag: Nandina, the palm civet (Fig. 2), and other vivveroids are small, mink-like arboreal taxa with short legs and a long tail. Percrocutids and hyaenas are terrestrial gallopers with a distinctly different morphology from head to toe.

Figure 1. Nandinia, the palm civet, nests as the proximal outgroup taxon to the Carnivora and all other placental mammals.

Figure 2. Nandinia, the palm civet, nests as the proximal outgroup taxon to the Carnivora and all other placental mammals.

Continuing from the Barrett and Hopkins abstract:
“Thus, to combine all available datasets, we performed a total-evidence Bayesian phylogenetic analysis inclusive of a sample of stem-to-derived hyaenids, herpestids, viverrids and other unassessed viverroid taxa.”

This is a classic case of taxon exclusion based on genomic studies. In other words, this study was doomed from the start.

Figure 2. Subset of the LRT focusing on the Carnivora.

Figure 3. Subset of the LRT focusing on the Carnivora.

Continuing from the Barrett and Hopkins abstract:
“The analyzed dataset includes stratigraphic occurrences, 257 morphological characters and mitochondrial genes of all living taxa in the analysis and ancient DNA from the cave hyena (Crocuta crocuta spelaea).”

“All living taxa in the analysis” = which living taxa? Hyaenas and palm civets? The genomic taxon list makes Gray 1821 quite a prognosticator, but neither study is supported when fossil taxa and traits are tested.  Let’s get back to trait (= phenomic) analysis. Genomes yield false positives too often and exclude too many extinct taxa.

Figure 1. Mammals at the base of the Placentalia include the outgroup taxon: Caluromys, a basal placental: Genetta, a basal Carnivora: Eupleres, a basal Volitantia: Ptilocercus, a basal Primates: Microcebus, and basal Glires: Tupaia.

Figure 1. Mammals at the base of the Placentalia include the outgroup taxon: Caluromys, a basal placental: Genetta, a basal Carnivora: Eupleres, a basal Volitantia: Ptilocercus, a basal Primates: Microcebus, and basal Glires: Tupaia.

The transition from marsupial to placental was documented 
here (Figs. 3, 4) where viverrids, like Genetta nested at the base of the Placentalia, far from highly derived hyaenas and separated by ALL OTHER carnivorans.


References
Barrett PZ and Hopkins SS 2020. First total-evidence phylogeny of the hyaenidae and enigmatic viverroids reveals novel relationships. SVP abstracts 2020.
Gray JE 1821. On the natural arrangement of vertebrose animals. The London Medical Repository Monthly Journal and Review 15:296-310

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