Taxon exclusion in the Everson et al 2016 study on Madagascar tenrecs

Everson et al 2016 wrote:
“The family Tenrecidae (tenrecs) is one of only four extant terrestrial mammal lineages to have colonized and diversified on Madagascar.

Colonized? No. Stranded and isolated before the Cretaceous split? Yes.

“We reconstructed the phylogeny of Tenrecidae using multiple loci from all recognized extant species and estimated divergence timing using six fossil calibrations within Afrotheria. All phylogenetic analyses strongly support monophyly of the Malagasy tenrecs, and our divergence timing analysis places their colonization of the island at 30–56
Ma.”

Afrotheria is a genomic clade not supported by the large reptile tree (LRT, 2324 taxa) which is built using traits from extant and fossil taxa.

Everson et al 2016 did not include any of the fossil taxa shown above in their tenrec (Hemicentetes + Tenrec) study.

Everson et al concluded,
“Our inclusive taxon sample and well-resolved phylogeny allow for a revised taxonomy of extant tenrecs reflective of their evolutionary history.

Not inclusive. Did not include fossils and odontocetes (Fig 3).

“Perhaps most notably, we formally re-elevate the African otter shrews (formerly Potamogalinae) to familial rank (Potamogalidae). Allman’s (1865, 1866) decision to name Potamogalidae in his description of Potamogale velox stemmed not from its distinctiveness from tenrecids but rather its perceived similarities to Solenodon, a Caribbean genus long allied with tenrecs and African otter shrews (Dobson 1882; Simpson 1945; McDowell 1958) but now placed in a separate superordinal clade based on analyses of molecular, morphological, and paleontological data (Roca et al. 2004; O’Leary et al. 2013).”

In the LRT Solenodon nests with Potamogale (Fig 2) on a branch within the Anagalia (Anagale + Siamotherium at its base) – but on a separate branch of moonrats (Desmana) and hedgehogs (Erinaceus) apart from tenrecs and odontocetes.

“Potamogalidae has been recognized as the sister family to Tenrecidae sensu stricto by a number of Szalay 2004; Seiffert et al. 2007), and no explicit or compelling opposition to this arrangement has been expressed in the recent literature.”

The LRT provides the compelling evidence not found by the Everson et al study, which suffers from taxon exclusion = cherry-picking taxa.

“Morphologically, African otter shrews are distinct from all Malagasy tenrecs, and every other taxon with which they have been allied, in lacking clavicles and possessing syndactylous (conjoined) second and third hindfoot digits (reviewed in Guth et al. 1959; Guth et al. 1960; Olson 1999).

It’s not a good idea to list traits shared or distinct in cherry-picked taxa due to possible convergence. The LRT indicates convergence is rampant on chordates. Better to recover clades first, then perhapslist shared traits with the proviso that convergence is out there.

Doublerooted canines and absent or indistinct hindfoot thenara (integumental pads) also set African otter shrews apart from tenrecs (Olson 1999), as does the aforementioned absence of a lacrimal foramen (Olson and Goodman 2003, but see Asher and Hofreiter 2006).

Ditto the above admonishment.

Collectively, these differences, in addition to the inferred antiquity of the potamogalid lineage (Meredithet al. 2011; this study), seem more than sufficient to warrant its recognition as a family distinct from Malagasy tenrecs.”

The LRT supports this distinct family interrelationship.

Figure 1. Potamogale velox, the giant otter shrew nests with Scutisorex (Fig. 2), the hero shrew, in the large reptile tree. ” data-image-caption=”

Figure 1. Potamogale velox, the giant otter shrew nests with Scutisorex (Fig. 2), the hero shrew, in the large reptile tree.

” data-medium-file=”https://pterosaurheresies.wordpress.com/wp-content/uploads/2016/11/potamogale_velox_588.jpg?w=300″ data-large-file=”https://pterosaurheresies.wordpress.com/wp-content/uploads/2016/11/potamogale_velox_588.jpg?w=584″ tabindex=”0″ role=”button” class=”size-full wp-image-24802″ src=”https://pterosaurheresies.wordpress.com/wp-content/uploads/2016/11/potamogale_velox_588.jpg” alt=”Figure 1. Potamogale velox, the giant otter shrew nests with Scutisorex (Fig. 2), the hero shrew, in the large reptile tree.” width=”584″ height=”511″ />

Figure 2. Potamogale velox, the giant otter shrew nests apart from Scutisorex (Fig. 2), the hero shrew, in the large reptile tree.

You might think shrews
would be in this clade of small terrestrial taxa, but shrews nest with arboreal Apatemyidae in the LRT. Here (Fig 3) is the current hypothesis of interrelationships in the LRT focused on Anagalia. These are the taxa that should have been included in the Everson et al paper.

Figure 3. Subset of the LRT focusing on the Anagalia, a clade that includes elephant shrews, moles, tenrecs and odontocetes. ” data-image-caption=”

Figure 3. Subset of the LRT focusing on the Anagalia, a clade that includes elephant shrews, moles, tenrecs and odontocetes.

” data-medium-file=”https://pterosaurheresies.wordpress.com/wp-content/uploads/2024/09/anagalia_lrtcladogram588.jpg?w=118″ data-large-file=”https://pterosaurheresies.wordpress.com/wp-content/uploads/2024/09/anagalia_lrtcladogram588.jpg?w=404″ tabindex=”0″ role=”button” class=”size-full wp-image-88555″ src=”https://pterosaurheresies.wordpress.com/wp-content/uploads/2024/09/anagalia_lrtcladogram588.jpg” alt=”Figure 3. Subset of the LRT focusing on the Anagalia, a clade that includes elephant shrews, moles, tenrecs and odontocetes. ” width=”584″ height=”1482″ />

Figure 3. Subset of the LRT focusing on the Anagalia, a clade that includes elephant shrews, moles, tenrecs and odontocetes.

One of the problems
with learning from textbooks and lectures at the university level is the sense that these sources represent the basic facts and clades known in 2024. Unfortunately this sense is a self-perpetuating myth in which present and future textbook authors and professors cite past textbook authors and professors. And that clears everyone of any further responsibility and slows down the pace of discovery in paleontology.

That’s why the LRT is here. To provide tested taxon lists for more focused studies.

References
de Witte & Frechkop, 1955. The Brain of Micropotamogale ruwenzorii (De Witte and Frechkop, 1955). Zeitschrift für Säugetierkunde 51:193-204.
Du Chaillu P 1860. Descriptions of mammals from equatorial Africa. Proceedings of the Boston Society of Natural History, 7, 358–369.
Everson KM, et al (3 co-authors) 2016. Multiple Loci and Complete Taxonomic Sampling Resolve the Phylogeny and Biogeographic History of Tenrecs (Mammalia: Tenrecidae) and Reveal Higher Speciation Rates in Madagascar’s Humid Forests. Syst. Biol. 65(5):890–909, 2016
Gohar et al. (7 co-authors) 2021. A new protocetid whale offers clues to biogeography and feeding ecology in early cetacean evolution. Proceedings of the Royal Society B https://doi.org/10.1098/rspb.2021.1368
de Lacepede BGE 1799. Discours d’ouverture et de clôture du cours d’histoire naturelle : donné dans le Muséum national d’Histoire naturelle, l’an VII de la République, et tableaux méthodiques des mammifères et des oiseaux, Paris.
Miart St G 1871 On Hemicentetes, a new genus of Insetivora, with some additional remarks on teh osteology of that order. Proceedings of the Zoological Society of London for 1871:58-79.
Marshall CD and Eisenberg JF 1996. Hemicentetes semispinosus. Mammalian Species 541: 1-4. Online here.
Nicoll M 1985. The biology of the giant otter shrew *Potamogale velox*. National Geographic Society Research Reports, 21: 331-337.
Sahni A and Mishr VP 1972. A new species of Protocetus (Cetacea) from the Middle Eocene of Kutch, western India. Palaentology 15(3):490–495.
Thewissen JGM and Bajpai S 2009. New skeletal material of Andrewsiphius and Kutchicetus, two Eocene cetaceans from India. Journal of Palaentology 83(5):635–663.

wiki/Andrewsiphius
wiki/Hemicentetes
wiki/Tenrec
wiki/Phiomicetus
wiki/Potamogale
wiki/Micropotamogale
reptileevolution.com/hemicentetes
reptileevolution.com/potamogale
ncbi.nlm.nih.gov/pmc/articles/PMC4841219/