A giant Eocene whale from Ukraine

Davydenko et al. 2021
report the discovery of new giant basilosaurid from Ukraine.

From the abstract:
“The earliest fully aquatic cetaceans arose during the Middle Eocene; however, the earliest stage of their divergence is obscure. Here, we provide a detailed redescription of an unusual early cetacean, “Platyosphys einori”, from the Late Eocene of Ukraine (37.8–35.8 million years ago), with new data on its body size, skeletal microanatomy and suggestions on phylogenetic relationships.”

By contrast, in the large reptile tree (LRT, 1793+ taxa) the earliest stage of ‘their divergence’ (mysticetes and odontocetes) extends back to tiny tree shrews in the Jurassic. Contra public and professional opinion, whale divergence is not obscure. Taxon exclusion hampers the Davydenko et al. study.

Figure 1. Cladogram from Davydenko et al. 2021 showing how they nested Playosphys einori. See figure 2 for their proposed mysticetes (with teeth!)

Figure 1. Cladogram from Davydenko et al. 2021 showing how they nested Playosphys einori. See figure 2 for their proposed mysticetes (with teeth!)

Unfortunately the authors presented an outdated cladogram
that considered the former clade ‘Cetacea’ monophyletic. Their paper perpetuates an invalid hypothesis of interrelationships (Figs. 1,2) that omits the ancestors of mysticetes: desmostylians, anthracubunids, hippos, mesonychids and oreodonts. They also omit the ancestors of pakicetids: tenrecs and anagalids.

Figure 2. Portion of the cladogram from figure 1 enlarged and rotated. Llancetus and kin are not mysticete ancestors when more taxa, like Behemotops, are included in the analysis.

Figure 2. Portion of the cladogram from figure 1 enlarged and rotated. Llancetus and kin are not mysticete ancestors when more taxa, like Behemotops, are included in the analysis.

Sadly,
whale workers continue to perpetuate the myth that whales are monophyletic. That was invalidated several years ago here by simply adding taxa.


References
Davydenko S, Shevchenko T, Ryabokon T. et al. 2021. A Giant Eocene Whale from Ukraine Uncovers Early Cetacean Adaptations to the Fully Aquatic Life. Evol Biol (2021). https://doi.org/10.1007/s11692-020-09524-8

researchgate.net/publication/328388746_The_triple_origin_of_whales

reptileevolution.com/reptile-tree.htm

SVP abstracts 18: Palatal foramina and the origin of baleen in mysticetes

Peredo and Pyenson 2020 discuss
the origin of baleen in mysticetes by looking at palatal foramina.

“Baleen whales (mysticetes) filter-feed using specialized keratinous plates, called baleen, to sieve large quantities of prey laden water. Baleen represents a wholly novel integumentary structure, with no apparent homologous structure in any living animal. The origins of baleen, and filter-feeding in whales, have been the topic of much debate. In particular, the lack of osteological correlates for baleen makes it unclear which (if any) stem mysticetes first had keratinous structures for filter feeding.”

The origin of baleen in whales is found in traditionally overlooked nearly toothless desmostylians like Desmostylus (Fig. 2) and Behemotops (Fig. 3), taxa nesting basal to mysticetes in the large reptile tree (LRT, 1751+ taxa; subset Fig. 1).

Figure 3. The oreodont-mesonychid-hippo-desmoystlian-mysticete clade subset of the LRT

Figure 1. The oreodont-mesonychid-hippo-desmoystlian-mysticete clade subset of the LRT

“One potential osteological correlate are palatal foramina and sulci: structures in the roof of the mouth that may vascularize the baleen plates.”

Peredo and Pyenson are “Pulling a Larry Martin” by looking for a few ‘key’ traits rather than running a phylogenetic analysis of all traits without excluding pertinent taxa, such as Desmostylus and Behemotops.

“Palatal foramina are present and well developed in extant and fossil crown mysticetes and are preserved in some stem mysticetes as well. Here, we report the presence of numerous and well-developed palatal foramina in non-filter-feeding cetaceans, including crown and stem odontocetes and in stem cetaceans (so-called archaeocetes).”

Peredo and Pyenson are excluding pertinent taxa.

“Additionally, we observe the presence of palatal foramina in 61 observed species of terrestrial artiodactyls.”

Peredo and Pyenson are excluding pertinent taxa. No artiodactyls are basal to any whales in the LRT. Hippos are not artiodactyls in the LRT. Toothed whales arise from tenrecs and anagalids.

Figure 1. Taxa in the lineage of right whales include Desmostylus, Caperea and Eubalaena. The tiny bit of jugal posterior to the orbit (in cyan) is found in all baleen whales tested so far. The frontals over the eyes are just roofing the eyeballs in Desmostylus, much wider in Caperea and much, much longer in Eubalaena.

Figure 2. Taxa in the lineage of right whales include Desmostylus, Caperea and Eubalaena. The tiny bit of jugal posterior to the orbit (in cyan) is found in all baleen whales tested so far. The frontals over the eyes are just roofing the eyeballs in Desmostylus, much wider in Caperea and much, much longer in Eubalaena.

The Peredo and Pyenson abstract continues:
“CT scanning demonstrates consistent internal morphology across all observed palatal foramina, suggesting that the palatal foramina observed in extant mysticetes are homologous to those of terrestrial artiodactyls.”

This sounds like cherry-picking taxa. Perhaps palatal foramina are typical of non-arboreal mammals? What do tenrec and desmostylian foramina look like?

Figure 1. Rorqual evolution from desmostylians, Neoparadoxia, the RBCM specimen of Behemotops, Miocaperea, Eschrichtius and Cetotherium, not to scale.

Figure 3. Rorqual evolution from desmostylians, Neoparadoxia, the RBCM specimen of Behemotops, Miocaperea, Eschrichtius and Cetotherium, not to scale.

The Peredo and Pyenson abstract continues:
“The presence of palatal foramina in non-filter-feeding whales (odontocetes and archaeocetes) and in terrestrial artiodactyls suggest that the structures are more probably associated with an elaborate gingiva or other oral tissue and are alone not reliable osteological correlates for the presence of baleen in fossils.”

Next time, just add pertinent taxa and run the analysis… then see what turns up. The origin of baleen in whales was answered here in 2016. ResearchGate.net has an unpublished paper to read on the triple origin of whales here.


References
Peredo CM and Pyenson N 2020. Palatal foramina in stem whales and terrestrial artiodactyls obfuscate their potential for inferring baleen in stem mysticetes. SVP abstracts 2020.

wiki/Baleen_whale

SVP abstracts 7: Coombs follows the traditional whale origin myth

Coombs 2020 studied whale skulls
using a traditional, but recently invalidated phylogeny. She did not understand the diphyly of the former clade ‘Cetacea’.

From the Coombs abstract:
“The extant clades of whales, Odontoceti (toothed whales) and Mysticeti (baleen whales), diverged ~39 Ma.”

According to the large reptile tree (LRT, 1749+ taxa) that divergence occurred way back when whale ancestors were still tree shrews. A tiny taxon, Anagale (Fig. 1; Late Cretaceous, 75-71mya) is near their last common ancestor.

Figure 1. We are very fortunate to have several of these basal placental taxa still living with us, as chronologically long-lived taxa. Starting with the extant Didelphis at the base of the Theria, phylogenetic miniaturization gave us the smaller Monodelphis domestics and the even smaller M. sores and M. kunsi, which gave rise to the larger Nandinia at the base of the Carnivora, Tupaia, at the base of the expanded Glires, Ptilocercus at the base of the expanded Archonta, and Maelestes at the base of the tenrecs + whales and the Condylarthra, aka the rest of the mammals.

Figure 1. We are very fortunate to have several of these basal placental taxa still living with us, as chronologically long-lived taxa. Starting with the extant Didelphis at the base of the Theria, phylogenetic miniaturization gave us the smaller Monodelphis domestics and the even smaller M. sores and M. kunsi, which gave rise to the larger Nandinia at the base of the Carnivora, Tupaia, at the base of the expanded Glires, Ptilocercus at the base of the expanded Archonta, and the Condylarthra, aka the rest of the mammals.

Continuing from the Coombs abstract:
“Odontocetes evolved high-frequency echolocation and cranial asymmetry, while mysticetes evolved larger masses and filter feeding.”

Actually odontocete ancestors, represented by extant tenrecs, developed echolocation and cranial asymmetry, by the Paleocene 65mya.

Mysticete ancestors did not develop filter feeding until the Oligocene, 34-23mya at the earliest. Mystacodon (Fig. 2; 36mya) was considered the earliest baleen whale, but this toothy whale nests with the odontocete clade.

FIgure 1. This toothy whale with a tiny pelvis is Mystcodon, originally promoted as the earliest known mysticete (baleen whale).

FIgure 2. This toothy whale with a tiny pelvis is Mystcodon, originally promoted as the earliest known mysticete (baleen whale).

Continuing from the Coombs abstract:
“Despite an excellent fossil record and unique morphology, there has been little quantitative study of shape evolution spanning cetacean diversity.”

Before making that statement, Coombs should add taxa to start with a valid phylogeny, lacking at present. Ancestors to both whale clades (Fig. 3) have been traditionally overlooked due to taxon exclusion.

“To quantify morphological disparity and evolutionary rate in cranial shape and to identify ecological correlates of shape variation across Cetacea, I gathered 3D scans of specimens representing 84 living (72 odontocetes, 12 mysticetes) and 72 Eocene to Pliocene fossil (45 odontocetes, 17 mysticetes, 10 archaeocetes) cetaceans. I then digitized 123 landmarks and 64 curves on these scans and conducted high-dimensional geometric morphometric and macroevolutionary analyses within a phylogenetic framework.”

The Coombs phylogenetic framework is fatally flawed due to taxon exclusion. Adding pertinent taxa will solve this problem.

Figure 4. Subset of the LRT focusing on the odontocetes and their ancestors.

Figure 3. Subset of the LRT focusing on the odontocetes and their ancestors.

Continuing from the Coombs abstract:
“The largest component of cranial variation (PC1 = 39.9%) reflects a posterior shift in the nares and separates odontocete and mysticete modes of cranial telescoping. Rostrum length is the major component of variation on PC2 (20.7%) with dolicocephalic [having a long skull] (e.g., Pontoporia blainvillei) and brachycephalic [having a short skull] (e.g., Kogia sima) crania representing the extremes.”

Figure 3. The oreodont-mesonychid-hippo-desmoystlian-mysticete clade subset of the LRT

Figure 4. The oreodont-mesonychid-hippo-desmoystlian-mysticete clade subset of the LRT

Continuing from the Coombs abstract:
“Cranial asymmetry in archaeocetes is high in the rostrum, squamosal, jugal, and orbit, possibly reflecting preservational deformation. In odontocetes, it is highest in the naso-facial region. Mysticetes show levels of asymmetry similar to terrestrial artiodactyls.”

In other words: essentially no asymmetry. Why? Because mysticetes and odontocetes had different ancestors. Artiodactyls had nothing to do with whales ever since the LRT pulled hippos out of the artiodactyls and into the mesonychids (Fig. 4).

Figure 1. Taxa in the lineage of right whales include Desmostylus, Caperea and Eubalaena. The tiny bit of jugal posterior to the orbit (in cyan) is found in all baleen whales tested so far. The frontals over the eyes are just roofing the eyeballs in Desmostylus, much wider in Caperea and much, much longer in Eubalaena.

Figure 5. Taxa in the lineage of right whales include Desmostylus, Caperea and Eubalaena. The tiny bit of jugal posterior to the orbit (in cyan) is found in all baleen whales tested so far. The frontals over the eyes are just roofing the eyeballs in Desmostylus, much wider in Caperea and much, much longer in Eubalaena.

Continuing from the Coombs abstract:
“Significant rate shifts in asymmetry are observed in the stem odontocetes Xenorophidae (∼30 Ma), Physeteroidea (∼27 Ma), Squalodelphinidae (~27 Ma), and Monodontidae (~7 Ma). Rapid evolution of both cranial shape and asymmetry in cetaceans occurred in the Middle-Late Oligocene and peaks in the Middle Late Miocene, largely due to subclade-specific diversification of rostrum and facial morphology.”

Coombs’ results, no matter how carefully measured, are incomplete because they are not recovered within a valid phylogenetic context. Add pertinent taxa to resolve this issue.


References
Coombs E 2020. Cranial morphology in whales: A study spanning the evolutionary history and diversity of the Cetacean skull. SVP abstracts 2020.

3x a tiny mammal tail evolved flukes

I found the following results
recovered from the large reptile tree (LRT, 1709+ taxa) to be particularly fascinating given the apparent illogic of developing a robust swimming tail with flukes from an tiny ancestral tail barely able to act as a ‘flap’.

You might remember
earlier we looked at the reversal of teeth in the lineage of odontocetes (toothed whales), reversing step-by-step to a simple cone from the typical complex, multi-cusped molar of a tree shrew.

Likewise in toothed whales, but not exactly correlated,
the tail also experienced a reversal, becoming longer and more robust after derivation from the tiny speck of a tail in tenrec ancestors.

With that introduction
here are the three times the tail has elongated and grown horizontal flukes in placental mammals:

1 – Manatee tail evolution
The terrestrial Moeritherium-like ancestors of today’s aquatic manatees and dugongs had a long torso and tiny tail, distinctly unlike the robust tail with flukes found in today’s Sirenia (Figs. 1–3). Prorastomus (Fig. 2) is a transitional taxon having a more robust tail. Procavia, the living hyrax, has an even smaller tail than these taxa and is more primitive.

Figure 1. Moeritherium skeleton. Note the tiny, slender tail.

Figure 1. Moeritherium skeleton. Note the tiny, slender tail.

 

Figure 1. Prorastomus is a pro-sirenian with legs. All four feet remain unknown.

Figure 2. Prorastomus is a pro-sirenian with legs. All four feet remain unknown.

The splitting in two of ancestrally longer caudal vertebrae (or the increase in caudal number while reducing each caudal vertebral length) appears to be the method employed by evolution to create a longer, more robust tail in manatees and their ancestors.

Figure 2. Dusisiren, a manatee sister has a robust tail and presumably, flukes.

Figure 3. Dusisiren, a manatee sister has a robust tail and presumably, flukes.

2 – Mysticete tail evolution
Neoparadoxia (Fig. 4), a desmostylian ancestor of modern toothless (baleen) whales, likewise had a tiny tail, similar to that of its hippo-like ancestors, useless for propulsion.

Figure 1. GIF animation of the Neoparadoxia (original image from Barnes 2013). It seems illogical that the tiny tail of a desmostylian like this would ever become the giant tail of a mysticete, while the giant hind limbs disappear into the torso, but phylogenetic analysis recovers just such a scenario. Many long-jawed desmostylians are known from cranial material only and these are likely to be those that had large tails and smaller hind limbs.

Figure 4. GIF animation of the Neoparadoxia (original image from Barnes 2013). It seems illogical that the tiny tail of a desmostylian like this would ever become the giant tail of a mysticete, while the giant hind limbs disappear into the torso, but phylogenetic analysis recovers just such a scenario. Many long-jawed desmostylians are known from cranial material only and these are likely to be those that had large tails and smaller hind limbs.

The re-elongation of the tail in mysticete ancestors is not (yet) documented in transitional fossils, which is one factor in keeping this bit of evolution a secret, even from whale experts. Nevertheless, the rest of the anatomy is enough to nest these two former clades together into one clade. Here the number of tail vertebrae does not increase so much as the robust morphology of each one (Figs. 5–7).

Figure 1. Taxa in the lineage of right whales include Desmostylus, Caperea and Eubalaena. The tiny bit of jugal posterior to the orbit (in cyan) is found in all baleen whales tested so far. The frontals over the eyes are just roofing the eyeballs in Desmostylus, much wider in Caperea and much, much longer in Eubalaena.

Figure 5. Taxa in the lineage of right whales include Desmostylus, Caperea and Eubalaena. The tiny bit of jugal posterior to the orbit (in cyan) is found in all baleen whales tested so far. The frontals over the eyes are just roofing the eyeballs in Desmostylus, much wider in Caperea and much, much longer in Eubalaena.

The apparent length of the tail is enhanced by the disappearance of the hind limbs and the pelvis in mysticetes and other completely aquatic mammals.

Figure 2. Caperea, the pygmy right whale, is a much smaller sister to Eubalaena. Only the skeleton with the ribs angled back fits the stranded in vivo specimen and the skull is a better fit when it is slightly larger.

Figure 6. Caperea, the pygmy right whale, is a much smaller sister to Eubalaena. Only the skeleton with the ribs angled back fits the stranded in vivo specimen and the skull is a better fit when it is slightly larger.

Behemotops and Miocaperera fossils (Fig. 7) do not presently preserve tail vertebrae. These transitional taxa are the ones most likely to transition to reduced legs and a robust tail. It is also apparent that these taxa are ancestral to rorquals, while Desmostylus (Fig. 5) is ancestral to right whales… which means 4x a tiny mammal tail evolved flukes.

Figure 1. Rorqual evolution from desmostylians, Neoparadoxia, the RBCM specimen of Behemotops, Miocaperea, Eschrichtius and Cetotherium, not to scale.

Figure 7. Rorqual evolution from desmostylians, Neoparadoxia, the RBCM specimen of Behemotops, Miocaperea, Eschrichtius and Cetotherium, not to scale.

3 – Odontocete tail evolution
The elongation of the torso and tail in the ancestors of odontocete (toothed) whales is better preserved in the fossil and extant record.

Figure 2. The short-tailed tenrec, Hemicentetes. Other than size and tail length, this taxon shares a long list of traits with the basal whale, Maiacetus in figure 1.

Figure 8 The short-tailed tenrec, Hemicentetes. Other than size and tail length, this taxon shares a long list of traits with the basal whale, Maiacetus in figure 1.

Here, starting with the tiny tail found in Hemicentetes (Fig. 8), the tail elongates in Indohyus and Leptictidium (Fig. 9) to become the swimming organ used in Pakicetus and fully aquatic toothed whales.

Figure 1. Odontoceti (toothed whale) origin and evolution. Here Anagale, Andrewsarchus, Sinonyx, Hemicentetes, Tenrec Indohyus and Leptictidium precede Pakicetus. Maiacetus and Orcinus are aquatic odontocetes.

Figure 9. Odontoceti (toothed whale) origin and evolution. Here Anagale, Andrewsarchus, Sinonyx, Hemicentetes, Tenrec Indohyus and Leptictidium precede Pakicetus. Maiacetus and Orcinus are aquatic odontocetes.

Since a long, robust tail is already in the gene pool,
a placental mammal can redevelop a long, robust tail from not much of one.


References
.researchgate.net/The_triple_origin_of_whales
wiki/Evolution_of_sirenians

Phylogeny of Desmostylia: Matsui and Tsuihiji 2019

Matsui and Tsuihiji 2019 bring us their views
on the phylogeny of taxa within their Desmostylia, an order of large aquatic (Pacific rim) mammals, best known from the early Oligocene (31mya) to the late Miocene (7.25mya). Traditionally there are relatively few taxa in the clade Desmostylia (Neoparadoxia (Fig. 2), Paleoparadoxia, Behemotops (Fig. 2), Desmostylus (Fig. 3) and a few others not as well represented in the fossil record.

Unfortunately the authors’ views
are too restricted with too few taxa under consideration. Desmostylians are not the extinct taxa Matsui and Tsuihiji think they are when more taxa are included (Fig. 1).

From their abstract:
“Background.
Desmostylia is a clade of extinct aquatic mammals with no living members.”

False. Although this is traditional thinking in the large reptile tree (LRT, 1638+ taxa; subset Fig. 1) living desmostylians include mysticete (baleen) whales. Their ancestors include oreodonts, mesonychids, hippos, cambaytheres and anthracobunids.

Figure 3. the Merycoidodon cladogram includes hippos, whales and a number of extinct taxa.

Figure 1. The Merycoidodon cladogram includes hippos, whales and a number of extinct taxa. Traditional desmostylians are in medium blue here.

 

The abstract continues:
“Today, this clade is considered belonging to either Afrotheria or Perissodactyla.”

Their figure 1 shows desmosytlians arising from either: (a) Equus, the horse, in the Perissodactyla hypothesis; (b) Elephas, the elephant, in the Afrotheria hypothesis, or (c) Procavia, the hyrax, in their Paenungulatomorpha hypothesis. In other words, the authors have no idea. Genomic studies deliver false positives like Afrotheria. and you can’t used genomic studies of deep time fossils. In the LRT, which uses traits, desmostylians arise from mesonychids, hippos and anthracobunids as we learned earlier here.

“In the currently-accepted taxonomic scheme, Desmostylia includes two families, 10
to 12 genera, and 1314 species. There have been relatively few phylogenetic analyses
published on desmostylian interrelationship compared to other vertebrate taxa, and
two main, alternative phylogenetic hypotheses have been proposed in previous studies.
One major problem with those previous studies is that the numbers of characters and
OTUs were small.”

So Matsui and Tsuihiji, are studying the details without understanding the big picture… which could affect the details. Better to have a firm foundation built, then afterwards add whatever decorations to your structure.

Figure 1. Rorqual evolution from desmostylians, Neoparadoxia, the RBCM specimen of Behemotops, Miocaperea, Eschrichtius and Cetotherium, not to scale.

Figure 2. Rorqual evolution from desmostylians, Neoparadoxia, the RBCM specimen of Behemotops, Miocaperea, Eschrichtius and Cetotherium, not to scale.

The abstract continues:
“Methods.

In this study, we analyzed the phylogenetic interrelationship of Desmostylia

based on a new data matrix that includes larger numbers of characters and taxa than in
any previous studies. The new data matrix was compiled mainly based on data matrices
of previous studies and included three outgroups and 13 desmostylian ingroup taxa.
Analyses were carried out using five kinds of parsimonious methods.”

Their three outgroups were: [1] Anthracobune, [2] Pezosiren + Moeritherium and [3] all three. Again, they are playing ‘pin the tail on the donkey‘ when the actual outgroups are available online (Fig. 1). No blind guesswork is necessary.

Figure 1. Taxa in the lineage of right whales include Desmostylus, Caperea and Eubalaena. The tiny bit of jugal posterior to the orbit (in cyan) is found in all baleen whales tested so far. The frontals over the eyes are just roofing the eyeballs in Desmostylus, much wider in Caperea and much, much longer in Eubalaena.

Figure 3. Taxa in the lineage of right whales include Desmostylus, Caperea and Eubalaena. The tiny bit of jugal posterior to the orbit (in cyan) is found in all baleen whales tested so far. The frontals over the eyes are just roofing the eyeballs in Desmostylus, much wider in Caperea and much, much longer in Eubalaena.

The abstract continues:
“Results.

Strict consensus trees of the most parsimonious topologies obtained in all

analyses supported the monophyly of Desmostylidae and paraphyly of traditional
Paleoparadoxiidae. Based on these results, we propose phylogenetic definitions of the
clades Desmostylidae and Paleoparadoxiidae based on common ancestry.”

That’s fine, but incomplete. This is another classic case of knowing so much about a few taxa, while knowing nothing about their ancestors, sisters and descendants, all based on taxon exclusion. That’s why the LRT is here. The LRT is the first instrument to report that the clade Cetacea was diphyletic. Members of the Odontoceti (toothed whales) are not related to members of the Mysticeti (baleen whales), contra traditional studies that exclude pertinent taxa.

Some workers insist
that I add characters to the LRT, but as you can see, adding more traits to the LRT would not reveal the ancestors, sisters or descendants of the Desmostylia. Only more taxa solve this problem. More taxa create greater resolution and nest all enigmas. More characters do not and cannot do that, so enough with that lame request.

If you want to add more or different traits
to your more focused studies, by all means, do so! But keep that taxon list complete. Let the LRT be your guide.


References
Matsui and Tsuihiji 2019. The phylogeny of desmostylians revisited: proposal of new clades based on robust phylogenetic hypotheses. PeerJ:e7430 http://doi.org/10.7717/peerj.7430

Gatesy’s blueprint for whale origins omits foundation taxa

Gatesy et al. 2012
attempted to provide “A phylogenetic blueprint for a modern whale.”

Unfortunately
Gatesy et al. did not realize that whales are diphyletic (or triphyletic). Gatesy et al. failed to include anagalid, elephant shrew and tenrec taxa basal to odontocetes and failed to include desmostylian taxa basal to mysticetes.

Not much else needs to be said.
Taxon exclusion, once again, is the fatal flaw.

References
Gatesy J et al. (7 co-authors) 2012. A phylogenetic blueprint for a modern whale. Molecular Phylogenetics and Evolution. PDF online.

Maiabalaena: a new mysticete, this time lacking baleen

A new paper by Peredo et al. 2018
describes a new early Oligocene mysticete: “Maiabalaena had neither teeth nor baleen—it represents a surprising intermediate stage between modern filter-feeding whales and their toothed ancestors.”

The new taxon is:
Maiabalaena nesbittae (Peredo, Pyenson, Marshall and Uhen 2018; USNM 314627).

Peredo et al. remind us:
“The functional transition from teeth to baleen in mysticetes has remained enigmatic because baleen decays rapidly and leaves osteological correlates with unclear homology.”

Actually that’s not the problem.
Peredo et al. and other whale workers continue to follow the invalid hypothesis of a monophyletic Cetacea. They believe in false precept of a ‘toothed mysticete’. They refuse to include desmostylians, hippos, mesonychids, tenrecs, and other pertinent taxa in their phylogenetic analyses. Adding these taxa recovers two origins for living whales from distinct quadrupedal semi-aquatic taxa in the large reptile tree (LRT, 1354 taxa). Desmostylians already lack most of their teeth (Fig. 4) and that explains tooth loss in mysticetes.

Figure 1. Maiabalaena is a close relative of Yamatocetus in the LRT, not a transitional taxon to archaeocete whales.

Figure 1. Maiabalaena is a close relative of Yamatocetus in the LRT, not a transitional taxon to archaeocete whales. The tip of the jaw was not in the original lateral view, so it is added here.

Peredo et al. report, The oldest direct evidence for fossil baleen is 25 million years younger than the oldest stem mysticetes (36 Ma). Previous hypotheses for the origin of baleen are inconsistent with the morphology and phylogenetic position of Maiabalaena. The absence of both teeth and baleen in Maiabalaena is consistent with recent evidence that the evolutionary loss of teeth and origin of baleen are decoupled evolutionary transformations, each with a separate morphological and genetic basis. Understanding these macroevolutionary patterns in baleen whales is akin to other macroevolutionary transformations in tetrapods such as scales to feathers in birds.”

Except that scales don’t evolve into feathers in birds.
And these authors will never understand the macroevolutionary patterns in baleen whales without adding pertinent taxa (listed above) that are currently routinely omitted.

With more LRT taxa, the other explanation for baleen loss is: 
baleen was lost in derived mysticetes like Maiabalaena… that is, if Maiabalaena actually lacked baleen, which I doubt without much evidence other than the enormous gape in the mouth of Maiabalaena (Fig.1).

Figure 2. A selection of cetotheres, including Maiabalaena, to scale.

Figure 2. A selection of cetotheres, desmostylians and other whales, including Maiabalaena, to scale.

In the LRT
Maiabalaena is closely related to Yamatocetus (Fig. 2), both unrelated to toothed whales. Taxon exclusion renders the Peredo et al. study basically useless.

Figure 3. Cladogram from Peredo et al. 2018. Colors added to show members of the odontocete/ archaoecete clade (red tint) and the mysticete clade (cyan tint) in the LRT.

Figure 3. Cladogram from Peredo et al. 2018. Colors added to show members of the odontocete/ archaoecete clade (red tint) and the mysticete clade (cyan tint) in the LRT. Lacking here are taxa that split these two clades in the LRT where cetotheres are derived taxa, despite their extinct status.

Presented once again,
here (Fig. 4) are a few mysticete ancestors. Cetotheres, with their giant flat heads, are derived myisticetes, not basal forms.

Figure 1. Rorqual evolution from desmostylians, Neoparadoxia, the RBCM specimen of Behemotops, Miocaperea, Eschrichtius and Cetotherium, not to scale.

Figure 4. Rorqual evolution from desmostylians, Neoparadoxia, the RBCM specimen of Behemotops, Miocaperea, Eschrichtius and Cetotherium, not to scale.

PhD candidate Carlos Peredo appeared on NPR’s Science Friday podcast
here. I commented Feb. 2, 2019 below that YouTube video, repeated below:

“Maiabalaena, is a highly derived flat-headed baleen whale that has lost its baleen according to a phylogenetic analysis that includes more taxa. The actual ancestors of baleen whales were desmostylians, hippos, mesonychids and oreodonts, not related to Pakicetus. Toothed whales evolved separately from Pakicetus, which was a large aquatic tenrec, which are small mammals alive today on the island of Madagascar. Tenrecs hunt in packs (pods) and some use echolocation helped by their asymmetric skulls.”

References
Peredo et al., 2018. Tooth Loss Precedes the Origin of Baleen in Whales. Current Biology (2018), https://doi.org/10.1016/j.cub.2018.10.047

Morenocetus: a small Early Miocene right whale ancestor

Another taxon to consider
in our search for the ancestors of right whales. This one is small enough to have a skull similar in size to that of the earlier (Oligocene) desmostylian, Desmostylus (Fig. 1).

Figure 1. Morenocetus and related right whale skulls, Eubaelana and xx to scale along with the Oligocene ancestor in the LRT, Desmostylus.

Figure 1. Morenocetus and related right whale skulls, Eubaelana and Balaenella, to scale along with the Oligocene ancestor in the LRT, Desmostylus. Note the size of the Morenocetus skull is quite similar to that of the earlier Desmostylus, which already has reduced hind limbs. Only the cranial portion of the Morenocetus skull is known and was shown in Buono et al. 2012. All skull drawings are from Buono et al. 2012. They were set to the same scale here.

Buono et al. 2012 report,
“The earliest recognized balaenid is the early Miocene Morenocetus parvus Cabrera, 1926 from Argentina. M. parvus was originally briefly described from two incomplete crania, a mandible and some cervical vertebrae collected from the lower Miocene Gaiman Formation of Patagonia. Since then it has not been revised, thus remaining a frequently cited yet enigmatic fossil cetacean with great potential for shedding light on the early history of crown Mysticeti. Here we provide a detailed morphological description of this taxon and revisit its phylogenetic position. The phylogenetic analysis recovered the middle Miocene Peripolocetus as the earliest diverging balaenid, and Morenocetus as the sister taxon of all other balaenids.The analysis of cranial and periotic morphology of Morenocetus suggest that some of the specialized morphological traits of modern balaenids were acquired by the early Miocene and have remained essentially unchanged up to the present.”

Figure 1. Taxa in the lineage of right whales include Desmostylus, Caperea and Eubalaena. The tiny bit of jugal posterior to the orbit (in cyan) is found in all baleen whales tested so far. The frontals over the eyes are just roofing the eyeballs in Desmostylus, much wider in Caperea and much, much longer in Eubalaena.

Figure 2. Taxa in the lineage of right whales include Desmostylus, Caperea and Eubalaena. The tiny bit of jugal posterior to the orbit (in cyan) is found in all baleen whales tested so far. The frontals over the eyes are just roofing the eyeballs in Desmostylus, much wider in Caperea and much, much longer in Eubalaena.

Wikipedia reports, from Buono et al. 2012:
“Morenocetus is distinguished from more derived balaenids in the narrow exposure of the squamosal lateral to the exoccipital, a short supraorbital process of the frontal, straight lateral edges of the supraoccipital, and a postorbital process of the frontal oriented posteriorly. It can be distinguished from the only other Miocene balaenid, Peripolocetus in having a dorsoventrally expanded zygomatic process of the squamosal. The body length of Morenocetus is estimated at 17 to 18 feet (5.2 to 5.5 m), and the rostrum is moderately arched dorsoventrally in contrast to crown Balaenidae.”

Buono et al. 2012
did not include nearly toothless desmostylians in their taxon list when they analyzed ‘cetacean’ relationships, but continued the myth of the monophyletic clade ‘Cetacea’ due this taxon exclusion issue.

A paper describing the triple origin of whales
can be accessed here and here.

References
Buono MR, Fernández MS, Cozzuol MA, Cuitiño JI and Fitzgerald EMG 2017. The early Miocene balaenid Morenocetus parvus from Patagonia (Argentina) and the evolution of right whales. PeerJ 5:e4148; DOI 10.7717/peerj.4148
Demere T and Pyenson N 2015. Filling the Miocene ‘Balaenid Gap’ – the previously engimatic Peripolocetus vexillifer Kellogg, 1931 is a stem balaenid (Cetacea: Mysticeti) from the Middle Miocene (Langhian) of California, USA. Journal of Vertebrate Paleontology 35 (Supplement): 115A.
El Adli JJ, Deméré TA and Boessenecker RW 2014. Herpetocetus morrowi (Cetacea: Mysticeti), a new species of diminutive baleen whale from the Upper Pliocene (Piacenzian) of California, USA, with observations on the evolution and relationships of the Cetotheriidae. Zoological Journal of the Linnean Society 170 (2): 400–466. doi:10.1111/zoj.12108.

wiki/Peripolocetus
wiki/Morenocetus

 

Llanocetus: not a ‘baleen whale with teeth and gums’

Hailed in the popular press
(see below) as a ‘baleen whale with teeth and gums’, Llanocetus denticrenatus (Mitchell 1989; Fordyce and Marx 2018; 8m in estimated length; 34 mya), nests in the large reptile tree (LRT, 1320 taxa) with archaeocete (toothed) whales, not with mysticetes (baleen whales).

Fordyce and Marx described Llanocetus
from a virtually complete skull (Fig. 1) as “the second oldest mysticete known.” Their phylogenetic analysis nested Llanocetus with Mystacodon, which they describe as “the oldest mysticete,” but earlier the LRT nested it with archaeocete toothed whales, too.

Figure 1. Llanocetus, hailed as a baleen whale with teeth and gums, is just a large archaeocete.

Figure 1. Llanocetus, hailed as a baleen whale with teeth and gums, is just a large archaeocete.

According to Fordyce and Marx, “The broad rostrum has widely spaced teeth marked with dental abrasion and attrition, suggesting biting and occlusal shearing.” Such traits are unexpected in a filter-feeder.

Figure 1. (above) Zygorhiza kochi from George Mason University website, likely captured from Kellogg 1936.

Figure 2. (above) Zygorhiza kochi from George Mason University website, likely captured from Kellogg 1936. To make the jaws fit and teeth occlude the mandible had to be reduced and the cranium had to tilted down posteriorly.

Fordyce and Marx attempt to force-fit their new taxon into the Mysticeti
when they report, “As in extant mysticetes, the palate bears many sulci, commonly interpreted as osteological correlates of baleen. Unexpectedly, these sulci converge on the upper alveoli, suggesting a peri-dental blood supply to well-developed gums, rather than to inter-alveolar racks of baleen. We interpret Llanocetus as a raptorial or suction feeder, revealing that whales evolved gigantism well before the emergence of filter feeding.”

No mention of desmostylians here…

Figure 1. Rorqual evolution from desmostylians, Neoparadoxia, the RBCM specimen of Behemotops, Miocaperea, Eschrichtius and Cetotherium, not to scale.

Figure 3. Rorqual evolution from desmostylians, Neoparadoxia, the RBCM specimen of Behemotops, Miocaperea, Eschrichtius and Cetotherium, not to scale. It is worthwhile noting the similarities shown between Cetotherium and Ilanocetus. Such convergences are the source of Fordyce and Marx’s hypotheses.

Fordyce and Marx conclude in their abstract,
“This scenario differs strikingly from that proposed for odontocetes, whose defining adaptation-echolocation-was present even in their earliest representatives.” 

Unfortunately,
the authorse have no idea that those ‘earliest representatives’ of odontocetes are represented today by tenrecs that also echo-locate and travel in pods, as we learned earlier here.

Once again,
taxon exclusion is to blame for the earlier mistakes. Fordyce and Marx refuse to test desmostylians in their analyses, similar to pterosaur workers who refuse to test tritosaur lepidosaurs, and turtle workers who refuse to test small horned pareiasaurs. That’s why the wide gamut taxon list of the LRT comes in so handy. You don’t have to guess or force-fit any taxa… just let the software and the taxon list do your work for you.

No wonder whale workers are not letting
my papers on whale, turtle and pterosaur origins be published. 

References
Fordyce RE and Marx FG 2018. Gigantism precedes filter feeding in baleen whale evolution. Current Biology 28(10):1670–1676.

wiki/Llanocetus

https://www.techtimes.com/articles/227549/20180512/34-million-year-old-skull-from-antarctica-reveals-baleen-whales-had-teeth-and-gums.htm

SVP 2018: New Mammalodon relative with marine worm bores

Shipps, Peredo and Pyenson 2018 report
on a Late Oligocene mammalodontid, the first from the Northern Hemisphere. “The skull and teeth of this specimen bear boreholes from bone-eating Osedax worms, providing valuable information on the taphonomy of the specimen. Critically, this specimen preserves intact ear bones and several teeth.”

Osedax is marine worm.
According to Wikipedia, “The worms bore into the bones of whale carcasses to reach enclosed lipids, on which they rely for sustenance.”

Figue 1. Mammalodon nests within the clade Anthracobune basal to desmostylians and mysticetes.

Figue 1. Mammalodon nests within the clade Anthracobune basal to desmostylians and mysticetes.

Mammalodon (Fig. 1) is indeed in the lineage of mysticete whales, but several nodes distant (Fig. 2) in the large reptile tree. It is related to Janjucetus and Anthracobune, basal to desmostylians, not far from hippos. Desmostylians are also found along the Pacific rim, so this appearance of an ancestor in Washington state is expected. All are mesonychids, not ungulates.

Figure 2. Subset of the LRT focusing on mysticetes, including Sitsqwayk, and their predecessors.

Figure 2. Subset of the LRT focusing on mysticetes, including Sitsqwayk, and their predecessors.

References
Shipps BK, Peredo CM and Pyenson ND 2018. An unexpected Northerner with burrowed bones: a new mammalodontid (Mysticeti) from the Pacific Northwest with Osedax bores provides insight into Oligocene marine taphonomy and mysticete evolution. SVP abstracts.

wiki/Osedax
wiki/Janjucetus
wiki/Mammalodon
wiki/Anthracobune