Helpless and able newborn mammals

I’m going to crowd source this one,
but I think I covered all the bases here. In this subset of the large reptile tree (LRT, 1165 taxa) I’ve divided placental mammals born helpless (blue) from mammals born able to walk, swim and see (pink). I’ll need your help if there are any exceptions, like pangolins, that I missed one way or the other. Fossils are colorized based on phylogenetic bracketing.

Figure 1. Newborn mammals are born either helpless, like humans, or able to keep up with their mother, like horses. I think I located the split correctly here. Let me know I missed a few.

Figure 1. Newborn mammals are born either helpless, like humans, or able to keep up with their mother, like horses. I think I located the split correctly here. Let me know I missed a few. Fossil taxa are colored based on phylogenetic bracketing. 

Marine taxa need to be ready to go from the first minute.
Apparently so do the large plant-eaters ( including ant and copepod eaters), beginning with long-legged former tree shrew, Onychodectes.

Dens and nests
are associated with basal mammals, like us. Not so much with the derived herbivores (and anteaters) of the plains and forests. All of them get milk from their mothers before they start to dine on meat, plants, ants and copepods. Some of them have to keep up with here. Some of them have to keep up with her underwater.

BTW
there also seems to be a behavioral node at Maelestes in which succeeding taxa are all leaving the trees for good. Of course, that also happens exceptionally with the various mole and aquatic clades in more basal mammals.

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Where are the auditory bullae in desmostylians?

A reader wondered about
tympanic (auditory) bullae (ear container bones) in desmostylians. Then I wondered, too. All whales are famous for having them. Nobody talks about them in desmostylans. So what gives? Here are the data:

Short answer:
apparently bullae are easily knocked off and/or ignored during the process of fossilization and extraction, both in mysticetes and desmostylians. Some examples follow:

Gray whale (Eschrichtius)
Bullae were present, but somehow got knocked off when it came time to draw the diagram (Fig. 1).

Figure 1. Gray whale (genus: Eschrichtius) in which bullae were present, but omitted from a palate diagram.

Figure 1. Gray whale (genus: Eschrichtius) in which bullae were present, but omitted from a palate diagram.

Cornwallius (a pre-desmostylian cambaythere) — overlooked bulla, called a ‘mass’ in the text.

Figure 3. The pre-desmostylian Cornwallius. Here the tympanic bulla (bright green) was considered "a mass" in the text and otherwise was not labeled.

Figure 3. The pre-desmostylian Cornwallius. Here the tympanic bulla (bright green) was considered “a mass” in the text and otherwise not labeled.

Neoparadoxia (basal desmostylian)
Here you can see the depression that receives the bullae, but the bullae became missing at some stage in the process.

Figure 3. Palate of Neoparadoxia, a basal desmostylian, apparently missing the tympanic bullae (ear bones).

Figure 3. Palate of Neoparadoxia, a basal desmostylian, apparently missing the tympanic bullae (ear bones). Note the ear canal bones extending laterally, as in the hippo (figure 6).

Desmostylus, a derived desmostylian close to right whales
Same here. Bulla not published. Depression for the reception still present.

Figure 4. Desmostylus with missing bullae replaced in the empty spots left behind.

Figure 4. Desmostylus with missing bullae replaced in the empty spots left behind. Skull is obviously distorted and missing a big part of the cranium.

Caperea, a basal right whale
Here’s an odd one. Not sure what happened to the bulla in ventral view. They seem to appear in occiput view.

Figure 6. Caperea, a basal right whale, apparently missing the bullae in palate view that it had in occipital view.

Figure 5. Caperea, a basal right whale, apparently missing the bullae in palate view that it had in occipital view. If not, please advise.

Hippopotamus
This goes back somewhat on the tree, but hippos are in the lineage of baleen whales in the LRT and their auditory bones are present.

Figure 7. Hippopotamus with auditory meatus (ear canal) in green, bulla (ear bone container bones) in yellow.

Figure 6. Hippopotamus with auditory meatus (ear canal) in green, bulla (ear bone container bones) in yellow.

Ear bones compared
Baleen whale bullae greatly resemble toothed whale bullae. It’s true. Based on phylogeny, we’ll have to call this convergence. So is the loss of teeth in the rostrum of the sperm whale and blue whale. Convergence happens, but let’s keep an eye out for those bullae, now that we know what should be there.

Bipedal Cretaceous lizard tracks

These are the oldest lizard tracks in the world…
(if you don’t consider Rotodactylus (Early Triassic) strictly a ‘lizard’ (= squamate). One rotodactylid trackmaker, Cosesaurus, is a tiny lepidosaur).
Figure 1. Bipedal lizard tracks from South Korea in situ.

Figure 1. Bipedal lizard tracks from South Korea in situ. They are tiny.

From the abstract
“Four heteropod lizard trackways discovered in the Hasandong Formation (Aptian-early Albian), South Korea assigned to Sauripes hadongensis, n. ichnogen., n. ichnosp., which represents the oldest lizard tracks in the world. Most tracks are pes tracks that are very small. The pes tracks show “typical” lizard morphology as having curved digit imprints that progressively increase in length from digits I to IV, a smaller digit V that is separated from the other digits by a large interdigital angle. The manus track shows a different morphology from the pes. The predominant pes tracks, the long stride length of pes, narrow trackway width, digitigrade manus and pes prints, and anteriorly oriented long axis of the fourth pedal digit indicate that these trackways were made by lizards running bipedally, suggesting that bipedality was possible early in lizard evolution.”
Actually, the lizard was not running.
Typically in running tracks the prints are very far apart and these tracks are sometimes left toe to right heel.
Figure 2. Original and new tracings of the bipedal lizard tracks from South Korea. PILs are added,

Figure 2. Original and new tracings of the bipedal lizard tracks from South Korea. PILs are added. Manual digit 4 and 5 appear to have shifted.

 The authors did not venture who made the tracks.
They reported, “based on the palaeobiogeographic distribution of facultative extant families, the lizard that produced S. hadongensis tracks could well have been a member of an extinct family or stem members of Iguania, which was present in the Early Cretaceous.”
Actually the closest match among tested taxa
is with Eichstaettisaurus (Fig. 1), a basal member in the lineage of snakes. And this clade is close to the origin of geckos. ReptileEvolutiion.com and the large reptile tree would have been good resources for the authors to use. Lots of lizard pedes were illustrated and scored there.
Figure 3. Originally pictured as a generic lizard (below), here Eichstattsaurus scaled to the track size walks upright.

Figure 3. Originally imagined  as a generic lizard (below), here Eichstattsaurus matched and scaled to the track size walks upright.

 Based on a phylogenetic analysis of the tracks
the closest match in the LRT is with Eichstaettisaurus, so a slightly larger relative made them. Distinct from the skeletal taxon, the trackmaker had a longer p2.1 than 2.1 and pedal digit 1 was quite short. Otherwise a good match in all other regards.
So why walk bipedally?
It was walking, not running, so escape from predation can be ruled out. Elevating the upper torso and head, like a cobra, can be intimidating to rivals, or just offer a better view over local plant life. This sort of flexibility could have helped them get into the trees and then to move to higher branches.
References
Lee H-J, Lee Y-N, Fiorillo AR &  LÃ J-C 2018. Lizards ran bipedally 110 million years ago. Scientific Reports 8: 2617. doi:10.1038/s41598-018-20809-z

Cornwallius: not a desmostylian, an ancestor to desmostylians

These taxa
are part of the a recent review of mysticete (baleen whale) ancestors you can read about here, here and here.

Cornwallius sookensis (originally Desmostylus sookensis, Hay 1923, Cornwall 1922; Beatty 2006a, b; Early Oligocene, 25 mya; Fig. 1) was originally and traditionally considered a desmostylian (Fig. 3). Here it nests with Cambaytherium (Fig. 2), both basal to anthracobunids like Janjucetus. These taxa have a narrow skull and a deep jugal beneath the squamosal. The nares are anterior, rather than dorsal in location.

Figure 1. Adult Cornwallius look more like desmostylians. Juveniles look more like anthracobunids. Both are descendant taxa.

Figure 1. Adult Cornwallius look more like desmostylians. Juveniles look more like anthracobunids. Both are descendant taxa.

Note the resemblance
(lack of a downturned snout) on the juvenile to Cambaytherium (above). Apparently, neotony produces a straights-snout anthracobunid. Otherwise it evolves to the tusky, droop-snout, desmostylian grade.

Figure 2. Cambaytherium with a an alternate rostrum reversing taphonomic shifts.

Figure 2. Cambaytherium with a an alternate rostrum reversing apparent taphonomic shifts.

Beatty 2006
produced the following cladogram (Fig. 3) in which desmostylians are derived from the Moeritherium/Elephas clade. In the large reptile tree (LRT, 1163 taxa) cambaytheres and desmostylians arise from mesonychids and hippos.

Figure 2. From Beatty 2006b, a phylogeny of desmostylians derived from moeritherium, an aquatic relative of elephants and sirenians (manatees). Actually desmostylians arise from cambaytheres and anthracobunids, arising from hippos and mesonychids. 

Figure 3. From Beatty 2006b, a phylogeny of desmostylians derived from moeritherium, an aquatic relative of elephants and sirenians (manatees). Actually desmostylians arise from cambaytheres and anthracobunids, arising from hippos and mesonychids.

References
Beatty, BL 2006a. Rediscovered specimens of Cornwallius (Mammalia, Desmostylia) from Vancouver Island, British Columbia, Canada. Vertebrate Palaeontology. 1(1):1–6.
Beatty, BL 2006b. Specimens of Cornwallius sookensis (Desmostylia, Mammalia) from Unalaska Island, Alaska. Journal of Vertebrate Paleontology. 26(3):785–87.
Cooper LN, Seiffert ER, Clementz M, Madar SI, Bajpai S, Hussain ST, Thewissen JGM 2014. Anthracobunids from the Middle Eocene of India and Pakistan Are Stem Perissodactyls. PLoS ONE. 9 (10): e109232. doi:10.1371/journal.pone.0109232. PMID 25295875.
Cornwall IE 1922. Notes on the Sooke Formation, Vancouver Island, B.C. Canadian Field Naturalist. 36:121–23.
Hay OP 1923. Characteristics of sundry fossil vertebrates. Pan-American Geologist. 39:101–120.
Kumar K 1991. Anthracobune aijiensis nov. sp. (Mammalia: Proboscidea) from the Subathu Formation, Eocene from NW Himalaya, India”. Geobios. 24 (2): 221–39. doi:10.1016/s0016-6995(91)80010-w. OCLC 4656806310.
Rose, KD et al. (8 other authors) 2014. Early Eocene fossils suggest that the mammalian order Perissodactyla originated in India. Nature Communications. 5 (5570). doi:10.1038/ncomms6570.

wiki/Cambaytherium
wiki/Cornwallius

Mystacodon: See how far they’ll go to ‘find’ a mysticete ancestor

According to Wikipedia
Mystacodon (Lambert et al. 2017) is a genus of toothed mysticete from the Late Eocene Yumaque Formation of Peru. It is the earliest known member of the Mysticeti, and the second confirmed Eocene mysticete.” Here (Fig. 1) you can compare it to the smaller and more primitive (because it has a bigger pelvis) Maiacetus, to scale. Mystacodon is no mysticete. It’s what a tenrec/odontocete becomes when it gets good at swimming, but not as good as Zeuglodon, which has an even smaller pelvis. We looked at the origin of mysticetes among desmostylians earlier here, here and here. It was first reported here, last October, perhaps too late for the manuscript submission publishing schedule. Even so, whale experts have omitted, overlooked or ignored desmostylians in their quest for mysticete ancestors, and this is what happens.

This is what happens with taxon exclusion.
You get a ‘by default’ nesting, like nesting turtles and Vancleavea with archosaurs or Tetraceratops with therapsids. It also reminds me of when David Hone and Sterling Nesbitt bent over backward to find a mandibular fenestra and an antorbital fossa on pterosaurs in a desperate attempt to prove an invalid hypothesis.

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

FIgure 1. My, what big teeth you have! This toothy whale with a tiny pelvis is Mystcodon, originally promoted as the earliest known mysticete (baleen whale). Note the size and placement of the teeth matching Maiacetus.

And the whale authors got all the publicity they wanted
in this Guardian article with illustrations. Here is a quote from the article:

“Fossil hunters say they have unearthed a missing link in the evolution of baleen whales after digging up the remains of a creature thought to have lived more than 36 million years ago.

The whales, known as mysticeti, sport a bristling collection of sieve-like plates known as baleen that they use to filter water for food. Species include the enormous blue whale, the gray whale and the humpback whale.

But while baleen whales are known to have shared a common ancestor with toothed whales, which are the other major group of modern whales, the path by which the creatures emerged has been somewhat hazily understood. Now researchers say they have discovered the oldest known cousin of modern baleen whales, offering unprecedented insights into their evolution.

“This [split in the family tree] has been dated to about 38 or 39m years ago,” said Olivier Lambert, co-author of the research from the Royal Belgian Institute of Natural Sciences. “The whale we discovered here has been dated to 36.4 [million years ago], so it is only two to three million years younger than this presumed origin.”

From Nature.com:
“This is the fossil that we’ve been waiting for,” says Nick Pyenson, a palaeontologist at the Smithsonian National Museum of Natural History in Washington DC. 

“To determine where M. selenensis fit in the whale family tree, the researchers compared characteristics such as the shape of its skull and pelvic bone to those of other fossil whales. The creature’s flat snout resembles that of modern baleen whales. But its pelvic bone fit more with ancestral whales, complete with areas where the leg bones would typically slot in, says Lambert. “So, we think that this animal still had tiny legs protruding from the body.”

“Lambert and his colleagues think that M. selenensis might have sucked up its prey from the ocean floor. This wasn’t unusual, however, because baleen-whale ancestors around that time sported a wide variety of dental and feeding mechanisms. “There’s big toothed things, there’s little toothed things and there’s toothless things, all at once,” says Uhen. But by around 23 million years ago, all the whales in this group had baleen, and “all these toothy things go away”, he says.”

Mystacodon has a wide flat triangular rostrum…
so does Physeter, the sperm whale (Fig. 3).

Figure 3. Physeter (sperm whale) skull. Note the low, flat, triangular toothless rostrum.

Figure 3. Physeter (sperm whale) skull. Note the low, flat, triangular toothless rostrum.

Workers:
Examine all possible candidates. Don’t exclude relevant taxa. Mystacodon sheds no light on the origin of baleen whales—but it does shed light on the origin of odontocetes.

References
Lambert, O. et al. (seven co-authors) 2017. Earliest Mysticete from the Late Eocene of Peru Sheds New Light on the Origin of Baleen Whales. Current Biology 27:1535–1541.e2 doi:10.1016/j.cub.2017.04.026.

 

Aetiocetus: it’s supposed to be a baleen whale ancestor

This is going to be another paleo story about taxon exclusion.
Earlier we looked at paleoworkers trying to nest turtles among diapsids and pterosaurs among archosaurs… but this only happens when more closely related taxa are overlooked or omitted. In the case of the toothed archaic whale, Aetiocetus (Fig. 1), it sure looks like a good candidate for baleen ancestry. The palate was wide, triangular and flat. Unfortunately there are better candidates that were overlooked. Details below.

Figure 1. Three species attributed to Aetiocetus. Other workers considere these basal to baleen whales, but they don't include tenrecs and desmostylians in their analyses.

Figure 1. Three species attributed to Aetiocetus. Other workers considere these basal to baleen whales, but they don’t include tenrecs and desmostylians in their analyses. The teeth of A. polydentatus are simple cones, as in modern toothed whales.

Wikipedia reports:
Aetiocetus is a genus of extinct basal mysticete (baleen whale (late Oligocene, 30 mya). The large reptile tree (LRT, 1161 taxa) nests it with other toothed whales, far from mysticetes. Some traits that distinguish Aetiocetus from other toothed whales include:

  1. the nostrils of the whale had migrated further back on the skull than seen in archaeocetes, but not so far as in modern whales.
  2. no more than three small denticles on the anterior and posterior margins of the posterior upper teeth.
  3. postcanine teeth heterodont.
  4. The base of the rostrum, or snout, of the whale, is greater than 170% of the width of the occipital condyles where the skull meets the neck.
  5. notch by the internal nostrils formed of the palatine, pterygoid, and vomer bones
  6. coronoid process of the dentary well developed
  7. zygomatic arch is expanded anteriorly and posteriorly but is narrow at the middle.
  8. mandibular symphysis not fused.
  9. descending process of the maxilla becomes a toothless plate below the orbit.
  10. wide rostrum

According to Wikipedia,
all these features are functionally related to filter-feeding with baleen and are hallmarks of the Mysticeti. The presence of teeth seems ‘paradoxical’ to these workers. Unfortunately, this hypothetical relationship is recovered only in the absence of desmostylians. 

According to the National Library of Medicine
“All bones possess larger or smaller foramina (openings) for the entrance of the nourishing blood-vessels.”

According to Marx et al. 2016:
“Aetiocetids have previously been proposed as the most basal mysticetes to possess baleen, the key adaptation of modern whales. More specifically, the widespread occurrence of palatal nutrient foramina (in Aetiocetus, Fucaia and Morawanocetus), which in extant mysticetes supply the baleen rack, has been used to infer the existence of an incipient baleen structure between or just lingual to the teeth (Deméré and Berta, 2008; Deméré et al., 2008). While such an interpretation is possible, it also remains untested: just as the origin of feathers in non-avian dinosaurs does not mark the beginnings of flight, so the appearance of palatal foramina in mysticetes need not indicate the presence of baleen. Instead, the foramina of aetiocetids could, for example, have supplied its immediate predecessor – namely, well-developed gums, the presence of which is indicated both by the strongly emergent teeth of early mysticetes (Deméré and Berta, 2008; Fitzgerald, 2010) and, possibly, the largely unworn incisor of NMV P252567.”

Baleen was not found in any specimen of Aetiocetus. 
The presence of baleen is inferred from the presence of nutrient foramina. If so, then baleen had two convergent origins and Aetiocetus represents a dead end, leaving no modern descendants. If nutrient foramina only fed the skin and other tissues that lined the jaws, then no baleen was present.

Baleen WAS found
in the basal mysticete, Miocaperea (Bisconti 2012, skull 1 meter long; Miocene). Traditionally whale workers consider taxa like Caperea and Miocaperea highly derived because desmostylians are not included in their analyses. By contrast, the LRT finds these to be basal mysticetes, Caperea for right whales and Miocaperea for all other mysticetes. Most studies nest Caperea with right whales (clade: Balaenoidea; Demere et al. 2005, Churchill et al. 2012, Ekdale et al. 2011. Marx 2010, did not. All wrongly assume Odontoceti as the outgroup.

Figure 4. The caption for this photo is: "Brian Beatty measuring the jaws of one of our toothed mysticetes. Photo by R. Boessenecker."

Figure 2. The caption for this photo is: “Brian Beatty measuring the jaws of one of our toothed mysticetes. Photo by R. Boessenecker.” This was the traditional view of mysticete origins prior to the addition of desmostylians to the LRT.

The image above
is from  the CCNHM blogsite and the caption for the photo is: “Brian Beatty measuring the jaws of one of our toothed mysticetes. Photo by R. Boessenecker.” Perhaps unknown to Professor Beatty, this is true only in the absence of desmostylians from phylogenetic analysis, an easy mistake to make prior to the entry of desmostylians to the LRT. Various authors have been bending over backwards trying to discover the origin of mysticetes among toothed whales. But they cannot be discovered there. Mysticetes arise from desmostylians, taxa studied by Professor Beatty, but the mysticete connection was not realized.

And that, again demonstrates the value of the LRT,
which permits taxa that have never been tested together to nest together. Taxon inclusion solves every problem in paleontology.

Chronology
This is always a problem due to the rarity of fossils, typically (but not always) recovered as late survivors long after initial radiations. These are taxa recovered by the LRT in the lineage of mysticetes.

  1. Mesonyx: Paleocene or earlier
  2. Ocepeia: Paleocene
  3. Cambaytherium: Eocene
  4. Anthracobune: Eocene
  5. Desmostylus: Oligocene
  6. Cetotherium: Oligocene
  7. Miocaperea: Late Miocene
  8. Caperea and others: Recent

Characters that separate aetiocetids from cetotheres:

  1. Skull shorter than half the presacral length
  2. Snout not constricted
  3. Premaxilla/maxilla notch less than 25º
  4. Naris angle 30-90º but dorsal
  5. Nasals subequal to frontals
  6. Orbit shape in lateral view at least half longer than tall
  7. Frontals without posterior processes
  8. Postparietals angled from the dorsal plane
  9. Tabulars absent
  10. Squamosal descending process at right angle
  11. Frontals and parietals both fused
  12. Occiput far posterior to quadrate articulation
  13. Opisthotics descend
  14. Vomernasal (or other anterior palatal opening) separate from choanae (internal narial opening) by maxilla
  15. Premaxilla teeth present and robust
  16. Last maxillary tooth present and anterior to orbit
  17. Some cervical neural spines taller than centra
  18. 10th caudal length not > chevron depth
  19. Interclavicle/sternal elements present
  20. Scapula not robust
  21. Manual digit 1 present

Interesting tidbits
The coronoid process becomes larger in two tested cetotheres, but not the basal Cetotherium. You wouldn’t think baleen whales would need a tall coronoid process (used for biting), and most don’t have one, but Tokharia and Yamatocetus do.

It only takes the deletion of a few desmostylians to nest baleen whales with toothed whales, due to the large number of similar traits (which is why we call them all ‘whales’. Conversely it only takes the deletion of a few archaic whales to nest odontocetes with baleen whales, as I discovered through testing these options.

For more heretical desmostylian information,
click here.

References
Bisconti M 2012. Comparative osteology and phylogenetic relationships of Miocaperea pulchra, the first fossil pygmy right whale genus and species (Cetacea, Mysticeti, Neobalaenidae). Zoological Journal of the Linnean Society 166: 876-911.
Buchholtz E 2010. Vertebral and rib anatomy in Caperea marginata: Implications for evolutionary patterning of the mammalian vertebral column. Marine Mammal Science 27: 382-397.
Churchill M, Berta A, Deméré TA 2012. The systematics of right whales (Mysticeti: Balaenidae). Marine Mammal Science 28: 497-521.
Deméré TA, Berta A and McGowen MR 2005. The taxonomic and evolutionary history of modern balaenopteroid mysticetes. Journal of Mammalian Evolution 12: 99-143.
Ekdale E G, Berta A and Deméré TA 2011. The comparative osteology of the petrotympanic complex (ear region) of extant baleen whales (Cetacea: Mysticeti). PLoS ONE 6:1-42.
Emlong D 1966. A new archaic cetacean from the Oligocene of Northwest Oregon. Bulletin of the Museum of Natural History, University of Oregon. 3: 1–51.
Fitzgerald EMG 2012. Possible neobalaenid from the Miocene of Australia implies a long evolutionary history for the pygmy right whale Caperea marginata (Cetacea, Mysticeti). Journal of Vertebrate Paleontology 32:976-980.
Marx FG 2011. The more the merrier? A large cladistic analysis of mysticetes, and comments on the transition from teeth to baleen. Journal of Mammalian Evolution 18:77-100.
Marx et al. 2016. Suction feeding preceded filtering in baleen whale evolution. Memoirs of Museum Victoria 75: 71–82.
Van Valen L 1968. Monophyly or diphyly in the origin of whales. Evolution. 22 (1):37–41.

wiki/Aetiocetus

Evolution of the other baleen whales according to the LRT

Earlier we looked at the evolution of right whales from desmostylians like Desmostylus.  Today we’ll look at the other baleen whales: the rorquals, gray whales and cetotheres (Fig. 1), as recovered by the large gamut analysis of the large reptile tree (LRT, 1161 taxa, see subset below Fig. 3).

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

Figure 1. Rorqual evolution from desmostylians, Neoparadoxia, the RBCM specimen of Behemotops, Miocaperea, Eschrichtius and Cetotherium, not to scale. No thumb on these flippers.

Distinct from traditional studies
the LRT (subset, Fig. 2) nests Caperea (the pygmy right whale) with right whales, not cetotheres (Fig. 1) … and not with Miocaperea (Fig. 1)  the tiny Miocene baleen whale.

Caudal #15
In figure 1 caudal 15 is dotted (Fig. 1), highlighting the terminal caudal in the desmostylian Neoparadoxia and its ancestors, the mysticete whales. In cetotheres caudal 15 remains the terminal caudal. In other baleen whales more caudal vertebrae are added. By homology the terminal caudal #15 is just beyond the coccyx in these taxa. As reported yesterday, it’s not that the tail lengthened, although it did, its that the pelvis shrank and the coccyx became much more robust in these taxa.

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 2 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 (see figure 1). 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 longer lumbar region in non-right whales.

A longer lumbar region
is present in these whales compared to right whales and Desmostylus shown yesterday.

Figure 2. Subset of the LRT focusing on the mesonyx/mysticete clade showing the split between right whales and all other mysticetes.

Figure 3. Subset of the LRT focusing on the mesonyx/mysticete clade showing the split between right whales and all other mysticetes.

It’s worth noting again
that most workers and traditional studies nest baleen whales with the broad-billed toothed archaeocete Aetiocetus… but that’s only in the absence of tenrecs and desmostylians that separate odontocetes from mysticetes in the LRT.

Figure 5. Traditional cladogram that nests baleen whales with toothed whales in the absence of tenrecs and desmostylians.

Figure 4. Traditional cladogram that nests baleen whales with toothed whales in the absence of tenrecs and desmostylians.

Let’s see if paleontologists will follow this suggestion
to include these taxa in future analyses. The present record of avoiding key taxa in other controversial clades, like turtles and pterosaurs, does not bode well.