Timeline of desmostylian systematics

Few placental clades are as misunderstood as the Desmostylia.
This was well documented by Domning, Ray and McKenna 1986 with their review of desmostylian origin (Figs 1, 3) and interrelation studies (abbreviated below). This timeline provides insight into the phylogenetic struggles paleontologists suffered over this clade in the pre-cladistic, pre-software era.

Figure 1. Isanacetus compared to scale with desmostylian sisters recovered in the LRT. Balaeonoptera (at bottom) is much reduced.

Unfortunately, this struggle continues in 2022
due to… (drum roll, please) …taxon exclusion. You’ll either weep or chuckle with bemusement as the best PhDs of their respective eras kept their blinders on, spending decades struggling for an answer that wasn’t going to be found where they were looking. Apparently most workers were hesitant to look somewhere other than where others had looked for a solution to the 134-year-old desmostylian problem. Note how professors through the decades kept beating around the same bush without success or resolution, not imagining they should be looking elsewhere.

Abridged from Domning, Ray and McKenna 1986:
“O.C. Marsh (1888) referred Desmostylus to the Sirenia.”

“Yoshiwara and Iwasaki (1902), believed their find [a desmostylian] to be some sort of proboscidean, based in part on a letter from H.F. Osborn. Although Osborn had “informed” them that the skull belonged to a proboscidean, Yoshiwara and Iwasaki demonstrated that it was not like deinotheres or elephantids and therefore would have to represent a branch from the primitive proboscideans, near the origin of that order from among the other ungulates. They also mentioned some similarities to Sirenia.”

“Hay (1915), followed by Matsumoto (1918), placed the Desmostylidae in the Sirenia, although
he emphasized that the Desmostylidae were very different from other (true) sirenians.”

“Abel (1922:381; 1923) abandoned his view of proboscidean affinities of Desmostylus in
favor of a bizarre notion that it belonged to the mammalian subclass Allotheria (= Multituberculata).”

Although misguided and wrong, at least Abel was expanding his gamut.

“Sickenberg (1938), however, argued strongly against a desmostylian-sirenian relationship.”

Ijiri (1939) considered Desmostylus to be an ungulate “in the broadest sense” but not a monotreme, multituberculate, marsupial, or sirenian.”

Minkoff (1976) suggested that desmostylians should be placed with the Amblypoda rather
than the Paenungulata.

Amblypoda are basalmost condylarths = Pantodontids and Phenacodontids in the LRT. Like others before, Minkoff was likewise playing darts in the dark by suggesting and guessing.

Domning, Ray and McKenna 1986 correctly compared desmostylians with hippos,
but ironically did not permit hippos to enter analysis. The authors made no mention of the mysticeti, mesonychids, or oreodonts, which turn out to be related to desmostylians when more taxa are added to analysis, as in the large reptile tree (LRT, 2061 taxa, subset Fig 2).

Figure 2. Subset of the LRT focusing on condylarth placentals including desmostylians nesting basal to mysticetes, the one clade desmostylian workers universally and historically seem to avoid.

But wait, there’s more…
Workers often and correctly associate desmostylians with anthracobunids, but once again, fall into the same proboscidean sticky trap.

Domning, Ray and McKenna 1986 considered Anthracobune a proboscidean,
so their phylogenetic problems extended beyond desmostylians. In the LRT (Fig 2) anthracobunids nest between hippos and desmostylians, far from elephants.

From Domning, Ray and McKenna 1986:
“Manning’s identification of Anthracobune as a Moeritherium-Vike animal was also generously made known to R.M. West, who was the first to publish on the matter (West, 1980:518; 1983). West placed Anthracobune in the Moeritheriidae.”

“During the long interval from 1940 to 1980, Anthracobune (with “Pilgrimella”) had masqueraded as an artiodactyl (Pilgrim, 1940; Gingerich, 1977; Coombs and Coombs, 1977; and most other authors), a perissodactyl (Coombs and Coombs, 1977:303; 1979), and a phenacodontid condylarth (Van Valen, 1978, fig. 3). Wells and Gingerich (1983) assigned it to a new family Anthracobunidae within the Proboscidea, and (based on an examination of the specimens of Behemotops reported herein) suggested that the Desmostylia, as well as the Moeritheriidae and the Sirenia, may be derived from anthracobunids. The fact that Anthracobune occurs in southern Asia, rather than in Africa, was doubtless a major cause of its long neglect in discussions of the phylogenetic origin of proboscideans and their possible affinities to the desmostylians.”

Lessson 1: Let your software and a wide gamut taxon list
tell you which taxa to include, not the other way around. That would be considered akin to gerrymandering or cherry-picking. And it’s okay to make mistakes along the way. Look at the professionals of the past that kept their blinders on despite their lack of confidence in their results (see above). None were ostracized or lost their paycheck or place in science.

Lesson 2: Don’t depend on dental traits at first,
not until your wide gamut cladogram is fully resolved and major clade interrelationships are confidently known from substantial skulls and skeletons. Then you can drop in your partial taxa and dental taxa with greater confidence.

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

If you are at all prescient, or a long time reader,
you’ll know what comes next: Pterosaurs. Turtles. Snakes. Reptiles. Placoderms. Creodonts. Bats. Catfish. Diapsids. These are all taxa that find a good, secure (= fully resolved) home in the LRT, something they cannot presently find in university textbooks. Desmoystlians are also firmly nested in the LRT, but still an enigma otherwise.

Remember, all professors were once students
eager to please their own professors by parroting paradigms. All academic authors know they have to satisfy anonymous referees (= sometimes jealous and self-serving academic competitors). Both systems discourage discovery and heresy. In academia consensus rules (see timeline above). It always has. And it always will. That means it comes down to politics, not science. That’s why it sometimes takes an outsider to pull the curtain back on enigma taxa to give them a home based on the scientific method with complete transparency and falsifiability …and to take the occasional barb for the trouble of doing so without payment or tangible reward.

References
Domning DP, Ray CE and McKenna MC 1986. Two New Oligocene Desmostylians and a Discussion of Tethytherian Systematics. Smithsonian Contributions to Paleobiology 59:56pp.
Peters D unpublished. The triple origin of whales. PDF on ResearchGate.org

Phosphatherium enters the LRT twice, but not with elephants

Phosphatherium escuillei (Gheerbrant, Sudre and Cappetta 1996; Late Paleocene; 10cm skull length; Fig 1) has been a traditional elephant ancestor since its discovery (Gheerbrant, Sudre and Cappetta 1996) and rediscovery as a second specimen (Gheerbrant E et al. 2005; Gheerbrant 2009) assigned to the same genus and species.

After testing
in the large reptile tree (LRT, 2062 taxa, subset Fig 3) both new Phosphatherium specimens nest together, but derived from the more plesiomorphic, Ectocion ralstonensis (Fig 1), a taxon omitted by prior authors. That means Phosphaterium is less of an elephant ancestor than is the omitted, more plesiomorphic Late Paleocene taxon, Ectocion ralstonensis (Cope 1882 a, e; Granger 1915; Thewissen 1990). “A Palaeocene proboscidean from Morocco” got published in Nature in 2005. I’m guessing, “An Ectocion descendant leaving no descendants” would not have gotten published in Nature. Ya gotta do, whatcha gotta do in paleo.

In the LRT taxa closer to elephants include
Procavia, the hyrax, basal to sirenians. These two taxa and their descendants have a single pair of incisor tusks at most.

Figure 1. Above: Phosphatheirum. Middle: Ectocion. Below: Eritherium parts applied to a ghosted image of Ectocion.

Here two Phosphatherium skulls
(Fig 1) are not the same species, but share more traits with each other than with other taxa.

Figure 2. Fossils in the elephant + manatee clade including Phosphatherium Palaeomastodon, Moeritherium, Ectocion, Notostylops, Radinskya, Diadiaphorus, Procavia and the chalicothere, Anisodon.

Phosphatherium was close to the ancestry of elephants
(Fig 2) but several taxa were closer, despite the big bone appearance of Phosphatherium, convergent with elephants.

Figure 3. Subset of the LRT focusing on terrestrial placentals including Phosphatherium nesting in a clade between hyraxes and manatees + elephants.

Gheerbrant 2009 described the partial remains of Eritherium azzouzorum,
(Fig 1) as “the oldest and most primitive elephant relative” at 60mya, 5 million years earlier than Phosphatherium. The partial remains consist of a palate (maxilla + jugals) and teeth, plus paired frontals and nasals. This is too little to fragmentary for the LRT, but note how well the pieces fit into a coeval Ectocion ralstonensis bauplan (Fig 1). Here the subhead, “Also a hyrax and manatee relative” would have been appropriate. The LRT lists elephant ancestors back to the Cambrian, just like every other included taxon.

Gheerbrant 2005 wrote:
“We report here significant new material belonging to the oldest and most primitive known Proboscidean, Phosphatherium escuilliei Gheerbrant, Sudre & Cappetta, 1996, from the early Eocene of the Ouled Abdoun phosphatic basin, Morocco. This material permits the first reconstruction of the skull and most of upper and lower dentition of Phosphatherium escuilliei.”

This second specimen (Fig. 1) does bring much needed data to this genus.

“The species, which is one of the oldest and most primitive known representatives of modern orders of ungulates, becomes one of the best known among them. Its dentition shows a noticeable dental variability, which is interpreted, at least provisionally, to be intraspecific.

Elephants don’t have diverse post-incisor tooth morphology like more primitive taxa do.

“The skull of Phosphatherium escuilliei is very primitive in many respects. It is long with an elongated facial part and a narrow rostrum. The toothrow does not extend posteriorly beyond the middle of the skull. The nasals are long and located anteriorly (i.e. nasal fossa not retracted). There is no contact between the premaxilla and frontal. There is a strong postorbital constriction and a distinct postorbital process on the frontal. The zygomatic arches are noticeably expanded laterally.

That lateral expansion is not shared with Ectocion, sirenians or elephants.

“The sagittal and nuchal crests are strong. The external auditory meatus is open ventrally. The braincase is strongly compressed laterally”.

In other words, the brain was not wide or large.

“Some primitive features of the dentition are also noticeable.“

That means distinct incisors, canines, premolars and molars.

“However, Phosphatherium escuilliei displays several strikingly advanced features, especially proboscidean and tethytherian features. A cladistic study of 129 features of Phosphatherium escuilliei supports the monophyly of Proboscidea and the inclusion of Phosphatherium within the order.

The LRT does not confirm the inclusion of Phosphatherium within the clade of elephants.

“The most significant Proboscidean synapomorphies found in Phosphatherium are: 1) the well developed zygomatic process of the maxillary which contributes significantly to the ventral border of the orbit and to the zygomatic arch; 2) the relatively large size of the pars mastoidea of the periotic; and 3) the hypoconulid in a labial position (a state unique to Proboscidea).“

The Gheerbrant et al. 2005 taxon list
included Ectocion (but which species?) representing the suprageneric taxon ‘Phenacodontidae’. The authors mistakenly included the unrelated suprageneric clades, Embrithopoda, Anthracobunidae and Desmostylia, erroneously following current textbooks and traditions. The authors employ Perissodactylia, a related clade, but again it is used as a suprageneric taxon. That’s always dangerous and rife with bias and cherry-picking. The authors employ a long list of dental traits not used by the LRT.

By contrast
the LRT employs no suprageneric taxa and no chimaera taxa, only specimens and species. That’s why both Phosphatherium taxa (Fig. 1) entered the LRT separately. In the LRT there is no cherry-picking of data from suprageneric taxa to suit an author preference.

The omission of Ectocion ralstonensis from prior analyses needs to be repaired in future studies on elephant origins.

The Phosphatherium authors employed taxa not tested in the LRT.
One: Late Paleocene Phenacolophus is a mandible + teeth taxon.

Two: Late Paleocene Minchenella (= Conolophus, preoccupied by an iguana) was described by Domning, Ray and McKenna 1986 as “a suitable candidate to be the common ancestor of both the Desmostylia and the Proboscidea” based on a molar cusp. The LRT separates these two clades based on more complete skeletons. More on that issue tomorrow.

References
Domning DP, Ray CE and McKenna MC 1986. Two New Oligocene Desmostylians and a Discussion of Tethytherian Systematics. Smithsonian Contributions to Paleobiology 59:56pp.
Gheerbrant E, Sudre J and Cappetta H 1996. A Palaeocene proboscidean from Morocco. Nature. 383 (6595): 68–71.
Gheerbrant E et al. 2005. Nouvelles données sur Phosphatherium escuilliei (Mammalia, Proboscidea) de l’Éocène inférieur du Maroc, apports à la phylogénie des Proboscidea et des ongulés lophodontes. Geodiversitas 27 (2), 2005, pp. 239-333.
Gheerbrant E 2009. Paleocene emergence of elephant relatives and the rapid radiation of African ungulates. Proc Natl Acad Sci USA. 106(26): 10717–10721.

wiki/Phosphatherium
wiki/Notostylops
wiki/Ectocion

Some trilobites are not extinct

Here is where I go ahead and state the unaccepted obvious:
Horseshoe crabs (Figs 1–4) are living trilobites (Figs 1–4). Everyone already senses this at some basic level. This is especially so for that clade of Early Cambrian trilobites sporting a long, sharp telson (= axial spine) rather than a more traditional wide pygidium. That telson-sporting clade is represented here by Pseudosaukianda (Figs 1, 3).

The University of Houston
describes how most universities think about horseshoe crabs and trilobites: “The nearest thing to a trilobite today is the horseshoe crab with a very similar exoskeleton. Trilobites lasted over 300-million years and finally died out not long before dinosaurs arose.”

U of Houston represents the consensus: that trilobites died out.

Wikipedia repeats that adage when they report, “Trilobites have no known direct descendants. Though horseshoe crabs are often cited as their closest living relatives, they are no closer evolutionarily than other chelicerates.”

There was a time not so long ago
when teachers used to tell their students dinosaurs are extinct. Then teachers had to correct themselves in the 1990s when monophyletic clades based on software-assisted phylogenetic analysies suddenly became ‘a thing’. And China began producing feathered dinosaurs and toothy birds by the hundreds. Sadly, all that ‘new insight’ arrived over a hundred years after Archaeopteryx was known to early adopters as a transitional dinosaur-to-bird.

Here online photos and graphics are collected
that you can show to your trilobite-loving friends… after first rousing yourself from your own paradigm slumber to digest and accept this tiny step away from tradition and consensus.

Figure 1. Early Cambrian Pseudosaukianda and Limulus. the extant horseshoe crab. In 540 million years these two have changed far less than our coeval chordate ancestors.

Trilobites evolved a variety of shapes and sizes.
Among them is the Early Cambrian genus, Pseudosaukianda (Fig 1), one with a telson. That trilobite genus generally matches the overall morphology of Limulus, the extant horseshoe crab (Figs 1, 3) and its transitional ancestors (Fig 2). Turns out that trillobite telson is retained in Limulus. It’s not there by convergence. There are no other taxa that have such a telson. None are closer to Limulus than Pseudosaukianda and its transitional kin (Fig 2).

But wait.
There’s more. Much more.

Figure 2. Horseshoe crab ancestors demonstrating the fusion of thorax elements. The earliest horseshoe crab traditionally post-dates Pseudosaukianda by 100 million years. It’s time for a paradigm shift.

In dorsal view
(Fig 3) both Pseudosaukianda and Limulus have similar morphologies with a similar number of lateral spines arising from the thorax, whether fused or not. In Limulus every other thorax segment evolves into a narrower lateral spine between wider lateral spines. Not much change here considering the half a billion years that separates these two.

Figure 3. In dorsal view Pseudosaukianda and Limulus share the same bauplan. In the horseshoe crab the thorax elements are now fused. That’s all and that’s not much for 540 million years of evolution.

In ventral view
both Pseudosaukianda and Limulus also have similar morphologies. Horseshoe crabs lose the gill element from the first six limbs and lose the limb element from the remaining gill plates. Both taxa have a ventral and central oral cavity between the bases of six sets of legs that all contribute to grabbing and processing food items before swallowing. This is not the way taxa derived from segmented annelids with a terminal mouth acquire food. It is the way primitive marine flatworms with a single central mouth/anus opening acquire food. Give a flatworm legs, armor and an anus and pretty soon you can call it a trilobite, as reported earlier here.

Figure 3. Trilobite limbs are rarely preserved, so Triarthrus limbs are modified here to fit the shorter morphology of Pseudosaukianda. The loss of limbs or gill plates is really the only difference between Pseudosaukianda and Limulus. Note how trilobites feed like flatworms. They cover their food items and use their proximal legs to draw it forward into the posteriorly-oriented ventral oral cavity. In horse shoe crabs this oral cavity is even more central to the leg bases.

Antennae
Horseshoe crabs lack antennae (Fig 3). Very few trilobites preserve antennae, legs + gills. So the reduction and loss of antennae between trilobites and horseshoe crabs has not been documented due to taphonomic (= preservation) issues.

In parasagittal view
(Fig 4) both the horseshoe crab and trilobite have a stomach filling or entering the anterior of their cephalon. The ventral mouth is posterior to this organ and is oriented posteriorly. A simple intestine extends to the posteroventral anus, opening beneath the base of the telson. The elongate heart/circulatory system is dorsal to the intestine. The brain + nervous system is ventral. It’s a pretty good match, both inside and outside. No other taxa are a closer match.

Figure 4. Triolbite and horseshoe crab in lateral view showing stomach (crop) in front of the brain, mouth opening posterior to the stomach, small brain ventral to these elements. All this is more like a marine flatworm than an arthropod. Crustaceans and insects are descendants of trilobites. Long narrow velvet worms and shorter tardigrades arise from nematodes (= round worms) and annelidids (segmented round worms).

If any other similar animal taxon has any part of its stomach in its head,
let me know. Likewise, if any other animals acquire and masticate food between the toothy ventral bases of their legs in the middle of their body, let me know. I am aware that crustacean, arachnid and insect mouth parts are former legs, but the feeding structures are all under a much smaller head in those taxa. When and if eventually tested here they will be compared.

It’s all about monophyly.
Horseshoe crabs are living trilobites, just like birds are theropod dinosaurs and humans are primates, placentals, mammals, amniotes, tetrapods, vertebrates and chordates. If you understand the concept of monophyletic clades, you’ll understand this apparently novel and long overdue hypothesis of interrelationships in trilobites. In evolution every living taxon is somehow connected to every other taxon. Separating for teaching purposes is appropriate. So is lumping.

This insight was low-hanging fruit
that should have been plucked decades ago. The practice of counting legs in arthropods (e.g. insects have six, spiders have eight) may be to blame here for the academic separation of Limulus from Pseudosaukianda, when they should have been lumped together as they are here. The opposite problem exists in diapsid-grade taxa that are not related to one another.

It is also important to not use suprageneric taxa.
Most trilobites are not appropriate outgroups for horseshoe crabs.

Please forgive this venture beyond chordates.
It was an issue that needed to be addressed.

The following horseshoe crab video sheds more light on this newly minted trilobite.
You’ll see the mouth central to the limbs in this inverted specimen. You’ll see the legs are now distinct from the gill plates. You’ll see this horseshoe crab curl up like a trilobite. You’ll see how harmless it is. You’ll see the primitive eyes and sex organs all presented by a knowledgeable handler. See video here. No preview was permitted. https://www.youtube.com/watch?v=rmlOAlodt54

One thing you won’t see
is how horseshoe crabs swim, which is rarely. They do the backstroke. Here’s a video on that:

References
trilobites.info/
trilobites.info/origins.htm
wiki/Telson
trilobites.info/moremorph.htm
wiki/Pseudosaukianda
wiki/Trilobite
wiki/Chelicerata

https://pterosaurheresies.wordpress.com/2021/06/01/cambroraster-documents-how-some-flatworms-became-trilobites/

Deinotherium enters the LRT with Gomphotherium

Known since Kaup 1829,
Deinotherium giganteum (Kaup 1829; Late Miocene; Figs 1, 2) is a large deinothere (Fig 2), the clade of elephants lacking premaxillary tusks. Instead large dentary (= mandible) tusks curl ventrally then posteriorly in all deinotheres (Fig 2) , distinct from all other elephant genera, as everyone already knows. Interrelationships have been traditionally murky since transitional taxa have not yet been documented.

Figure 1. Skull of Deinotherium in two views. Colors added here. Note the enormous naris visible in dorsal view. The nasals are either absent or fused to the frontals in this diagram.

Here
in the large reptile tree (LRT, 2061 taxa) Deinotherium (Fig 1) nests with Gomphotherium (Figs 3, 4), another tested taxon with large dentary tusks. Both arise from small pre-elephant taxa, like Notostylops (a pre-manatee) and Procavia, the extant hyrax.

Figure 2. Deinotherium figures from Larramendi 2016.

Larramendi 2016
published several excellent lateral view skeletons of deinotheres (Fig 2) and gomphotheres (Fig 3) along with several other elephant clades.

Larramendi 2016 calculated body mass in extinct taxa
“by the by the Graphic Double Integration volumetric method which is based on technical restorations from graphical reconstructions of fossils employing photos, measurements and comparative anatomy of extant forms. The method has been tested on extant elephants with highly accurate results. From the shoulder heights, several equations were created to find out the body mass of a series of extant and extinct species. A few of the largest proboscideans, namely Mammut borsoni and Palaeoloxodon namadicus, were found out to have reached and surpassed the body size of the largest indricotheres.”

In the LRT (Fig 5) indricotheres are giant three-toed horses.
Horses and rhinos are hyracodontids.
Those are tapir relatives.
Those are chalicothere and hyrax relatives.
Those are Ectocion relatives.
Those are artiodactyl relatives.
Those are oreodont and mesonychid relatives.
Etc.

Figure 3. Gomphotherium, like Deinotherium, had a longer dentary and dentary tusks.

A recent paper by Baleka et al. 2022
produced a phylogenetic analysis of elephants using total evidence (genes + traits). They wrote: “The order originated around 60 million years (Ma) ago in Africa. At present, the oldest proboscidean fossil is Phosphatherium escuilliei Gheerbrant, Sudre & Cappetta,1996, from Morocco. It comprises cranial and mandibular elements dating to 55 Ma (Gheerbrant,
2009).

We will take a closer look at Phosphatherium from Paleocene Morocco in the near future. Turns out it’s not a direct elephant ancestor (Fig 5) in the LRT.

Baleka et al. 2022 continue:
“The evolutionary history of proboscideans is marked by three major radiations.”

“The first occurred during the late Palaeocene/Eocene, with the diversification of primitive proboscideans.”

“The second radiation took place during the early Miocene, with the diversification of ‘‘Gomphotheriidae’’ Hay, 1922, (used sensu lato throughout the text, indicated by brackets) Mammutidae Hay, 1922, and Stegodontidae Osborn, 1918, a family within the Elephantoidea.”

“The last radiation took place during the late Miocene/early Pliocene and resulted in the diversification of Elephantidae Gray (1821), as well part of the superfamily Elephantoidea, including the living elephants.”

The LRT indicates elephant ancestors do not include Phosphatherium, but arise directly from Procavia-llike and Diadiaphorus-like tusked taxa.

Figure 4. Gomphotherium jaws. Note the elongate dentary and large dentary tusks. Those are not seen in other elephant clades.

Baleka et al. reported,
“The historical biogeography analysis (Figures 4, S4, and S5) suggests that proboscideans may have left Africa only three times in phylogenetically distant clades (Deinotherium or Deinotheriidae, Mammutidae, and Elephantida).”

The LRT nests Elephas with Mammuthus and Deinotherium with Gomphotherium.
Mammut (the mastodon) has not yet been tested.

Figure 5. Subset of the LRT focusing on elephants and their relatives. As in Baleka et al. 2022, Deinotheres are close to Palaeomastodon. Distinct from Bakeka et al. Gomphotherium nests with deinotheres here, rather than closer to extant elephants than Mammut the mammoth. Be wary of DNA studies.

References
Baleka et al. 2022. Revisiting proboscidean phylogeny and evolution through total evidence and palaeogenetic analyses including Notiomastodon ancient DNA. iScience 25, 103559 https://doi.org/10.1016/j.isci.2021.103559
Kaup JJ 1829. Neues Säugethier, Deinotherium: Deinotherium giganteum. Isis 22(4):401–404
Larramendi A 2016. Shoulder height, body mass, and shape of proboscideans. Acta Palaeontologica Polonica 61 (3):537–574.

Proboscidea Illiger 1811
alchetron.com/Deinotherium

Vanellus miles novaehollandiae: another spur-wing shore bird

Vanellus miles novaehollandiae
(Boddaert 1783; up to 37cm in length; Figs 1, 2) is the extant masked lapwing, aka spur-wing plover, of Australia and New Zealand, notable for transforming manus digit 1 into a formidable spike, and for those yellow facial wattles. Otherwise it is almost identical to the more plesiomorphic Charadrius. the plover, with which it nests in the LRT.

Figure 1. Vanellus the extant spur wing is not related to other spur-wings in the bird clade.

Figure 2. Skeleton of Vanellus with insets for the left and right manus. Digit 1 is colored red here.

Comparisons to the horned screamer,
Anhima (Fig 3), are warranted because both bear manus spurs. Analysis indicates the two do not nest together and the morphology of the spur arises from different bones.

Figure 3. Horned screamer (genus: Anhima) skeleton. Spiked manus is is purple. Note, the spike is separate and distinct from digit 1 here. Compare to figure 2.

Convergence
is demonstrated in this example of two unrelated birds with hand spurs.

References
Boddaert P 1763. The Histoire Naturelle, générale et particulière, avec la description du Cabinet du Roi (Natural History, General and Particular, with a Description of the King’s Cabinet)

The mouse lemur Microcebus: no longer a primate in the LRT

Traditionally the extant mouse lemur is the smallest primate.
This omnivore is native to Madagascar. Microcebus (Fig 1) is the single genus for several genetically split species. The smallest of these, M myoxinus (Fig 1) is much smaller than the pen-tailed tree shrew, Ptilocercus lowii (Fig 1). All species of Microcebus are likewise much smaller than Notharctus (Fig 1), the most primitive tested primate in the large reptile tree (LRT, 2061 taxa, subset Fig 2). Microcebus first entered the LRT in 2020 basal to Primates.

Figure 1. The gray mouse lemur (Microcebus murinus) nests basal to tree shrews in the LRT. Shown here about life size: 27 cm from snout tip to tail tip.

After taxon addition and score correction in the LRT
Microcebus now nests basal to the Ptilocercus + colugo + pandgolin + bat clade (= Volitantia), rather than anywhere in or before the Primates clade. Despite nesting one node apart from Primates, (Fig 2), forcing Microcebus back to Primates adds seven steps with current scoring and taxa.

Figure 2. Subset of the LRT focusing on primates and the Jurassic descendants of a Jurassic sister to the basalmost tested primate, Notharctus. Now you know why squirrels are so at home in the trees. They are descendants of Jurassic lemur-like primates.

According to Janecka et al. 2007
“In order to resolve the ancestral relationships among primates and their closest relatives, we searched multispecies genome alignments for phylogenetically informative rare genomic changes within the superordinal group Euarchonta, which includes the orders Primates, Dermoptera (colugos), and Scandentia (treeshrews).”

The LRT adds shrews and Glires (gnawing taxa) to this list with Notharctus, a primitive adapid (= extinct lemurs living outside of Madagascar) at the base of all Euarchonta.

“We also constructed phylogenetic trees from 14 kilobases of nuclear genes for representatives from most major primate lineages, both extant colugos, and multiple treeshrews, including the pentail treeshrew, Ptilocercus lowii, the only living member of the family Ptilocercidae.”

Excessive splitting here.
The LRT relates every tested taxon to every other. None stand alone.

“A relaxed molecular clock analysis including Ptilocercus suggests that treeshrews arose approximately 63 million years ago. Our data show that colugos are the closest living relatives of primates and indicate that their divergence occurred in the Cretaceous.”

According to the LRT, Notharctus, Microcebus and Ptilocercus (Fig 1) must be
much older: Early to Middle Jurassic in origin because derived members of their clade, the Multituberculates, appear in the Middle to Late Jurassic.

According to the LRT Euarchonta should be redefined to include Glires and Multituberculata.

Did someone mention phylogenetic miniaturization?
If not, I’ll bring it up. Since Microcebus is a tiny Notharctus and it nests at the genesis of a new clade it qualifies as a phylogenetically miniaturized taxon, something we’ve seen over and over. Note the neotony in Microcebus: shorter rostrum, larger orbits, smaller overall as an adult, compared to Notharctus (Fig 1). Take a moment to do this: scroll up and down to compare the two and you’ll get an appreciation for the way evolution really works, sometimes with phylogenetic miniaturization = precocious sexual maturity.

The mouse lemur is not the first former primate to leave the clade.
Long time readers might remember the aye-aye, Daubentonia left the primates back in 2016. Likewise, the classic plesiadapiform, Plesiadapis, is a Daubentonia relative and closer to Carpolestes and multituberculates (Fig 2) than to any primate.

This latest bit of heresy was brought to you by taxon inclusion.
Whenever taxa are tested together that have never been tested together, sometimes they switch clades. Sometimes the unexpected happens. We’ve seen this time and again.

References
Janečka, JE et al. (seven co-authors) 2007. Molecular and Genomic Data Identify the Closest Living Relative of Primates. Science. 318 (5851): 792–794. Bibcode:2007Sci…318..792J. doi:10.1126/science.1147555.

The basalmost primate in the LRT is alive and living in Madagascar!

The aye-aye (Daubentonia) is not a primate.

Oenosaurus: another tiny rhynchocephalian, this time closer to rhychosaurs

Oenosaurus muehlheimensis (Rauhut et al. 2012; Late Jurassic; BSPG 2009 I 23; Fig 1) was originally considered a rhynchocephalian (Fig 2) close to the extant tuatara (Sphenodon), but with an unique fusion of all the teeth to make crushing plates.

We just recently looked at another tiny rhynchocephalian,
Navajosphenodon, after a very long dry spell. So it’s good to crack our knuckles on this misunderstood clade (see below) once again. Benton 1985 once again comes under scrutiny.

Figure 1. Diagram from Rauhut et al. 2012 of Oenosaurus. Colors and reconstruction added here. Colors without outlines are restored missing pieces based on related taxa and skull shape. For instance the rostrum is restored no longer than the mandible.

Rauhut et al. report,
“The dentition of Oenosaurus is unique amongst tetrapods. Although tooth batteries are known in a small number of groups, including captorhinomorphs, rhynchosaurs, and advanced ornithischian dinosaurs, and plate-like teeth are present in placodonts, the detailed structure of these dentitions was markedly different. The tooth plates of Oenosaurus consist of a multitude
of minute, closely packed and co-cemented dentine tubes without any discernible pattern of tooth rows or tooth generations.”

Since Rauhut et al were aware of rhynchosaurs (see above) it is surprising to see them excluded from the Rauhut et al. cladogram (Fig 3). By contrast the LRT (Fig 4) tests a wide gamut of taxa from sharks to birds. Therein rhynchosaurs and trilophosaurs nest with sphenodontians in the clade Rhynchocephalia, resurrecting an old hypothesis of interrelationships.

Figure 3. Oenosaurus cladogram from Rauhut 2012 lacks many taxa tested in the LRT.

Here
in the large reptile tree (LRT, 2061 taxa; Fig 3) Oenosaurus nests at the base of the Mesosuchus (Fig 5) + Rhynchosaurus clade, derived from trilophosaurs (Fig 5) and all nesting within the clade Rhynchocephalia. The tiny size of Oenosaurus (Fig 4) is just one more example of phylogenetic miniaturization at the genesis of a new clade. This taxon is a late survivor of an Early Triassic radiation. Teeth go through many changes in this clade.

Figure 4. Subset of the LRT focusing on Rhynchocephalia. Oenosaurus nests here basal to the Mesosuchus – Rhynchosaurus clade. Butler et al. 2015 labeled Eohysaurus a basal rhynchosaur. Rauhut et al. 2012 labeled Oenosaurus a rhynchocephalian. Here no taxa separate them.

In the earliest days of software assisted phylogenetic analysis
Benton 1985 separated Rhynchochephalia from Rhynchosauria following Carroll 1977 (see below). Benton wrote: “There is no close relationship betwcen rhynchosaurs and sphenodontids, nor between Prolacerta or ‘Tanystropheus and lizards. The lepidosaurs are in fact the sister-group of the crocodiles. It will be argued here that the most parsimonious arrangement of living reptiles is to accept the monophyly of the diapsids-that the archosaurs (including birds) are the sistergroup of the lepidosaurs.”

Benton was much younger back then. He was eager to tackle the largest problems in vertebrate paleontology, but unwilling to put a decade and thousands of taxa into the research. Benton’s gamble and efforts paid off. He became a professor, wrote several textbooks and influenced the next several generations of paleontologists.

Unfortunately Benton cherry-picked taxa.
As a result Benton omitted many taxa that would have changed his tree topology where Reptilia split immediately into Archosauromorpha (including mammals) and Lepidosauromorpha (including turtles) using traditional definitions. Diapsid-grade taxa arose twice, once in each clade. Still in his naive twenties, Benton had no idea of any of this due to taxon exclusion. Back in 1985 workers thought once you had a diapsid skull morphology, you had it forever and no other taxa would ever develop it by convergence. The LRT invalidated those assumptions.

To his credit,
Benton 1985 innocently nested Pterosauria between the taxa Lepidosauromorpha, Trilophosaurus, and Rhynchosauria. All are lepidosauriformes in the LRT. Benton doesn’t do that nowadays.

To his discredit,
Benton 1985 nested Prolacerta with Macrocnemus, apart from Protorosaurus.

To his discredit
Benton1985 nested Tanystropheus + Tanytrachelos apart from Pterosauria, perhaps due to not scoring the identical pedal elements and employing several suprageneric taxa.

Benton 1985 was aware of the pterosaur precursor,
Cosesaurus. He wrote, “Cosesaurus from the Muschelkalk of Spain, claimed to be a bird ancestor (Ellenberger & Villalta, 1974) may be a prolacertiform (Olsen, 1979), although in the original description “la fosse anté-orbitale” is said to be long.” So he didn’t examine the specimen. That’s unfortunate because that would have changed his life and mine.

Benton reports,
“The relationships of Proterosuchus are uncertain.” He marked a dashed line from Prolacerta to Proterosuchus and another dashed line from Erythrosuchus to Proterosuchus. Both dashed lines are correct, but the topology is off. In the LRT Prolacerta gave rise to the Proterosuchus clade via the AMNH 5561 specimen of Youngina. Meanwhile Prolacerta also gave rise to the Erythrosuchus clade via the UC1528 specimen of Youngoides + Euparkeria. That’s how the Archosauriformes split at their origin. Adding taxa solves all phylogenetic problems. Why don’t more paleontologists do this? Quoting Darren Naish on FB, “It’s too much work.”

Since then
no one tested Benton’s many mistaken hypothesis of interrelationships at the genus level with a much wider gamut of taxa until the LRT did so a decade ago. With the same youthful ambition Nesbitt 2011 attempted Benton’s task, but likewise suffered from taxon exclusion and a raft of bad scores.

Figure 5. Various Rhynchocephalians in the clade Rhychocephalia. Note the small size of late-surviving Oenosaurus, slightly larger than the phylogenetically earlier Navajosphenodon.

Carroll 1977 reported,
“It was long thought that rhynchosaurs were closely related to modern sphendontids on the basis of general similarities of the skull and dentition. The common presence of primitive features such as the lower temporal bar only points to their common origin among early diapsids. Although the dentition appears to be vaguely similar, it is fundamentally different.“

What was Carroll doing in 1977? He was “Pulling a Larry Martin”. In other words, he was overlooking all the general similarities in favor of fundamentally different teeth.

Lesson from the mistake made by Carroll 1977:
Never, ever label a taxon based on its dentition or any other short list of characters. Always use hundreds of traits from snout to tail tip, if possible, and run those traits through phylogenetic analysis using a wide gamut of possible candidate taxa. Let the software tell you the most parsimonious solution. Don’t pre-guess based on a focused observation, no matter how professional you deem your observation. Especially don’t base a hunch on dental traits. Those tend to converge with unrelated taxa and to change with related taxa (Fig 5), not as a rule, but often enough to avoid relying on them alone, especially in the transition from basal rhynchocephalians to derived rhynchosaurs. At present only in the LRT can one document the gradual accumulation of derived traits, and a few reversals, that went in to the evolution of trilophosaurs and rhynchosaurs from basal sphenodontids.

The monophyly of the Rhynchocephalia
is a resurrected hypothesis of interrelationships. Let me know if others have done so and where a similar taxon list (Fig 4) has been published in the last thirty years.

References
Benton M J 1983. TheTriassic reptile Hyperodapedon from Elgin: functional morphology and relationships. Phil. Trans. R. Soc. Lond. B 302, 605^717. Carroll, R. L. 1988 Vertebrate paleontology and evolution. New York: W. H. Freeman & Co.
Benton MJ 1985. Classification and phylogeny of diapsid reptiles. Zoological Journal of the Linnean Society 84: 97-164.
Butler R, Ezcurra M, Montefeltro F, Samathi A, Sobral G 2015. A new species of basal rhynchosaur (Diapsida: Archosauromorpha) from the early Middle Triassic of South Africa, and the early evolution of Rhynchosauria. Zoological Journal of the Linnean Society 10.1111/zoj.12246.
Carroll RL 1977. The origin of lizards. In Andrews, Miles and Walker [eds.] Problems of Vertebrate Evolution. Linnean Society Symposium Series 4: 359–396.
Carroll RL 1988. Vertebrate Paleontology and Evolution. W. H. Freeman and Co. New York.
Nesbitt SJ 2011. The early evolution of archosaurs: relationships and the origin of major clades. Bulletin of the American Museum of Natural History 352: 292 pp.
Rauhut OWM, Heyng AM, López-Arbarello A, Hecker A 2012. A New Rhynchocephalian from the Late Jurassic of Germany with a Dentition That Is Unique amongst Tetrapods. PLoS ONE 7(10): e46839. doi:10.1371/journal.pone.0046839
Watson, DMS 1912. Mesosuchus browni, gen. et spec. nov. Rec. Albany Museum 2, 296-297.

wiki/Mesosuchus
wiki/Eohyosaurus
wiki/Oenosaurus

Moving Rhynchosaurs and Trilophosaurs Back into the Rhynchocephalia (Sphenodontia)

Tiny toothy Navajosphenodon enters the LRT basal to Trilophosaurus, not with beaked Sphenodon

Arguments against the Rhynchosaur/Rhynchocephalian Rhylationship

Late Cretaceous Papiliovenator enters the LRT with Early Cretaceous Daliansaurus, a previously overlooked taxon

From the Pei et al. abstract:
“A new troodontid dinosaur, Papiliovenator neimengguensis gen. et sp. nov., from the Upper Cretaceous (Campanian) Wulansuhai Formation at Bayan Manduhu, Inner Mongolia, China, is described here. The holotype (BNMNH-PV030) consists of a nearly complete cranium and fragmentary postcranial bones in semi-articulation and this specimen is inferred as a subadult based on the osteohistological information and the fusion of bones.

Perhaps it is time to separate the dromaeosaurid-like troodontids from the pre-bird troodontids (= anchiornithids). Many of the latter, especially the large ones, have been traditionally considered troodontids. Papiliovenator is one of these. So is Daliansaurus (Fig 1).

Figure 1. Anchiornithids close to Daliansaurus including Papiliovenator.

From the Pei et al. abstract:
Papiliovenator neimengguensis is distinguishable from other troodontids based on a suite of features such as the lateral groove of the dentary not posteriorly expanded, a deep surangular fossa anteroventral to the glenoid fossa and hosting the surangular foramen, the ventral ridge of the surangular fossa mainly on the surangular, and a unique anterolaterally broadened and butterfly-shaped neural arch of the anteriormost dorsal vertebrae in dorsal view.

The large reptile tree (LRT, 2060 taxa) nests Late Cretaceous Papiliovenator with Early Cretaceous Daliansaurus, a taxon known from more complete post-crania, but less complete crania. What little that is known is a good match, both in morphology and size (Fig 1).

Our phylogenetic analysis recovered Papiliovenator neimengguensis at the earliest-diverging branch of a clade including all other Late Cretaceous troodontids except Almas. The discovery of Papiliovenator neimengguensis allows for an improved understanding of troodontid anatomy, as well as the regional variation of troodontids from the Upper Cretaceous of the Gobi Basin.”

Figure 2. Papiliovenator skull in two views. Colors added here. The LRT nests this taxon with Daliansaurus, which preserves more post-crania.

According to Wikipedia,
“The holotype, BNMNH-PV030, is a partial, semi-articulated subadult skeleton consisting of a nearly complete cranium and other postcranial bones. Uniquely, its snout was short and subtriangular, more similar to that of Early Cretaceous troodontids such as Mei long than the long, low snouts of Late Cretaceous troodontids. This and other unique traits of its skeleton suggest a high diversity of troodontid morphotypes in the Late Cretaceous Gobi Desert.”

In the LRT
Mei long nests within the clade of basal birds (Scansoriopterygidae) in the LRT (subset Fig 2), not with more primitive troodontids. Obviously Mei long was flightless, given its short forelimbs and hands. That doesn’t matter. Overall, when all traits are tested, Mei long nests as an early flightless bird with short limbs. That’s a reversal. and that’s okay. The LRT sheds light on many such reversals.

Many of the most primitive extant birds
are also flightless with short forelimbs, and some tend to become the largest birds of the present era. This is a pattern we must be ready to accept, especially when cladograms recover such interrelationships.

Figure 2. Theropod cladogram from a short while back. Zanabazar nests close to Haplocheirus (light green clade). Almas nests several nodes apart in the pre-bird clade (beige grade).

The Pei et al. cladogram
nests Late Cretaceous Papiliovenator between Almas (Fig 1) an anchiornithid and Zanabazar a taxon close to Haplocheirus. The LRT does not nest Almas and Zanabazar close to one another, but does nest Papiliovenator between them, separated from both by several taxa. Early Cretaceous Daliansaurus was not mentioned despite apparent similarities in morphology and size.

Daliansaurus liaoningensis (Shen et al. 2017; Early Cretaceous, Barremian, 128 mya; 1 m long) nests in the LRT as a basal anchiornithid, not a troodontid.

Papiliovenator neimengguensis.(Pei et al. 2022; Late Cretaceous, Cenomian) nests with previously overlooked Daliansaurus in the LRT.

References
Pei et al. (12 co-authors) 2021. A new troodontid from the Upper Cretaceous Gobi Basin of inner Mongolia, China. Cretaceous Research 130:

Poebrotherium enters the LRT at the base of camels

Slender, two-toed Poebrotherium
(Figs 1, 2) is traditionally considered basal to camels. In the large reptile tree (LRT, 2060 taxa, subset Fig 6) Poebrotherium likewise nests basal to camels, which are basal to cattle, giraffids, sheep and deer in the LRT.

Figure 1. Poebrotherium skull. Colors added here. Note the lack of a diastema (= area lacking teeth), a trait typical of derived taxa. Note the umlauts are suppressed here, a rule just now brought to my attention.

Figure 2. Skeleton of Poebrotherium.

Here’s where the heresies kick in
Litolophus (Fig 3), a traditional crested chalicothere with small round hooves, now nests basal to camels in the LRT. The resemblance to Poebrotherium (Fig 2) is notable and more so than to any chalicothere or any other LRT taxon according to the scores.

Figure 3. Litolophus is a traditional chalicothere that nests basal to camels and kin in the LRT.

Basal to Litolophus
is Ectocion cedrus (Fig 4), a traditional phenacodontid. This smaller, more plesiomorphic taxon nests apart from Ectocion ralstonensis, which nests closer to hyraxes in the LRT. So these two are not congeneric.

Ectocion cedrus now links tall slender artiodactyls,
like Litolophus (Fig 3), camels, deer and cattle, to the clade of pigs, the other traditional artiodactyl clade, now somewhat separated from the camels by these two taxa (see Fig 6) that other workers did not consider to be basal artiodactyls.

Figure 4. Ectocion cedrus is the basalmost artiodactyl in the camel clade. Note its resemblance to the basalmost taxon in the pig clade, Cainotherium in figure 5.

Pig ancestors
include four-toed Cainotherium (Fig 5) a late surviving Late Eocene slender grazer, which greatly resembles Ectocion cedrus (Fig 4) from the Paleocene. These taxa are all part of the radiation of terrestrial herbivores following the K-Pg extinction event.

Figure 5. Cainotherium nests basal to the pig clade in the LRT.

Several placental taxa recently added to the LRT
(subset Fig 6) have clarified hypothetical interrelationships in the resurrected clade Condylarthra. Adding taxa always seems to shed new light here in the LRT and elsewhere.

Figure 6. Subset of the LRT focusing on condylathran placentals, all arising after the K-Pg extinction event and all showing trends toward terrestrial locomotion and herbivory. Some like goats and tree sloths have, one way or another, returned to the tree.

The LRT remains fully resolved
employing 2060 taxa tested using 236 multistate characters.

References
Prothero et al. (15 co-authors) 2021. On the Unnecessary and Misleading Taxon “Cetartiodactyla”. Journal of Mammalian Evolution. https://doi.org/10.1007/s10914-021-09572-7

Newest pterosaur ‘ancestor’ paper admits “postcranial skeleton of lagerpetids and pterosaurs are very different” while omitting actual pterosaur ancestors

Müller 2022 reports lagerpetids are pterosaur ancestors.
“Exquisite [translation = partial, bits and pieces from around the world] discoveries and new interpretations regarding an enigmatic group of cursorial avemetatarsalians led to a new phylogenetic hypothesis regarding pterosaur affinities. Previously thought to be dinosaur precursors, lagerpetids are now considered to be the closest relatives to pterosaurs

Taxon exclusion is present here: Actual pterosaur ancestors, like Cosesaurus (Fig 1), are known from four complete specimens, three with soft tissues.

Avemetatarsalia is junior synonym for Reptilia in the LRT.

Figure 1. CLICK TO ENLARGE. Cosesaurus reconstructed with enlarged parts of interest including a pes (foot) matching a Rotodactylus track. Here the pelvis is reconstructed according to figure 3. Shown here about life-size.

Contra Müeller 2022,
Lagerpeton (Fig 2) and kin are known from bits and pieces, all with better matches to Tropidosuchus (Fig 2) a proterochampsid. They have to be cobbled together to create one specimen and even then large missing areas are filled in by imaginative artists (Fig 3). By constrast, fenestrasaur ancestors to pterosaurs (e.g. Fig 1) are all complete and articulated.

Figure 2. Tropidosuchus and Lagerpeton compared to the new material (MCZ 101542).

From the Müeller 2022 abstract:
“This new hypothesis sheds light on a new explorable field, especially regarding the character acquisition and evolution within the pterosaur lineage. In the present study, the morphospace occupation of distinct skeletal regions of lagerpetids withing the morphological spectrum of avemetatarsalians is investigated. This approach indicates which portions of the skeleton are more similar to the anatomy of pterosaurs and which portions present different homoplastic signals.“

Lagepetids are bipedal proterochampsids close to Tropidosuchus.
Neither are close to pterosaurs in the LRT where all competing taxa are tested. Wishful thinking with blinders on, is not science.

“The analyses demonstrates that the craniomandibular traits of lagerpetids are pterosaur-like, the pectoral girdle and forelimb are dinosauromorph-like and the axial skeleton and the pelvic girdle and hindlimb are unique and highly specialized among the analysed sample.“

In Fenestrasaurs like Cosesaurus (Fig 1), the skull is pterosaur-like, the post-crania is pterosaur-like and the soft tissue is pterosaur-like. In transitional taxa, like Sharovipteryx and Longisquama, pterosaur traits, like a longer, more robust finger 4, are present. Omitting these taxa is like shooting yourself in the foot if you want to learn about pterosaurs.

“So, despite the close phylogenetic relationships, the postcranial skeleton of lagerpetids and pterosaurs are very different.”

They don’t look alike because they are not related to pterosaurs.

“The occurrence of two distinct and highly specialized groups of pterosauromorphs coexisting with a wide ecological range of dinosauromorphs during Triassic suggests pressure for new niches occupation.”

In evolution changes are gradual with incremental changes in all aspects of the morphology documented only in fenestrasaurs like Cosesaurus (Fig 1).

Figure 3. Image from Muller 2022 of a chimaera of several purported lagerpetids from around the world. Compare this cobbled-together skeleton built from scraps of several genera compares to the complete and articulated skeleton with soft tissues of Cosesaurus in figure 1 that was ignored by Muller 2022. Taxa closer to pterosaurs, like Sharovipteryx and Longisquama increase the length and robust morphology of finger four. The wings came last in pterosaurs (Peters 2002).

Only a wide gamut phylogenetic analysis
that includes all competing taxa can determine the closest relatives of pterosaurs. Lagerpetids are not related to pterosaurs when more taxa are added to analysis.

Here is the competing cladogram.
I have studied and published on the closest relatives of pterosaurs, all of which have cranial, post-cranial traits otherwise only found in pterosaurs.

Here is data on Cosesaurus
Müller chose not to study.

Ignoring and omitting the actual ancestors of pterosaurs
has been a running gag for the last twenty years in the academic community, and it casts a pall on every member of the community that participates.

There’s a bit of back and forth (= bickering) going on
over at ResearchGate, where the Muller paper is available as a free PDF.

In the ‘comments’ section I wrote: “The abstract states, “the postcranial skeleton of lagerpetids and pterosaurs are very different.” That means they are NOT closely related. We have a phylogenetic series of pterosaur ancestors with very similar crania and post-crania… and soft tissues, arising from an overlooked clade of lepidosaurs. More information here: Preprint Cosesaurus aviceps, Sharovipteryx mirabilis and Longisquama …

Cristian Pereyra Universidad Nacional de La Plata wrote: “Social network or blogs lack scientific relevance or support. The medium for scientific interchange are scientific journals, different approaches should be published accordingly and accepted in the community. The work of Muller employs large data sets in which cosesaurus and kin are not considered close relatives, so, publish a rebutal for that based on large datasets in a scientific journal, not a blog.”

My reply: “To your point, Christian, when you say Muller employs large data sets in which cosesaurus an kin are not considered close relatives, what you mean and what Muller did, was to omit them from the large data set. They were not considered. To your point, Muller didn’t publish a rebuttal to Peters 2000. He chose to ignore it. That’s keeping one’s blinders on. If Muller had a good case for his preferred taxon, rebutting Peters 2000 should have been easy. Please note that the illustration of the lagerpetid in Muller 2022 has a finger four smaller than the others. This is common in archosauriformes. Not what one looks for in a pterosaur ancestor. Adding taxa nests Lagerpeton with the proterochampsid, Tropidosuchus and Ixalerpeton nests within protorosauria.”

The author Rodrigo Müller is a young paleontologist
who has embraced a recent misguided wave of enthusiasm for lagerpetids as pterosaur ancestors. In such efforts workers are seeking to discover something that was long ago discovered, verified in several analyses and published in Peters 2000. By Müller citing this publication, then omitting the pterosaur precursors therein is inappropriate. And yet it happens over and and over again, supported by editors and referees.

Don’t cherry pick your pterosaur ancestors.
Let your wide gamut phylogenetic analysis tell you which taxa were ancestral to pterosaurs. Add enough taxa from a wide enough gamut and you, too, will recover the four best taxa ancestral to pterosaurs. Of course this goes the same for any other taxa that piques your intererest (e.g. whales, turtles, snakes, reptiles, etc.) The LRT does it all.

When I first set eyes on Cosesaurus
in Barcelona, it was ignominiously wrapped in a few layers of toilet paper. I didn’t realize it then, more than two decades ago, but that humble wrapping has now become symbolic of how the paleo world thinks of this important key taxon. Several phylogenetic analyses have shown that Cosesaurus is the ‘Archaeopteryx‘ of pterosaurs. Unfortunately, no one wants to let it have that honor, and they do so by ignoring it. The last twenty-two years of being a supporter for Cosesaurus has been a bit more dramatic and long lasting than I ever thought.

References
Müller RT 2022. The closest evolutionary relatives of pterosaurs: what the morphospace occupation of different skeletal regions tell us about lagerpetids. The Anatomical Record. https://doi.org/10.1002/ar.24904
Peters D 2000. A Redescription of Four Prolacertiform Genera and Implications for Pterosaur Phylogenesis. Rivista Italiana di Paleontologia e Stratigrafia 106 (3): 293–336.
Peters D 2002. A New Model for the Evolution of the Pterosaur Wing – with a twist. – Historical Biology 15: 277–301.
Peters D unpublished. Cosesaurus aviceps, Sharovipteryx mirabilis and Longisquama insignis reinterpreted. PDF

Kongonaphon kely: a tiny ornithodiran? NO!

Timeline of pterosaur origin studies