https://www.science.org/doi/10.1126/science.abq2835
The evolution of hominoid locomotor versatility:
Evidence from Moroto, a 21 Ma site in Uganda
MacLatchy et al., Science 380, 172 (2023 14 April 2023

INTRODUCTION:
Inherent in traditional views of ape origins is the
idea that, like living apes, early large-bodied apes
lived in tropical forests. In response to constraints
related to locomoting in forest canopies, it has been
proposed that early apes evolved their quintessential
upright torsos and acrobatic climbing and suspensory
abilities, enhancing their locomotor versatility, to
distribute their weight among small supports and thus
reach ripe fruit in the terminal branches. This
feeding and locomotor transition from a quadruped
with a horizontal torso is thought to have occurred
in the Middle Miocene due to an increasingly seasonal
climate and feeding competition from evolving monkeys.
....

RESULTS: A short, strong femur biomechanically
favorable to vertical climbing and a vertebra
indicating a dorsostable lower back
confirmthat ape fossils fromMoroto II shared
locomotor traits with living apes. Both
Morotopithecus and a smaller ape from the
site have elongated molars with well-developed
crests for shearing leaves. Carbon isotopic
signatures of the enamel of these apes and of
other fossil mammals indicate that some mammals
consistently fed onwater-stressedC3 plants,
and possibly also C4 vegetation, in a woodland
setting. Carbon isotope values of pedogenic
carbonates, paleosol organic matter, and plant
waxes all point to substantial C4 grass biomass
on the landscape. Analysis of paleosols also
indicates subhumid, strongly seasonal rainfall,
and phytolith assemblages include forms from
both aridadapted C4 grasses and forest-indicator
plants.

CONCLUSION: The ancient co-occurrence of
dental specializations for leaf eating, rather
than ripe fruit consumption, along with apelike
locomotor abilities counters the predictions
of the terminal branch forest frugivory
hypotheses. The combined paleoecological
evidence situates Morotopithecus in a woodland
with a broken canopy and substantial
grass understory including C4 species. These
findings call for a new paradigm for the
evolutionary origins of early apes. We propose
that seasonal, wooded environments may have
exerted previously unrecognized selective
pressures in the evolution of arboreal apes.
For example, some apes may have needed to
access leaves in the higher canopy in times of
low fruit availability and to be adept at
ascending and descending from trees that lacked
a continuous canopy.

Abstract
Living hominoids are distinguished by upright
torsos and versatile locomotion. It is
hypothesized that these features evolved for
feeding on fruit from terminal branches in
forests. To investigate the evolutionary context
of hominoid adaptive origins, we analyzed
multiple paleoenvironmental proxies in
conjunction with hominoid fossils from the
Moroto II site in Uganda. The data indicate
seasonally dry woodlands with the earliest
evidence of abundant C4 grasses in Africa based
on a confirmed age of 21 million years ago (Ma).
We demonstrate that the leaf-eating hominoid
Morotopithecus consumed water-stressed
vegetation, and postcrania from the site
indicate ape-like locomotor adaptations. These
findings suggest that the origin of hominoid
locomotor versatility is associated with
foraging on leaves in heterogeneous, open
woodlands rather than forests.

"Compositionally, this assemblage has affinities
with modern phytolith assemblages fromwooded
grasslands, but it is also consistent with open
forests containing a substantial grass understory
(e.g., riparian forest in a savanna landscape,
dry forest, or forest openings)."

Xth fantasy:

> https://www.science.org/doi/10.1126/science.abq2835
> The evolution of hominoid locomotor versatility:
> Evidence from Moroto, a 21 Ma site in Uganda
> MacLatchy et al., Science 380, 172 (2023 14 April 2023
> Inherent in traditional views of ape origins is the
> idea that, like living apes, early large-bodied apes
> lived in tropical forests. In response to constraints
> related to locomoting in forest canopies, it has been
> proposed that early apes evolved their quintessential
> upright torsos and acrobatic climbing and suspensory
> abilities, enhancing their locomotor versatility, to
> distribute their weight among small supports and thus
> reach ripe fruit in the terminal branches. This
> feeding and locomotor transition from a quadruped
> with a horizontal torso is thought to have occurred
> in the Middle Miocene due to an increasingly seasonal
> climate and feeding competition from evolving monkeys.

IOW, just-so musings on some Miocene African catarrhine fossil.
Great & lesser apes already split *early*Miocene,
probably somewhere in S-Asia
(I'd think in India: my book p.299, google "gondwanatalks vehaegen"
https://www.gondwanatalks.com/l/the-waterside-hypothesis-wading-led-to-upright-walking-in-early-humans/).

> RESULTS: A short, strong femur biomechanically
> favorable to vertical climbing and a vertebra
> indicating a dorsostable lower back

??
based on??

> confirm that ape fossils from Moroto II shared
> locomotor traits with living apes.

A lot of Miocene primates might evolved some convergence with hominoids.

> Both
> Morotopithecus and a smaller ape from the
> site have elongated molars with well-developed
> crests for shearing leaves. Carbon isotopic
> signatures of the enamel of these apes and of
> other fossil mammals indicate that some mammals
> consistently fed on water-stressed C3 plants,
> and possibly also C4 vegetation, in a woodland
> setting. Carbon isotope values of pedogenic
> carbonates, paleosol organic matter, and plant
> waxes all point to substantial C4 grass biomass
> on the landscape. Analysis of paleosols also
> indicates subhumid, strongly seasonal rainfall,
> and phytolith assemblages include forms from
> both arid adapted C4 grasses and forest-indicator
> plants.
> CONCLUSION: The ancient co-occurrence of
> dental specializations for leaf eating, rather
> than ripe fruit consumption, along with apelike

??
:-DDD
Apes have
-- no tail,
-- 4 or 5 lumbar vertebras,
-- broad sternum (Latisternalia),
-- ...

> locomotor abilities counters the predictions
> of the terminal branch forest frugivory
> hypotheses. The combined paleoecological
> evidence situates Morotopithecus in a woodland
> with a broken canopy and substantial
> grass understory including C4 species. These
> findings call for a new paradigm for the
> evolutionary origins of early apes. We propose
> that seasonal, wooded environments may have
> exerted previously unrecognized selective
> pressures in the evolution of arboreal apes.
> For example, some apes may have needed to
> access leaves in the higher canopy in times of
> low fruit availability and to be adept at
> ascending and descending from trees that lacked
> a continuous canopy.
> Abstract
> Living hominoids are distinguished by upright
> torsos and versatile locomotion. It is
> hypothesized that these features evolved for
> feeding on fruit from terminal branches in
> forests. To investigate the evolutionary context
> of hominoid adaptive origins, we analyzed
> multiple paleoenvironmental proxies in
> conjunction with hominoid fossils from the
> Moroto II site in Uganda. The data indicate
> seasonally dry woodlands with the earliest
> evidence of abundant C4 grasses in Africa based
> on a confirmed age of 21 million years ago (Ma).
> We demonstrate that the leaf-eating hominoid
> Morotopithecus consumed water-stressed
> vegetation, and postcrania from the site
> indicate ape-like locomotor adaptations. These
> findings suggest that the origin of hominoid
> locomotor versatility is associated with
> foraging on leaves in heterogeneous, open
> woodlands rather than forests.
> "Compositionally, this assemblage has affinities
> with modern phytolith assemblages fromwooded
> grasslands, but it is also consistent with open
> forests containing a substantial grass understory
> (e.g. riparian forest in a savanna landscape,
> dry forest, or forest openings)."

IOW, Morotopithecus was probably not hominoid:
probably above-brancher with 6 or 7 lumbar vertebras.

Most likely, Hominoidea originated in S-Asia:
most hominoids in SE.Asia: siamangs & gibbons,
pongids also in SE.Asia,
Homo worldwide (H.erectus Java),
only Pan & Gorilla in Africa.

Discussion of Morotopith cs in my book p.72-74:
Ugandapithecus (22–15 Ma), ontdekt bij fossiele krokodillen, waterschildpadden en waterdwerghertjes (Dorcatherium), wordt nu onderscheiden van Proconsul (Pickford 2009, Senut 2016): ze waren vaak veel groter (U.major-mannen tot 90 kg), allicht al rechtop klimmend, met een lang vlak gelaat, baviaan-grote hersenen, brede middenste bovensnijtanden, steviger hoektanden, en op de kiezen rondere knobbels met soms gerimpeld glazuur (planteneten?) en kenmerken die wat deden denken aan latere mensapen in Ethiopië en Kenya (Chorora-, Nakali- en Samburupithecus ~10 Ma) – en in sommige reconstructies, voor zover ik kan zien, ook aan Moroto~Afro~Heliopithecus:
Morotopithecus (~21 Ma? ~40 kg) had een groot gebit en schedel gelijkend op Afro- en Heliopithecus hieronder: brede neus, grote kaakholtes, lang gelaat met een lange rij kiezen met dik kiesglazuur (met kammen voor bladeten, denkt Laura MacLatchy), vooruitstekende snijtanden en massieve hoektanden (maar zonder Afropithecus' saki-achtige specialisatie, zegt Andrew Deane). De dijbotkop was ‘primitief’ zoals bij hondapen (boventakkers), maar de dijschacht was kort en uitzonderlijk zwaar (nog zwaarder dan bij lori’s en orangs, trage hangklimmers – erg zware pootbotten zie je bij zeeotters, nijlpaarden en Pakicetus, een vermoedelijk-wadende oerwalvis). Er waren blijkbaar 7 of 6 lendenwervels zoals bij de meeste apen en Proconsul (mensen en gibbons ~5, grote-mensapen ~4), maar de erg ‘lage’ lendenwervels, de lange doornuitsteeksels achteraan de wervels, en de zoals bij ons naar achteren opgeschoven stevige dwarsuitsteeksels (processus transversi, Sanders 1993) doen denken aan een stijf opgerichte romp, voor tweebenigheid volgens Aaron Filler – ik denk verticaal klimmen en waden en misschien drijven in waterbos. De begeleidende fauna wees op een soort dambo, zegt Brigitte Senut: drasland vol biezen en zeggen, dat in het natte seizoen sterk onderwater staat. Martin Pickford twijfelt of de zware dijbotten en ‘moderne’ wervels wel bij de schedel horen, en volgens Masato Nakatsukasa leek het dwarsuitsteeksel onafhankelijk van ons naar achteren verschoven (in parallel), of varieerde de plaatsing van wervel tot wervel.
Afropithecus (~16 Ma) geleek op Morotopithecus, lag ook bij waterdwerghertjes, varieerde ook sterk in gewicht, had een erg lang gelaat, zoals sommige veel vroegere en kleinere Fayyūm-apen (Aegyptopithecus, Saadanius), met ondiep verhemelte, grote, brede, spatelvormige, vooruitstekende bovensnijtanden, de middenste veel groter dan de tweede (zoals bij orangs), rechthoekige tandenboog en heel forse kiezen met nogal dik gerimpeld glazuur en afgeronde knobbels (bunodont). Hun sterke hoektanden waren saki-achtig (sclerocarp): kraakten ze harde vruchtdoppen? Hun ovale oogkassen, stevig omrand, stonden opvallend uiteen: hielpen grote neusholtes hun ogen, mond en neusgaten boven water? Ze leken nog vooral boventakkers, met forse grijphanden, volgens sommigen in tropische bossen met bladverlies in het droge seizoen. De iets kleinere ‘Saudi Ape’ (Helio- of Afropithecus leakeyi 18 of 17 Ma) lag in tropische kustafzettingen van de zuidelijke Tethys, nu de Perzische Golf.

This is just stupid.

Bipedalism is older than the LCA. You're claiming that the same
environment that spawned bipedalism also destroyed it.

Why? Explain this massive contradiction that makes you look
stupid.

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https://jtem.tumblr.com/post/717065307257176065