The pectoral girdle of StW 573 (‘Little Foot’) and its mplications for hominin evolution
KRISTIAN J CARLSON cs 2021 AAPA

The c 3.67-Ma adult skeleton Little Foot StW 573 (Sterkfontein
Member 2 breccia, Silberberg Grotto) is remarkable for its morphology & completeness.
Clavicles & scapulae of StW 573 offer opportunities to assess morphological & functional aspects of a nearly complete apith pectoral girdle.
It combines features intermediate between Hs & other African apes:
- a long & infero-medially-inflected clavicle, suggesting a rel.high & dorsally-positioned scapula,
- enlarged supraspinous fossa size & shape,
- a rel.cranially-oriented glenoid fossa,
- non-human, ape-like reinforcement of the axillary margin by a stout ventral bar.
The StW 573 scapulae are
- smaller than those of some apiths (e.g. KSD-VP-1/1, KNM-ER 47000A),
- larger than others (e.g. AL-288-1, Sts 7, MH 2).
The StW 573 scapula is similar in size to the apith StW 431 partial scapula, and also shares similar structure along its axillary margin & inferior angle.

Overall, morphology of the StW 573 pectoral girdle presents numerous features that are selectively advantageous for arboreal positional behaviors,
but rel.fewer of the derived adaptations toward manipulatory function that have been attributed to pene-contemporaneous representatives of Au.afarensis (i.e. KSD-VP-1/1).
Considering morphologies of incomplete pectoral girdles from middle/late Miocene apes & consensus views on the adaptiveness of arboreal positional behaviors incorporating abducted gleno-humeral joints in early Pliocene hominins, we hypothesize that the StW 573 pectoral girdle configuration is a reasonable model for the human-Afr.ape LCA.

(IOW this once more confirms our view that S.Afr.apiths almost 4 Ma (cf H/P split c 5 Ma?) were
- still aquarboreal (google),
- already closer anatomically to Pan than to Homo --mv)

On 26.7.2021. 0:48, littor...@gmail.com wrote:
> The pectoral girdle of StW 573 (‘Little Foot’) and its mplications for hominin evolution
> KRISTIAN J CARLSON cs 2021 AAPA
>
> The c 3.67-Ma adult skeleton Little Foot StW 573 (Sterkfontein
> Member 2 breccia, Silberberg Grotto) is remarkable for its morphology & completeness.
> Clavicles & scapulae of StW 573 offer opportunities to assess morphological & functional aspects of a nearly complete apith pectoral girdle.
> It combines features intermediate between Hs & other African apes:
> - a long & infero-medially-inflected clavicle, suggesting a rel.high & dorsally-positioned scapula,
> - enlarged supraspinous fossa size & shape,
> - a rel.cranially-oriented glenoid fossa,
> - non-human, ape-like reinforcement of the axillary margin by a stout ventral bar.
> The StW 573 scapulae are
> - smaller than those of some apiths (e.g. KSD-VP-1/1, KNM-ER 47000A),
> - larger than others (e.g. AL-288-1, Sts 7, MH 2).
> The StW 573 scapula is similar in size to the apith StW 431 partial scapula, and also shares similar structure along its axillary margin & inferior angle.
>
> Overall, morphology of the StW 573 pectoral girdle presents numerous features that are selectively advantageous for arboreal positional behaviors,
> but rel.fewer of the derived adaptations toward manipulatory function that have been attributed to pene-contemporaneous representatives of Au.afarensis (i.e. KSD-VP-1/1).
> Considering morphologies of incomplete pectoral girdles from middle/late Miocene apes & consensus views on the adaptiveness of arboreal positional behaviors incorporating abducted gleno-humeral joints in early Pliocene hominins, we hypothesize that the StW 573 pectoral girdle configuration is a reasonable model for the human-Afr.ape LCA.
>
> (IOW this once more confirms our view that S.Afr.apiths almost 4 Ma (cf H/P split c 5 Ma?) were
> - still aquarboreal (google),
> - already closer anatomically to Pan than to Homo --mv)

Hm, it isn't "closer anatomically", it has pectoral girdle adjusted
for over-head climbing (just like you can see it in one species of Homo,
Homo naledi). If it has feet, hands, and fingers like humans, it isn't
"anatomically closer" to chimps. Feet, hands and fingers are of much
higher importance in determining the locomotor abilities.

--
https://groups.google.com/g/human-evolution
human-evolution@googlegroups.com

On 26.7.2021. 4:33, Mario Petrinovic wrote:
> On 26.7.2021. 0:48, littor...@gmail.com wrote:
>> The pectoral girdle of StW 573 (‘Little Foot’) and its mplications for
>> hominin evolution
>> KRISTIAN J CARLSON cs 2021 AAPA
>>
>> The c 3.67-Ma adult skeleton Little Foot StW 573 (Sterkfontein
>> Member 2 breccia, Silberberg Grotto) is remarkable for its morphology
>> & completeness.
>> Clavicles & scapulae of StW 573 offer opportunities to assess
>> morphological & functional aspects of a nearly complete apith pectoral
>> girdle.
>> It combines features intermediate between Hs & other African apes:
>> - a long & infero-medially-inflected clavicle, suggesting a rel.high &
>> dorsally-positioned scapula,
>> - enlarged supraspinous fossa size & shape,
>> - a rel.cranially-oriented glenoid fossa,
>> - non-human, ape-like reinforcement of the axillary margin by a stout
>> ventral bar.
>> The StW 573 scapulae are
>> - smaller than those of some apiths (e.g. KSD-VP-1/1, KNM-ER 47000A),
>> -  larger than others (e.g. AL-288-1, Sts 7, MH 2).
>> The StW 573 scapula is similar in size to the apith StW 431 partial
>> scapula, and also shares similar structure along its axillary margin &
>> inferior angle.
>>
>> Overall, morphology of the StW 573 pectoral girdle presents numerous
>> features that are selectively advantageous for arboreal positional
>> behaviors,
>> but rel.fewer of the derived adaptations toward manipulatory function
>> that have been attributed to pene-contemporaneous representatives of
>> Au.afarensis (i.e. KSD-VP-1/1).
>> Considering morphologies of incomplete pectoral girdles from
>> middle/late Miocene apes & consensus views on the adaptiveness of
>> arboreal positional behaviors incorporating abducted gleno-humeral
>> joints in early Pliocene hominins, we hypothesize that the StW 573
>> pectoral girdle configuration is a reasonable model for the
>> human-Afr.ape LCA.
>>
>> (IOW this once more confirms our view that S.Afr.apiths almost 4 Ma
>> (cf H/P split c 5 Ma?) were
>> - still aquarboreal (google),
>> - already closer anatomically to Pan than to Homo  --mv)
>
>         Hm, it isn't "closer anatomically", it has pectoral girdle
> adjusted for over-head climbing (just like you can see it in one species
> of Homo, Homo naledi). If it has feet, hands, and fingers like humans,
> it isn't "anatomically closer" to chimps. Feet, hands and fingers are of
> much higher importance in determining the locomotor abilities.

Oh, and what about the pelvis? This thing is a complete human, and, if
you start with default primate skeleton, it is obvious that Apiths move
into human, and not into chimp direction. If for the pelvis alone. Our
pelvis is unique, and as such it is the prime indicator.

--
https://groups.google.com/g/human-evolution
human-evolution@googlegroups.com

Op maandag 26 juli 2021 om 00:48:08 UTC+2 schreef littor...@gmail.com:

> The pectoral girdle of StW 573 (‘Little Foot’) and its mplications for hominin evolution
> KRISTIAN J CARLSON cs 2021 AAPA
> The c 3.67-Ma adult skeleton Little Foot StW 573 (Sterkfontein
> Member 2 breccia, Silberberg Grotto) is remarkable for its morphology & completeness.
> Clavicles & scapulae of StW 573 offer opportunities to assess morphological & functional aspects of a nearly complete apith pectoral girdle.
> It combines features intermediate between Hs & other African apes:
> - a long & infero-medially-inflected clavicle, suggesting a rel.high & dorsally-positioned scapula,
> - enlarged supraspinous fossa size & shape,
> - a rel.cranially-oriented glenoid fossa,
> - non-human, ape-like reinforcement of the axillary margin by a stout ventral bar.
> The StW 573 scapulae are
> - smaller than those of some apiths (e.g. KSD-VP-1/1, KNM-ER 47000A),
> - larger than others (e.g. AL-288-1, Sts 7, MH 2).
> The StW 573 scapula is similar in size to the apith StW 431 partial scapula, and also shares similar structure along its axillary margin & inferior angle.
> Overall, morphology of the StW 573 pectoral girdle presents numerous features that are selectively advantageous for arboreal positional behaviors,
> but rel.fewer of the derived adaptations toward manipulatory function that have been attributed to pene-contemporaneous representatives of Au.afarensis (i.e. KSD-VP-1/1).
> Considering morphologies of incomplete pectoral girdles from middle/late Miocene apes & consensus views on the adaptiveness of arboreal positional behaviors incorporating abducted gleno-humeral joints in early Pliocene hominins, we hypothesize that the StW 573 pectoral girdle configuration is a reasonable model for the human-Afr.ape LCA.

> (IOW this once more confirms our view that S.Afr.apiths almost 4 Ma (cf H/P split c 5 Ma?) were
> - still aquarboreal (google),
> - already closer anatomically to Pan than to Homo --mv)

Reconstruction of Homo/Pan LCA:
mostly a mozaic of human & bonobo features, generally gracile apith-like:
-brain c 400 cc
-full plantigrady, more humanlike feet
-no knuckle-walking
-orthograde (aquarboreal)
-no external nose
-very broad pelvis + very flaring ilia (femoral abduction)
-no very long arms
-no very long legs
-+-thick enamel
-no very long canines
-...

(google "aquarboreal")

littor...@gmail.com wrote:
> The pectoral girdle of StW 573 (‘Little Foot’) and its mplications for hominin evolution

Incorrect title. couldn't you even get that right?

> KRISTIAN J CARLSON cs 2021 AAPA

This was posted in April.

Here is the link and REAL abstract, not what you made up.

https://www.sciencedirect.com/science/article/pii/S004724842100035X

The pectoral girdle of StW 573 (‘Little Foot’) and its implications for
shoulder evolution in the Hominina

Abstract
The ca. 3.67 Ma adult skeleton known as ‘Little Foot’ (StW 573), recovered
from Sterkfontein Member 2 breccia in the Silberberg Grotto, is remarkable
for its morphology and completeness. Preservation of clavicles and
scapulae, including essentially complete right-side elements, offers
opportunities to assess morphological and functional aspects of a nearly
complete Australopithecus pectoral girdle. Here we describe the StW 573
pectoral girdle and offer quantitative comparisons to those of extant
hominoids and selected homininans. The StW 573 pectoral girdle combines
features intermediate between those of humans and other apes: a long and
curved clavicle, suggesting a relatively dorsally positioned scapula; an
enlarged and uniquely proportioned supraspinous fossa; a relatively
cranially oriented glenoid fossa; and ape-like reinforcement of the
axillary margin by a stout ventral bar. StW 573 scapulae are as follows:
smaller than those of some homininans (i.e., KSD-VP-1/1 and KNM-ER
47000A), larger than others (i.e., A.L. 288-1, Sts 7, and MH2), and most
similar in size to another australopith from Sterkfontein, StW 431.
Moreover, StW 573 and StW 431 exhibit similar structural features along
their axillary margins and inferior angles. As the StW 573 pectoral girdle
(e.g., scapular configuration) has a greater affinity to that of
apes—Gorilla in particular—rather than modern humans, we suggest that the
StW 573 morphological pattern appears to reflect adaptations to arboreal
behaviors, especially those with the hand positioned above the head, more
than human-like manipulatory capabilities. When compared with less
complete pectoral girdles from middle/late Miocene apes and that of the
penecontemporaneous KSD-VP-1/1 (Australopithecus afarensis), and mindful
of consensus views on the adaptiveness of arboreal positional behaviors
soliciting abducted glenohumeral joints in early Pliocene taxa, we propose
that the StW 573 pectoral girdle is a reasonable model for hypothesizing
pectoral girdle configuration of the crown hominin last common ancestor.

"The constellation of features exhibited by the StW 573 pectoral girdle
suggests an upper limb, specifically the scapulothoracic and glenohumeral
joints,
functioning during a diverse behavioral repertoire that involved
substantial weight-bearing at times. Cranial, pelvic, and lower limb
adaptations evident in StW 573 clearly indicate the
importance of orthogrady and bipedal locomotor modes (Clarke and Kuman,
2019; Heaton et al., 2019), likely constraining upper limb weight-bearing
activities to arboreal positional modes.

"Wrist and hand elements of the StW 573 skeleton
also exhibit signs of strong selective pressures favoring arboreal
behavior, e.g., a strongly developed digital flexor apparatus and
curved proximal phalanges (Jashashvili et al., in review). The
presence of these features in StW 573 at ca. 3.67 Ma and the
persistence of some in MH2 at ca.1.98 Ma may indicate that in some
australopith lineages selective pressures favoring below branch
suspensory activities may have continued for quite some time."

Nice video of the reconstruction process

https://www.youtube.com/watch?v=lVbg_5Z_9Vk