Archaehierax sylvestris gen. et sp. nov. (1 Viewer)

[Fred Ruhe]

Ellen K. Mather, Michael S. Y. Lee, Aaron B. Camens & Trevor H. Worthy, 2021

An exceptional partial skeleton of a new basal raptor (Aves: Accipitridae) from the late Oligocene Namba formation, South Australia

Historical Biology: An International Journal of Paleobiology. Online edition. doi:10.1080/08912963.2021.1966777

Abstract: https://www.tandfonline.com/doi/full/10.1080/08912963.2021.1966777?scroll=top&needAccess=true

The Australian pre-Pleistocene fossil record of Accipitridae (eagles, hawks, old-world vultures) comprises one latest Oligocene or early Miocene and one middle Miocene species, each represented by partial bones. Globally, most fossil accipitrids are based on single bones. The recent discovery of an older and considerably more complete accipitrid from late Oligocene sediments in Australia is therefore significant. It is derived from the Pinpa Local Fauna from the Namba Formation at Lake Pinpa, South Australia (~26–24 Ma). The fossil, described as Archaehierax sylvestris gen. et sp. nov., represents a raptor that was larger than the black-breasted buzzard Hamirostra melanosternon but smaller and more gracile than the wedge-tailed eagle Aquila audax. Comprehensive morphological and molecular phylogenetic analyses resolved Archaehierax as a basal accipitrid, not closely related to any living subfamily and perhaps the sister taxon to all other accipitrids exclusive of elanines. Relatively short wings similar to species of Spizaetus and Spilornis suggest it was adapted for flight within enclosed forests. Additional accipitrid fossils from the Namba Formation, a distal femur and a distal humerus, are incomparable with the holotype of A. sylvestris; they may represent distinct species or smaller individuals of the new taxon. lsid:zoobank.orgub:6A25C569-3E9F-43B8-AAF8-F36CE405C06E

Also a new subfamily is named: Subfamily: Archaehieraxinae subfam. nov.

Free pdf: https://www.tandfonline.com/doi/epub/10.1080/08912963.2021.1966777?needAccess=true

Enjoy,

Fred

 

[Fred Ruhe]

Systematic palaeontology

Class Aves Linnaeus, 1758
Order Accipitriformes Vieillot 1816
Family Accipitridae Vigors, 1824
Subfamily Archaehieraxinae subfam. nov.
Type genus: Archaehierax gen. nov.

Remarks
The fossil is identified as an accipitrid due to the following combination of characters: Skull – Rostrum deep and narrow, with hooked tip and a large, broad nasal aperture; Tibiotarsus – Pons supratendineus ossified, aligned steeply transversely, medially placed, with unbranched canalis tendinosus, and distal condyles much wider than craniocaudally deep; Tarsometatarsus – Robust, with monosulcate hypotarsus, the lateral and medial hypotarsal crests widely separated and trochleae metatarsorum splayed both medially and laterally, and dorsally arched in distal view; Foot – Four digits with raptorial unguals, those of digits 1 and 2 relatively large; Digit IV – phalanges 2 and 3 are very short compared to phalanx 4. The fossil can be excluded from Falconiformes Falconidae) and the other families of Accipitriformes (Cathartidae, Sagittariidae,
Pandionidae) by the morphology of the tarsometatarsal hypotarsus cristae and sulcus. The cristae are fused or partially fused together to enclose the sulcus in Cathartidae, Sagittariidae, and Pandionidae, while in Falconidae the medial crista is connected to the shaft by a ridge that extends two-thirds of its length, features that are absent in the fossil.

Diagnosis
Accipitrids in which the following autapomorphic features are found: the pila medialis of the sternum dorsally separates two deep pneumatic fossae, the humerus has the caput humeri only slightly elevated proximally past the tuberculum ventralis, the tip of the processus procoracoideus of the coracoid sharply curves inwards ventrally towards the medial face of the bone, the tibiotarsus has the lateral/distal retinaculum scar in a deep fossa, the tarsometatarsus is relatively elongate with narrow trochleae metatarsorum that are separated by wide incisurae, and the incisura for the m. flexor hallucis brevis tendon is large, distinct, and extends distal to the fossa metatarsi I. In addition to this, the following features occur: the rostral tip of the rostrum is hooked below the tomial margin at a relatively shallow 30–40° angle, the quadrate has a deep, distinct foramen pneumaticum caudomediale, and the sternum has the apex carinae displaced caudally from the base of the spina externa.,

Genus Archaehierax Mather, Lee, Camens and Worthy gen. nov.

Type species: Archaehierax sylvestris sp. nov.

http://zoobank.org/urn:lsid:zoobank.org:act:8C4B01F2-12CE-

46F4-A444-C63B18C90BAE

Etymology
Archaehierax is derived from the Greek words ‘archaios’, meaning
ancient, and ‘hierax’, meaning hawk. Gender masculine.

Diagnosis
An accipitrid distinguished by the combination of the following features; Rostrum. (1) The nares are large and fully open, (2) processus maxillopalatini not fused; Quadrate. (3) the condylus pterygoideus projects less medially than the condylus medialis, (4) a deep, distinct fossa caudomedialis with a small amount of pneumatism; Sternum. (5) The apex carinae is displaced caudally from the base of the spina externa, (6) the medial crista on the carina does not extend to the spina externa; (7) The pila medialis on the dorsal face separates two deep fossae (autapomorphy); Humerus. (8) The caput humeri is only slightly elevated proximally past the tuberculum ventralis (autapomorphy); Os carpale ulnare. (9) Deepened depression on ulnaris face; Tarsometatarsus. (10) The trochleae metatarsorum are splayed and separated by wide incisurae, especially laterally, with the individual trochleae themselves quite narrow in width (autapomorphy); (11) The incisura for the m. flexor hallucis brevis tendon is large, distinct, and extends distal to the fossa metatarsi I (autapomorphy); Phalanx IV.4. (12) The distal articular end that articulates with phalanx IV.5, is considerably wider than the shaft.

Type Locality/Stratigraphy/Age
31° 07.499ʹ S; 140° 12.755ʹ E. Site 12a, Lake Pinpa, Frome Downs Station, Callabonna Sub-Basin, S.A. Dolomite bed of Namba Formation, Pinpa LF, late Oligocene, 26–24 Ma.

Archaehierax sylvestris Mather, Lee, Camens and Worthy gen. et sp. nov.

ZooBank.org

Holotype
SAMA P.54998, 63 elements and associated fragments of a single skeleton as follows: Fragments of mandible; rostral majority of rostrum; R pterygoid; L quadratojugal; L quadrate; ceratohyal; atlas vertebra; axis vertebra; partial cervical vertebra #3; caudal vertebrae x3 (position in tail indeterminate); cranial part sternum; LR scapulae; cranial and sternal parts LR coracoids; proximal LR humeri; L and distal R ulna; L and distal R radius; L carpometacarpus; LR os carpi ulnare; L os carpi radiale; R manual phalanges, proximal fragment MI.1, proximal fragment MII.1 and MII.2; L manual phalanges MI.1, MII.2 with distal end eroded, and MIII.1; LR proximal femur fragments; R tibiotarsus reconstructed in two parts; L tibiotarsus; fragmented LR fibulae; LR tarsometatarsi; LR ossa metatarsalia; pedal phalanges: RI.1, RII.1, RII.2, RIII.1, RIII.2, RIII.3 (partial), RIII.4, LI.1, LI.2 (fragmented), LII.1, LII.2, LIII.1,
LIII.2, LIII.3 (partial), LIII.4, LIV.1, LIV.2, LIV.3, LIV.4, LIV.5. The skeleton was found eroding out on the surface with surviving elements recovered in a semi-articulated state from within dolomitic clays (equivalent to layer 5 of Thorn et al. 2021), with most large elements fractured into many roughly articulated pieces, presumably by expansion and contraction associated with the wetting and drying of the clays. The fragments for each element were, where possible, separated, cleaned and reassembled by THW.

Etymology
The species name ‘sylvestris’ is derived from the Greek word ‘sylvas’, meaning forest, and the Latin suffix ‘-estris’, meaning ‘belonging to’.

Type locality/Stratigraphy and age
As per genus.

Diagnosis
As for genus.

Fred


Figure 1. Exemplar accipitriform skeleton, Pandion haliaetus cristatus, derived from an illustration in Eyton (1867), showing the bones preserved in the fossil accipitrid specimen SAMA P.54998 shaded in grey. The illustrated taxon and fossil material are not identical in terms of the morphology of individual elements.

Figure 2. Archaehierax sylvestris gen. et. sp. nov. SAMA P.54998 partial sternum in cranial (A), left lateral (B) and dorsal (C) view; right scapula in lateral (D) and medial (E) view; omal fragments of the left coracoid in medial (F) and lateral (H) view and of the right coracoid in dorsal (G) and medial (I) view. Specimens in A, B, and F-I are coated in ammonium chloride. Abbreviations: AC, apex carina; Ac, acromion; MC, crista medialis carinae; CtS, cotyla scapularis; ColS, collum scapulae; FAC, facies articularis clavicularis; FAH, facies articularis humeralis; FoNS, foramen nervi supracoracoidei; ILA, impressio ligamenti acrocoracohumeralis; LI, labrum internum; MD, margo dorsalis; PC, pila carinae; PM, pila medialis; P. Procor., processus procoracoideus; SAC, sulcus articularis coracoideus; SE, spina externa; SMS, sulcus m. supracoracoidei; TC, tuberculum coracoideum. Scale bars are 10 mm.

Figure 3. Analysis 4a: combined molecular and morphological data (ordered) analysed with Bayesian methods; molecular and orphological partition branch lengths unlinked. Node values show posterior probability.

 

[l_raty]

The species name ‘sylvestris’ is derived from the Greek word ‘sylvas’, meaning forest, and the Latin suffix ‘-estris’, meaning ‘belonging to’.

FWIW, the Latin adjective sylvestris is a variant spelling of the Latin adjective silvestris, belonging to a forest, itself formed from the Latin noun silva ("less correctly sylva"), forest, and the Latin adjectival suffix -estris, belonging to.

(There is no "Greek word ‘sylvas’, meaning forest". In fact, one would even struggle seriously to simply write "sylvas" in Ancient Greek, because the alphabet had no letter equivalent to v.)

 

[Fred Ruhe]

Family Accipitridae Vigors, 1824
Subfamily indet. Gen. et sp. indet.

Material
Distal right humeral fragment, preserving a relatively unworn distal end and 16.2 mm of shaft, and some associated fragments of the shaft, SAMA P.58917.

Locality, stratigraphy and age
31° 07.568ʹ S; 140° 12.737ʹ E. Site 11, Lake Pinpa, Frome Downs Station, South Australia, Namba Formation, Pinpa LF, late Oligocene. Collected by A. Camens, T. Worthy and W. Handley, 24–26 September 2015.

Fred


Figure 4. Accipitrid distal right humerus SAMA P.58917 in cranial (A), caudal (B), dorsal (C) and ventral (D) view. Abbreviations: CD, condylus dorsalis; CDCS, condylus dorsalis caudal scars; CV, condylus ventralis; EV, epicondylus ventralis; FB, fossa brachialis; FO, fossa olecrani; II, incisura intercondylaris; MECR, m. extensor carpi radialis insertion scars; MFCUS, musculus flexor carpi ulnaris scars; PF, processus flexorius; PSD, tuberculum supracondylare dorsale; PSI, pronator superficialis insertion; SHT, sulcus humerotricipitalis; SST, sulcus scapulotricipitalis; TSV, tuberculum supracondylare ventrale. Scale bar 10 mm.

 

[Fred Ruhe]

Family Accipitridae Vigors, 1824
Subfamily indet. Gen. et sp. indet.

Material
NMV P.222435, distal left femur preserving intact distal end and 15.5 mm of shaft.

Locality, stratigraphy and age
31° 11.237’S 140° 13.944ʹE Ericmas Quarry, Lake Namba, Frome Downs Station, South Australia, Namba Formation, Ericmas LF, late Oligocene. Collected by T. Flannery, 7/4/83.

Fred


Figure 5. Distal left femur NMV P.222435 depicted in cranial (A), caudal (B), medial (C) and lateral (D) view. Abbreviations: CM, condylus medialis; EL, epicondylus lateralis; FPop, fossa poplitea; IG, impressio m. mastrocnemialis lateralis; ILCC, impressio lig. cruciati cranialis; LIC, linea intermuscularis caudalis; PPAP, planum popliteum attachment point; SP, sulcus patellaris; TF, trochlea fibularis; TMGM, tuberculum muscularis gastrocnemialis medialis. Scale bar 10 mm.