Cryptogyps Mather, Lee and Worthy 2022 gen. nov. (1 Viewer)

[Fred Ruhe]

Ellen K. Mather, Michael S. V. Lee & Trevor H. Worthy, 2022

A new look at an old Australian raptor places “Taphaetus” lacertosus de Vis 1905 in the Old World vultures (Accipitridae: Aegypiinae)

Zootaxa: 1–23.
doi:10.11646/zootaxa.5168.1.1

Abstract and free pdf: A new look at an old Australian raptor places “ Taphaetus ” lacertosus de Vis 1905 in the Old World vultures (Accipitridae: Aegypiinae) | Zootaxa

The Australian Pleistocene fossil record of the Accipitridae (hawks, eagles and Old World vultures) is sparse and poorly known. Only two extinct confirmed accipitrid species have been described for this time period; both have received little investigation since their description. One is “Taphaetus” lacertosus de Vis, 1905, described from a distal humerus and a quadrate from north-eastern South Australia. While this species was verified as an accipitrid in subsequent studies, its more precise taxonomic affinities have remained conjectural. In this study, a new analysis incorporating newly referred material and phylogenetic analyses using a wide range of accipitriforms reveals that the lectotype humerus of “T.” lacertosus is an Old World vulture in the subfamily Aegypiinae. The associated quadrate, one of two original syntypes from which de Vis named this species, is of an indeterminate species of ardeid. We erect the novel genus Cryptogyps, to accommodate the species ‘lacertosus’, as it cannot be placed in Taphaetus de Vis, 1891, because the type species of this genus, Uroaetus brachialis de Vis, 1889, was transferred back to the genus Uroaetus, a synonym of Aquila Brisson, by de Vis in 1905. Further, U. brachialis is now considered a synonym of Aquila audax (Latham, 1801). Moreover, Taphaetus de Vis, 1891 is a senior homonym of Taphaetus de Vis, 1905, type species Taphaetus lacertosus de Vis, 1905, making the 1905 version of the genus unavailable. Newly referred fossils from Wellington Caves (NSW) and the Nullarbor Plains (WA) reveal this taxon had a wide geographical range across Pleistocene Australia. The referred tarsometatarsus lacks hyper-developed trochleae, indicating that Cryptogyps lacertosus (de Vis, 1905) comb. nov., was probably a scavenger like other aegypiines. Identification of Cryptogyps lacertosus as an aegypiine significantly expands the palaeogeographical range of the Old World vultures, hitherto unknown in Australia. The avian guild of large, obligate scavenging birds of prey, is currently absent in the modern Australian biota, but its former presence is not surprising given the megafauna-rich communities of the Pleistocene.

Enjoy,

Fred

 

[Fred Ruhe]

Systematic Palaeontology

Accipitriformes Vieillot, 1816
Accipitridae Vigors, 1824
The lectotype of ‘Taphaetus’ lacertosus de Vis, 1905, a distal right humerus, QM F5507, is identified as an accipitrid based on the presence of the following characters: The distal margin of the fossa brachialis extends distal to the tuberculum supracondylare dorsale; a distinct sulcus scapulotricipitalis; the proximal margin of the condylus dorsalis is roughly level with the ventral tip of the epicondylus ventralis; a distinct circular dorsal insertion for the m. extensor metacarpi radialis on the dorsal projection of the tuberculum supracondylare dorsale; a distinct pit for the insertion of the m. pronator superficialis ventrally adjacent to and slightly proximal to the tuberculum supracondylare ventrale; and the epicondylus ventralis is markedly ventrally prominent.
This fossil is readily distinguished from the following similar-sized birds likely to be encountered in Pleistocene Australian fossil sites.

• From Ciconiidae (Ephippiorhynchus asiaticus) by the following characters (ciconiid state in brackets): The tuberculum supracondylare dorsale is strongly projecting (little to no projection); the dorsal sulcus of the m. humerotricipitalis is narrow, just under a third of the shaft width (broad, roughly half the shaft width); the ventral sulcus of the m. humerotricipitalis is broad, twice the width of the dorsal sulcus (narrow, half the width); the epicondylus ventralis and the tuberculum supracondylare ventrale are distinctly separated from each other (continuous/overlapping); the dorsal insertion of the m. extensor metacarpi radialis is oval restricted to the dorsal facies (circular with a ventrally projecting line leading onto the cranial facies).
• From Pelecanidae (Pelecanus conspicillatus) by the following characters (pelecanid state in brackets): The tuberculum supracondylare dorsale is strongly projecting (little to no projection); the origin of m. extensor digitorum communi is a small, circular pit on the dorsal facies between the tuberculum supracondylare dorsale and the epicondylus dorsalis (large, oval-shaped attachment scar); the tuberculum supracondylare ventrale is weakly projecting cranially (cranially flattened); there is no pneumatism of the distal end (pneumatic region present on cranial facies adjacent to tuberculum supracondylare ventrale); the epicondylus ventralis strongly projects ventrally (weak projection); the distal margin of the fossa brachialis is positioned distal to the tuberculum supracondylare dorsale (positioned proximal to the processus).
• From Phoenicopteriformes (Phoenicopterus ruber) by the following characters (phoenicopterid state in brackets): the epicondylus ventralis projects prominently ventrally (little to no projection), the dorsal sulcus for the m. humerotricipitalis is under a third of the shaft width (half of shaft width), the ventral sulcus for the m. humerotricipitalis is twice the width of the dorsal sulcus (half the width of the dorsal sulcus), the tuberculum supracondylare ventrale is weakly projecting cranially (cranially flattened), the condylus dorsalis and condylus ventralis are separated by a distinct, deep incisura (narrow, shallow incisura).
• From Ardeidae by the following characters (ardeid state in brackets): A deep fossa m. brachialis (shallow); a broad fossa m. brachialis, approximately two thirds of shaft width or more (narrow, one third of shaft width); a narrow sulcus for the dorsal belly of the m. humerotricipitalis (broad).

Several features of the bone, notably its large size, are only matched by Aquila audax and Haliaeetus leucogaster in the Australian fauna. However, the combination of a narrow dorsal part of sulcus humerotricipitalis, a markedly prominent epicondylus ventralis, the dorsally inflated facies between the tuberculum supracondylare dorsale and the epicondylus dorsalis, and a distally short processus flexorius, distinguish it from all other accipitrids. As this humerus is unambiguously identifiable as that of an accipitrid and is distinguished from all known genera and species, ‘Taphaetus’ lacertosus is confirmed as a distinct taxon. However, it requires a new genus, as Taphaetus de Vis, 1905 is a junior homonym of Taphaetus de Vis, 1891, and the latter is a junior synonym of Uroaetus Kaup, 1844 and so of Aquila Brisson, 1760.
As the quadrate QM F5508 was inaccessible at the time of this study, we instead used the descriptions and illustrations in de Vis (1905) to assess if the original identification was valid. QM F5508 differs distinctly from quadrates of accipitrids, instead being similar to those of Ardeidae, particularly species in the genera Ardea and Egretta, by the following characters (accipitrid state in brackets): A large foramen pneumaticum caudomediale is positioned ventral to the capitulum oticum articular surface (no foramen pneumaticum, though a depressio caudomediale is present in some species); the capitulum oticum is positioned further dorsally relative to the capitulum squamosum (capitulum squamosum further dorsal); the width of the capitula and the width of the shaft are very similar, with little narrowing between the dorsal and ventral ends (shaft distinctly narrower than dorsal end); in caudal view, the condylus mandibularis medialis is positioned level with the condylus mandibularis lateralis, with both being equally visible (condylus mandibularis medialis set back rostrally, less visible than the condylus lateralis); the condylus mandibularis caudalis is prominently projecting caudally (projecting medially); the condylus mandibularis lateralis barely extends laterally from the shaft (extends prominently caudally); the condylus mandibularis medialis extends prominently medially from the shaft (little to no extension); a prominent secondary facet is present on the condylus mandibularis medialis (no secondary facet); in ventral view, the condyles project rostrally past the rostral margin of the articular surface (roughly in line with margin). The reported dorsal height of 22 mm is distinctly larger than that observed in the Australasian Bittern Botaurus poiciloptilus (~15–16 mm). While the morphology of QM F5508 is a better match for a heron, it is much larger than compared specimens of White-faced Heron Egretta novaehollandiae and Grey Heron Ardea cinerea but could potentially be a match in size to that of the Great-billed Heron (Ardea sumatrana). As QM F5508 is not of an accipitrid, it is not considered further here.

 

[Fred Ruhe]

Cryptogyps Mather, Lee and Worthy 2022 gen. nov.

ZooBank.org

Type species: ‘Taphaetus’ lacertosus de Vis, 1905: Annals of the Queensland Museum.

Etymology: The name is derived from a combination of the Ancient Greek words ‘kryptós’ (hidden) and ‘gýps’ (vulture), in reference to the fact that this taxon was known for over 100 years but was generally believed to be an eagle. Cryptogyps also relates to the word ‘crypt’, a word used to describe an underground burial chamber, referencing the discovery of the new material in caves.

Revised diagnosis: A large accipitrid, similar in size to Aquila audax, with humeri differing from all other Accipitridae by the following combination of characters: (1) a prominent dorsal convexity of the facies between the tuberculum supracondylare dorsale and the epicondylus dorsalis; (2) a strongly dorsally projecting tuberculum supracondylare dorsale; (3) a distinct and deepened attachment for the origin of m. extensor digitorum communi; (4) a large, shallow, circular attachment scar for the origin of the proximal head of m. pronator superficialis (=pronator brevis); (5) the epicondylus ventralis is strongly projected ventrally as a craniocaudally elongate peak; (6) the processus flexorius is distally short, ending proximal to the distal margin of the condylus ventralis; (7) and it has a narrow sulcus/groove for the dorsal belly of the m. humerotricipitalis.

Cryptogyps lacertosus (de Vis, 1905) comb. nov.
Synonyms:
Taphaetus lacertusus De Vis, 1905.
Aquila lacertosa (De Vis, 1905).
Uroaetus lacertosus (De Vis, 1905).
Ichthyophaga lacertosa (De Vis, 1905)

Lectotype: QM F5507, distal R humerus (designated by van Tets, 1974, p. 58).

Type locality: Kalamurina, Warburton River, Kati Thanda–Lake Eyre Basin, SA. Collected by John W. Gregory in April 1902 (de Vis 1905).

Stratigraphy and Geological age: Katipiri Formation; mid- to late Pleistocene; the fossils are assumed to have derived from fluvial sediments that outcrop in the banks of the river at this point. The associated fauna comprises the Kalamurina Fauna and is typical of the late Pleistocene (Tedford & Wells 1990; Tedford et al. 1992).

Measurements (mm) of QM F.5507: preserved distal width 35.5, lateromedial width of the condylus dorsalis 9.1, depth of the condylus dorsalis 22.3, proximodistal length of the condylus dorsalis 12.3, width of the condylus ventralis 14.1.

Amended diagnosis: As for genus.

Newly referred material
Localities and age: Leaena’s Breath Cave, Nullarbor, WA, Australia, 31.4°S 128.1°E; excavation Pit B1, Unit 3, depth 115–120 cm; Pleistocene; collected by G. Prideaux et al. 2013, identified as an accipitrid by Shute (2018): WAM 15.9.73 proximal left tarsometatarsus.
‘Old Collection’, Wellington Caves, NSW, Australia, 32°31’ S, 148°51’ E; Pleistocene; likely acquired by NSW Mining Department 1884–1917: AM F.58093, left tarsometatarsus; AM F.58092, distal right and left humeri. The new material has been assigned to Cryptogyps lacertosus for the following reasons: The two distal humeri fragments AM F.58092 are a similar size to (see Table 1) and have identical morphology to the lectotype QM F5507, and so are unambiguously referred to this same species. Specifically, these two fragments show the same unique sharp ventrally projecting entepicondyle and the same distally abbreviated processus flexorius.

Fred


Figure 1. Comparisons of the distal humeri of Cryptogyps lacertosus QM F5507 (scanned, A, D, G), Aquila audax (B, E, H) and Haliaeetus leucogaster (C, F, I) in cranial (A, B, C), caudal (D, E, F) and ventral (G, H, I) view. Abbreviations: CD, condylus dorsalis; CV, condylus ventralis; DEMR, dorsal attachment m. extensor metacarpi radialis; ED, epicondylus dorsalis; EV, epicondylus ventralis; FB, fossa brachialis; FO, fossa olecrani; II, incisura intercondylaris; MeDCo, m. extensor digitorum communi origin; MPSO, origin of distal head of m. pronator superficialis; MPPO, m. pronator profundus origin; PF, processus flexorius; PEMR, palmar attachment m. extensor metacarpi radialis; SHTD, dorsal sulcus humerotricipitalis; SHTV, ventral sulcus humerotricipitalis; SST, sulcus scapulotricipitalis; TSD, tuberculum supracondylare dorsale; TSV, tuberculum supracondylare ventrale. Scale bar 10 mm.