Allgoviachen tortonica n. gen. et sp. (1 Viewer)

[Fred Ruhe]

Gerald Mayr, Thomas Lechner and Madelaine Böhme, 2023

Nearly complete leg of an unusual, shelduck-sized anseriform bird from the earliest late Miocene hominid locality Hammerschmiede (Germany)

Historical Biology 35(4): 465–474

Abstract and free pdf: https://www.researchgate.net/public...ocene_hominid_locality_Hammerschmiede_Germany

We describe leg bones of a larger-sized representative of the Anatidae from the Tortonian of the Hammerschmiede clay pit in southwestern Germany. Allgoviachen tortonica, n. gen. et sp. differs from most other representatives of the Anatidae in tarsometatarsus characters. The holotype is among the most substantial records of an anatid from this stratigraphic period in Central Europe and shows unusual morphological features that impede a straightforward phylogenetic assignment. In overall proportions, the tarsometatarsus resembles that of the extant taxon Sarkidiornis and some Tadornini, whereas the hypotarsus morphology differs from all extant Anatidae. Because of its resemblance to the early Miocene taxa Paranyroca and Cygnopterus, the new species may be a stem group representative of the Anatidae, but more osteological data are required for a firm phylogenetic placement. We show that anseriform birds exhibit a previously unnoticed diversity of the ungual phalanges of the pedal digits, and the curved unguals of the fossil indicate a predominantly non-aquatic way of living. The Hammerschmiede avifauna also includes a very small anseriform, which may belong to the extinct taxon Mioquerquedula; equally small species of the Anatidae are today restricted to tropical and subtropical regions,

Enjoy,

Fred

 

[Fred Ruhe]

Systematic palaeontology

Aves Linnaeus, 1758
Anseriformes Wagler, 1831
Anatidae Leach, 1820
Allgoviachen, n. gen.

Type species
Allgoviachen tortonica, n. sp.

Diagnosis
Characterised by tarsometatarsus (1) fairly long and slender, with (2) deep fossa infracotylaris dorsalis, (3) prominent and mediolaterally narrow eminentia intercotylaris; (4) proximal articular face deep with fossa between cotyla medialis and cotyla lateralis; (5) dorsomedial side of shaft with marked furrow for musculus extensor hallucis longus; (6) hypotarsus without canal for tendon of musculus flexor digitorum longus and (7) with plantarly prominent and proximodistally long crista medialis; (8) trochlea metatarsi II short, reaching only to middle of trochlea metatarsi IV; (9) fossa metatarsi I absent; (10) ungual phalanges with well developed and proximally situated tuberculum flexorium.

Differential diagnosis
The new species differs from:

• all extant taxa of the Anatidae in the plantarly more prominent and proximodistally longer crista medialis, the narrower and more pointed eminentia intercotylaris, and the deeper fossa infracotylaris dorsalis.
• the Oligo-Miocene Cygnopterus Lambrecht, 1931 in: tarsometatarsus shaft somewhat stouter in its distal section; cotyla medialis more strongly medially protruding; eminentia intercotylaris more projected; crista medialis hypotarsi less laterally deflected; trochlea metatarsi II proportionally larger; plantar articular surface of trochlea metatarsi IV proportionally longer.
• the early Miocene Paranyroca Miller and Compton, 1939 in: fossa infracotylaris dorsalis deeper; hypotarsus with sulcus for tendon of musculus flexor perforatus digiti 2; crista medialis more prominent.
• the late Miocene Anserobranta (Kurochkin and Ganea 1972) in: tarsometatarsus shaft stouter and trochlea metatarsi II proportionally larger.
• the late Miocene Heteroanser (Zelenkov 2012a) in: eminentia intercotylaris narrower and more pointed; crista medialis hypotarsi proximodistally longer.

Taxonomic remarks
Owing to a lack of overlap in the known bones, the new taxon cannot be differentiated from Bonibernicla (Zelenkov 2012a).

Etymology
From allgovia (Lat.: Allgäu), in reference to the geographic provenance of the fossil, and chen (Gr.: goose).

Allgoviachen tortonica, n. gen. et sp.

Holotype
SNSB-BSPG 2020 XCIV 1058: left leg including the distal portion of the femur as well as the tibiotarsus, tarsometatarsus and most pedal phalanges.

Etymology
The species epithet refers to the stratigraphic age of the new species.

Diagnosis
As for genus.

Referred specimen
GPIT/AV/00143: fragmentary distal portion of left tarsometatarsus (HAM 5).

Type locality and horizon
Hammerschmiede clay pit near Pforzen (Allgäu region, Bavaria, Germany); stratigraphic horizon HAM 4, earliest late Miocene, Tortonian (MN 8, 11.44 Ma).

Measurements
Tibiotarsus, length, 125.8; distal width, 14.1. Tarsometatarsus, length, 74.1; proximal width, 14.7; width of trochlea metatarsi III, ~6.2. Pedal phalanges: I1, 14.1; I2, 6.1; II1, 33.3; II2, 26.5; II3, >11.0; III1, 33.5; III2, >23.4; IV1, 27.1; IV2, 18.7; IV3, >12.7; IV4, 16.7; IV5, >8.4.

Fred


Figure 1. In-situ photo of the partial leg of Allgoviachen tortonica, n. gen. et sp. from the earliest late Miocene (Tortonian) of the Hammerschmiede clay pit (holotype, SNSBBSPG 2020 XCIV 1058). Abbreviations: tbt, tibiotarsus; tmt, tarsometatarsus. The toes are numbered. Photo by Henrik Stöhr.

 

[Fred Ruhe]

I am very sorry, I just found out this species was already discussed by Albertonykus and me last year, so in 2022. not in 2023.
See Allgoviachen tortonica gen. et sp. nov.

Fred

 

[l_raty]

I am very sorry, I just found out this species was already discussed by Albertonykus and me last year, so in 2022. not in 2023.

True but the paper does not include evidence of registration in ZooBank, hence it was not published for the purposes of nomenclature in 2022.
(And it may conceivably not be published yet, actually. It is included in an online issue of the journal on the publisher's website, with final page numbers, but this does not necessarily mean that this issue has been physically distributed.)

 

[Fred Ruhe]

True but the paper does not include evidence of registration in ZooBank, hence it was not published for the purposes of nomenclature in 2022.
(And it may conceivably not be published yet, actually. It is included in an online issue of the journal on the publisher's website, with final page numbers, but this does not necessarily mean that this issue has been physically distributed.)

That is true, this would mean the 2022 paper is not valid and the 2023 paper is.

Fred