Athene inexpectata, Pavia & Manegold & Haarhoff, 2015

Pavia, Marco, Manegold, Albrecht & Haarhoff, Pippa, 2015, New early Pliocene owls from Langebaanweg, South Africa, with first evidence of Athene south of the Sahara and a new species of Tyto, Acta Palaeontologica Polonica 60 (4), pp. 815-828 : 820-823

Athene inexpectata sp. nov.

Fig. 2A, C–F, G .

Etymology: From Latin inexpectatus, unexpected, because it is the first African record of Athene South of the Sahara.

Type material: Holotype: right tarsometatarsus, SAM-PQ-L13052 N2, complete . Paratypes: sternum, SAM-PQ-L24592 J, cranial part; right scapula, SAM-PQ-L25390 GA, cranial end; right humerus, SAM-PQ-L33540 C, distal half; right ulna, SAM-PQ-L14846 , distal half; left tibiotarsus, SAM-PQ-L20700 M, almost complete, only lacking proximal end; right tibiotarsus, SAM-PQ-L28927 , proximal end; right tibiotarsus, SAM-PQ-L42828 A, distal end; left tarsometatarsus, SAM-PQ-L20926 , distal half right tarsometatarsus, SAM-PQ-L43568 , complete .

Type horizon: Muishond Fontein Pelletal Phosphorite Member of the Upper Varswater Formation; early Pliocene ( Hendey 1974, 1981; Roberts et al. 2011).

Type locality: Langebaanweg , South Africa .

Referred material. —Left humerus, SAM-PQ-L20691YE, distal end; left humerus, SAM-PQ-L43566, distal end; right humerus, SAM-PQ-L43565, distal end; left ulna, SAM-PQ-L14849, distal end; right femur, SAM-PQ-L33521H, proximal end; left tarsometatarsus, SAM-PQ-L20691H3, distal end; left tarsometatarsus, SAM-PQ-L20701X, distal half; left tarsometatarsus, SAM-PQ-L56223, proximal end; right tarsometatarsus, SAM-PQ-L25293DZ, proximal end; right tarsometatarsus, SAM-PQ-L25293GM, distal end; right tarsometatarsus, SAM-PQ-L28199FN, distal end; right tarsometatarsus, SAM-PQ-L33704A, distal half; right tarsometatarsus, SAM-PQ-L43569, distal half.

Diagnosis. —Species of the genus Athene slightly larger and stouter than At. noctua ( Tables 5–7). Athene inexpectata sp. nov. is distinguished from At. noctua by the scapula having pneumatic foramen on the acromion, a pronounced epicondylus dorsalis on the distal humerus, an elongated tibiotarsus, and a stout tarsometatarsus with wide cotylae. The new species also differs from At. cunicularia by its less elongated tibiotarsus and stouter tarsometatarsus, from At. megalopeza by its stouter tarsometatarsus, and from the various extinct Mediterranean insular species of Athene , such as At. angelis , At. cretensis , At. trinacriae , and At. vallgornerensis by the different proportions of the hind limb bones ( Tables 5–7) and some morphological characters in the various long bones ( Weesie 1982; Mourer-Chauviré et al. 1997; Pavia and Mourer-Chauviré 2002; Guerra et al. 2012).

Description.— Athene inexpectata sp. nov. is described on the basis of 23 more or less complete bones. It can be referred to Athene on the basis of the following morphological characters previously pointed out by Pavia and Mourer-Chauviré (2002): scapula: (i) facies articularis humeralis rounded and mainly mediolaterally oriented, (ii) articular facet on the medial side of the facies articularis humeralis wide, (iii) crista ligamenti acrocoracoacromiali absent; humerus: (iv) fossa musculi brachialis wide and shallow, (v) condylus dorsalis proximally well developed; ulna: (vi) condylus dorsalis ulnaris ventrally well developed and joining the shaft with a square angle; femur: (vii) crista trochanteris weakly developed; tibiotarsus: (viii) proximal part of the crista fibularis separated from the proximal end, (ix) incisura intercotylaris narrow and deep, (x) condylus lateralis wide and expanded laterally in caudal view; tarsometatarsus: (xi) lateral side of the cotyla lateralis rounded in proximal view; (xii) sulcus extensorius exceeding the middle of the shaft; (xiii) tuberositas musculi tibialis cranialis weakly developed; (xiv) medial groove on the trochlea metatarsi III deep; (xv) trochlea metatarsi III protruding more distally than the others.

The area of the foramina pneumatica as well as the labrum internum of the fragmentary sternum of At. inexpectata sp. nov. are both wider than in At. noctua . The facies articularis humeralis of the scapula of the new species is more square than in At. noctua , and the articular facet on the medial side of the facies articularis humeralis is wider. In At. inexpectata sp. nov., there is a pneumatic foramen on the medial side of the acromion that is absent in At. noctua but present in At. cunicularia . The facies articularis clavicularis is more developed in At. inexpectata sp. nov. than in At. noctua . The sulcus scapulotricipitalis and epicondylus dorsalis of the humerus of the new species are more pronounced than in At. noctua . The distal end of the ulna of At. inexpectata sp. nov. is characterized by the tuberculum on the ventral side of the condylus ventralis ulnaris being much more obvious than in At. noctua . The facies articularis acetabularis and the fovea ligamentum capitis of the femur are larger in At. inexpectata sp. nov. than in At. noctua . The linea intermusculi cranialis is more pronounced and more medially situated than in At. noctua and the facies articularis antitrochanterica is caudally less developed.The trochanter femoris is generally more developed and more separated from the impressiones obturatoriae in the new species. Although incompletely preserved, the tibiotarsus of At. inexpectata sp. nov. is much more elongated than that of At. noctua . In fact, the tibiotarsus of At. inexpectata can be estimated to have been as long as 70 mm, whereas the mean for the length of the tibiotarsus in At. noctua is 57.5 mm, the minimal width of the tibiotarsus is similar in both species ( Fig. 2 , Table 6). The proximal tibiotarsus of the new species is characterized by a more distally oriented crista patellaris and a more developed distal part of the crista cranialis lateralis, which also has a deeper sulcus intercnemialis. The crista cnemialis lateralis is more medially oriented than in At. noctua . The sulcus extensorius on the distal end of the tibiotarsus in the new species is more defined, triangular-shaped, and originates further proximal on the shaft. The medial and lateral margins of the sulcus extensorius are thinner than in At. noctua . The tarsometatarsus of At. inexpectata sp. nov. is slightly larger and stouter than that of At. noctua ( Fig. 2 , Table 7). The proximal end of the new species is characterized by the cotyla lateralis being wider and more rounded, and by the

Horizon Specimen

SAM-PQ-L13052N2, SAM-PQ-L14846,

SAM-PQ-L14849, SAM-PQ-L20691H3,

Langeberg Quartz SAM-PQ-L20691YE, SAM-PQ-L20700M, Sand Member SAM-PQ-L20701X, SAM-PQ-L20704EI, (LQSM) SAM-PQ-L20926, SAM-PQ-L25293DZ, SAM-PQ-L25293GM, SAM-PQ-L25390GA, SAM-PQ-L28199FN, SAM-PQ-L56223

SAM-PQ-L24592J, SAM-PQ-L33521H,

Muishond Fontein

SAM-PQ-L33540C, SAM-PQ-L33704A,

Pelletal Phosphorite

SAM-PQ-L43508, SAM-PQ-L43565,

Member (MPPM)

SAM-PQ-L43566, SAM-PQ-L43569

LQSM or MPPM SAM-PQ-L28927, SAM-PQ-L42828A eminentia intercotylaris also being wider and less pointed compared with At. noctua . The cotyla medialis is less rounded but more extended plantarly in At. inexpectata sp. nov. than in At. noctua . The trochleae metatarsi are more robust in the new species. In particular, the trochlea metatarsi II of At. inexpectata sp. nov. shows the area of the fovea ligamenti collateralis to be more developed whilst the plantar side of the same trochlea is thinner than in At. noctua .

Measurements. —Right tarsometatarsus SAM-PQ-L13052N2 (holotype): total length 38.0 mm; distal width 9.1 mm; distal depth 6.4 mm; minimum width of shaft 4.1. For additional measurements, see Tables 5–7.

Stratigraphic and geographical range.—Langeberg Quartz Sand Member and Muishond Fontein Pelletal Phosphorite Member of the Upper Varswater Formation at Langebaanweg, early Pliocene of South Africa ( Table 8).

Figures

Fig. 2. Strigid owl Athene inexpectata sp. nov. from the early Pliocene, Upper Varswater Formation at Langebaanweg, South Africa; paratypes (A, C–E, G), holotype (F) and Athene noctua, Recent (B). A. Left tibiotarsus (SAM-PQ-L20700 M), in cranial (A 1), lateral (A 2), caudal (A 3), medial (A 4), and distal (A5) views. B. Reversed right tibiotarsus (MGPT-MPOC 38), in cranial view (B 1), left tarsometatarsus in dorsal view (B 2). C. Left scapula (SAM-PQ-L25390 GA), in medial (C 1), cranial (C 2) and lateral (C 3) views. D. Right ulna (SAM-PQ-L14846), in dorsal (D 1), caudal (D 2), ventral (D 3) and cranial (D 4) views. E. Right tibiotarsus (SAM-PQ-L28927), in cranial (E 1), lateral (E 2), caudal (E 3), medial (E 4), and proximal (E5) views. F. Right tarsometatarsus (SAM-PQ-L13052 N2), in dorsal (F 1), lateral (F 2), plantar (F 3), medial (F 4), proximal (F5), and distal (F6) views. G. Right humerus (SAM- PQ-L33540 C), in cranial (G 1), dorsal (G 2) caudal (G 3), ventral (G 4), and distal (G5) views.