GEOLOGICA BALCANICA, 40. 1–3, Sofia, Dec. 2011, p. 13–30. New fossil record of the Late Pliocene kestrel (Falco bakalovi Boev, 1999) from the type locality in Bulgaria Zlatozar Boev National Museum of Natural History, Bulgarian Academy of Sciences, 1, Tsar Osvoboditel Blv., 1000 Sofia, Bulgaria; e-mail: [email protected]; [email protected] (Accepted in revised form: 10.03.2011) Abstract. Twenty six new bone finds of 4 individuals (2 adult and 2 juvenile) have been described and referred to the Late Pliocene kestrel Falco bakalovi Boev, 1999. They came from the species type locality near the town of Varshets (northwest Bulgaria) and demonstrate specific distinguishing from all known falcons of the “tinnunculus” group. They enrich the bone morphology of that falcon covering a large variety of 16 different skeletal elements. Boev, Z. N. 2011. New fossil record of the Late Pliocene kestrel (Falco bakalovi Boev, 1999) from the type locality in Bulgaria. Geologica Balcanica 40(1–3), 13–30. Key words: Falco bakalovi, Falcons, fossil birds, Late Pliocene, Villafranchian Bulgaria. INTRODUCTION The finds come from the type locality near the town of Varshets in northwest Bulgaria and are associated with Until now a total of 11 fossil species were described in F. bakalovi, the only known falcon of the site until now. the genus Falco Linnaeus, 1758. Only two of them were They are the first confirmation of the existing of this spe- considered valid species from Europe (Mlíkovský, 2002). cies and enlarge its morphological characteristics. Until recently, F. medius Umanskaya, 1981 from the Late Miocene (MN 11-13) in south Ukraine was the only known falcon of the Miocene of both Eurasia and Africa and the MATERIAL AND METHOD oldest record of the genus. Recently, F. bul garicus, anoth- er and older Miocene falcon of “tinnunculus” group has Abbreviations: Anatomical: c. – cotyla; cond. – condylus; been described from SW Bulgaria (Late Miocene; Boev, dex. – dextra; dig. – digitus, digiti; dist. – distalis; f. a. – 2011). The second species is the present F. bakalovi Boev, facies a.; max. – maximum; min. – minimum; pr. – proc- 1999. Falco umanskajae Sobolev 2003 (Late Pliocene, essus, processi; prox. – proximalis; sin – sinistra; s. a. – MN 16) from the vicinities of Odessa in Ukraine, is con- sulcus articularis; tbt – tibiotarsus; tmt – tarsometatarsus. sidered “nomen nudum” (Wikipedia, 2011). Outside Institutional: BMNH – Natural History Museum, former- Europe only one Neogene species, F. ore­­gonus Brodkorb, ly British Museum (Natural History), Tring; NMNHS – 1946 (Early/Middle Pliocene of Oregon, USA), has been National Museum of Natural History, Bulgarian Academy described. of Sciences, Sofia; UCBL – University Claude Bernard, The Pliocene falcon F. bakalovi has been designat- Lyon 1, France. ed through a synsacral fragment (holotype) collected in The material was collected through screening and 1990. Since that time additional excavations for collect- washing of the sediments. It consists of 26 bones and ing of fossil material have been undertaken which lasted bone fragments, representing 16 skeletal elements of several years. both fore limbs and the pectoral girdle, and the hind Part of the collected rich material, still unexamined limbs and the pelvis girdle: No NMNHS 122-124; 131- completely, belongs to a small falcon. Boev (1999 a, b; 132, 134-136, 143-145, 181, 189, 223, 294, 304-306, 2002) listed a total of sixteen new finds identified as 317-321, 364, 14 952 and 14964. The finds belong to 2 Falco ex gr. tinnunculus. In addition, some finds col- adult and 2 juvenile individuals from MNI 4. They have lected in the last two years were also referred to this fal- been collected by the author in a 12-year period (1991- con. All this material is the subject of the present paper. 2001) from the type locality near the town of Varshets, 13 NW Bulgaria. The material was identified by comparison and Livezey and Zusi (2006). The chronostratigraphy with the holotype in the reference avian skeleton collec- follows Mein (1990) and Guerin (1990). tion of the NMNHS, as well as the osteological collec- All measurements (Tables 1–16, Fig. 1) have been tions of the Centre des Sciences de la Tèrre, Université taken using calipers to 0.05 mm accuracy, but read to Claude Bernard – Lyon (UCBL) in 1994–1995 and the the 1st digit after decimal point. Description of the meas- Natural History Museum, Tring, a part of the Natural uring manner of some bones in fossil and recent Falco: History Museum, London, former British Museum of humerus dex. dist.: a – thickness of condylus dorsalis; Natural History (BMNH) in 1999 and 2003. It is kept in b – thickness of condylus ventralis; c – total width of c. the Vertebrate Animal Department of the NMNHS. dorsalis and c. ventralis (Table 4); ulna sin. prox.: a – lon- The taxonomy follows White et al. (1994). The osteo- gitudinal diameter of cotyla ventralis; b – transversal di- logical terminology is after Baumel and Witmer (1993) ameter (length) of cotyla dorsalis; c – maximum width of Fig. 1. Manner of measurings of the pelvis in Falconidae (Drawings Vera Hristova) 14 proximal diaphysis; d – length of depressio m. brachialis; Genus Falco Linnaeus, 1758 e – width of diaphysis at the middle of depressio m. bra- Falco bakalovi Boev, 1999 chialis (Table 5); femur sin. dist.: a – width of distal epi- physis; b – diameter of condylus lateralis; c – diameter Holotype: Postacetabular part of the left half of pelvis, of condylus medialis; d – diameter (thickness) in sulcus NMNHS 1642. Collected on July 25th, 1990 by Z. Boev. intercondylaris; e – cranio-caudal thickness of the dia- Paratypes: humerus dex. dist. NMNHS 135; ulna sin. physis above distal epiphysis (Table 10); tibiotarsus dex. prox. NMNHS 131; ulna dex. dist. NMNHS 14 964; fe- dist.: a – width of distal epiphysis; b – diameter of the mur sin. dist. NMNHS 223; tbt dex. dist. NMNHS 136. condylus medialis; c – diameter of the condylus lateralis; Comparison: See Tables 1–16; Fig. 1 and “Description d – thickness in the incissura intercondylaris; e – width and comparison” section. of diaphysis in the proximal end of sulcus supratendineus Measurements of the paratypes: Tables 1–16; Fig. 1. (Table 11). The manner of other measuring is given on Neodiagnosis: A small-sized (between F. tinnunculus and Fig. 1. All generic names of the binominals are given ab- F. subbuteo) fossil species of genus Falco, differing by breviated in the text and are in full in the Appendix 1. the sharp transition (turn) of crista iliaca dorsolateralis “Smaller”, “much smaller”, “larger” or “much larger” over the ala ischii and the rounded (oval), but not angular in the “Comparison and discussion” section mean that shape of the caudal edge of foramen ilioischiadicum. the fossil specimen differs considerably in size from the Distinguishing differences from: (A) the modern F. tin- specimens of the compared species, and thus their taxo- nunculus: (1) distal humerus: blunter (rounder) epicondy- nomic identity is excluded. lus ventralis; (2) рroximal ulna: shallower fossa under c. dorsalis, and almost twice narrower depressio m. brachi- alis; (3) distal ulna: thicker cond. ventralis ulnae in caudal SYSTEMATIC PALAEONTOLOGY view; (4) distal femur: much higher crista tibiofibularis in caudal view; (5) distal tbt: much thicker wall of the medial The general morphology of all 26 finds indicates that tendineal fossa above c. medialis; from (B) the Miocene they belong to the group of the small falcons (Falco F. bul garicus: (1) proximal ulna, (2) distal humerus and sp. ex gr. tinnunculus). As F. bakalovi is the only known (3) distal tibiotarsus much stouter and robust. representative of that group in the Varshets locality, we Locality: A ponor in a rocky hill, 6 km NNE of the town refer all these finds to the same species. of Varshets (43.13° N, 23.17° E). Unconsolidated, un- stratified sediments accumulated as terra-rossa clay. The Order FALCONIFORMES (Sharpe, 1874) fossil bones are broken, locally forming a bone breccia. Family FALCONIDAE (Vigors, 1824) Chronology: Villafranchian. The associated mam mal Subfamily Falconinae (Vigors, 1824) fauna (Spassov 1997 a, b, 2000; Popov, 2001) gave Table 1 The measurements of coracoid sin. in some fossil and recent Falco (ref. to Fig. 1 A) Taxa a b c d e Fossil – Varshets Falco bakalovi NMNHS 304 2.4 2.8 2.1 10.2 4.6 Recent Falco chicquera BMNH 1965.18.1 3.5 3.5 2.0 11.7 ca. 7.1 Falco chicquera BMNH 1993.2.5 2.6 2.8 1.7 10.0 6.1 Falco columbarius BMNH 1930.3.24.264 2.4 2.8 1.9 10.0 5.8 Falco columbarius BMNH 1930.3.24.267 2.7 2.6 1.8 10.5 6.6 Falco columbarius BMNH 1988.61.1 2.7 3.1 1.7 10.6 7.0 Falco naumanni BMNH 1955.15.2 2.6 2.9 1.6 8.9 6.2 Falco naumanni BMNH 1961.13.4 2.2 2.8 1.6 3.8 5.5 Falco newtoni BMNH 1897.5.10.29 2.2 2.6 1.5 7.4 ca. 4.7 Falco sparverius BMNH 1954.3.2 2.0 2.4 1.7 7.2 5.2 Falco subbuteo BMNH 1985.76.1 2.8 3.2 2.3 11.1 7.3 Falco subbuteo BMNH 1994.39.1 3.0 3.3 1.8 11.5 7.3 Falco subbuteo UCBL 111/2 2.9 2.7 1.8 11.4 5.2 Falco tinnunculus BMNH 1930.3.24.275 2.9 3.1 1.8 10.3 6.9 Falco tinnunculus UCBL 119/2 2.6 2.4 1.6 9.2 4.6 Falco tinnunculus UCBL 119/3 2.8 2.6 1.7 9.3 4.6 Falco vespertinus BMNH 1855.4.4.9 2.3 2.9 2.0 9.4 6.0 Falco vespertinus BMNH 1869.10.19.12 2.3 2.4 1.8 8.7 5.2 Falco vespertinus BMNH 1952.3.122 2.5 3.2 1.8 9.7 6.3 15 16 ← Fig.