Bulletin of the Natural History Museum - Plovdiv Bull. Nat. Hist. Mus. Plovdiv, 2020, vol. 5: 25-31

A Little Dabbling Duck (Anatini Vigors, 1825 - Anseriformes Wagler, 1831) from the Late Miocene of Kremikovtsi (Bulgaria)

Zlatozar N. Boev*

National Museum of Natural History, Bulgarian Academy of Sciences, 1 Blvd. Tsar Osvoboditel, 1000 Sofia, BULGARIA *Corresponding author: [email protected]; [email protected]

Abstract. A late Miocene (Turolian) small anatine is reported by a proximal half of right carpometacarpus from the late Miocene (MN 12-13) locality near Kremikovtsi (Sofia City Province). Dimensionally it is closer and similar to modern Spatula querquedula, but shows significant morphological differences. It is the second oldest record of the small dabbling ducks in Europe and the first record on the Balkan Peninsula.

Key words: Neogene birds, Miocene avifauna, ducks, Turolian, Kremikovtsi locality, Sofia Miocene Basin.

Introduction Measurements (in mm; Table 1), see Figure 2. Waterfowl are very rare in the pre- Total length of the fragment – 29.2; width of Pleistocene avian record in Bulgaria (Boev, trochlea carpalis - > 4.0; dorsoventral thickness 2002). So far three species and a genus have of proximal epiphysis with processus pisiformis been described from the Bulgarian late Miocene – 4.7; craniocaudal width in the middle of the and early Pliocene localities: Miocene: Anser diaphysis of os metacarpale majus – 2.9; thraceiensis Burchak-Abramovich & Nikolov, dorsoventral thickness in the middle of os 1982 and Anatinae gen. et sp. indet. from metacarpale majus - 3.0. Other measurements Troyanovo; Pliocene: Balcanas pliocaenica are given on Table 1. Boev, 1998 from Dorkovo (BOEV, 2002) and The taxonomy follows MLÍKOVSKÝ (2002) Cygnus verae Boev, 2000 from Sofia - 2. and DICKINSON & REMSEN (2013). The The locality of Kremikovtsi is one of total of osteological terminology is after BAUMEL & the nine Neogene avian sites in Bulgaria. Besides WITMER (1993). those three listed above, the remaining sites are: Abbreviations: Anatomical: dex. - dextra; Sofia-1, Muselievo, Hadzhidimovo, Kalimantsi, prox. - proximalis; Institutional: ISEAK – Gorna Sushitsa, Hrabarsko, Troyanovo, Azmaka Institute of Systematics and Evolution of Animals (Polish Academy of Sciences), and Kardam. Some of them were listed by BOEV (2002). The described specimen is the only Krakow; NMNHS - National Museum of waterfowl and avian at all find from this Miocene Natural History (Bulgarian Academy of locality. Sciences), Sofia.

Material and Methods Description of the site The examined find represents an The site is located near the Kremikovtsi village incomplete right proximal half of (Sofia Region), 42046’36”; 23032’27”; UTM grid GN carpometacarpus bone – NMNHS 2948 (Fig. 03; 18.65 km NE of Sofia City. It represents 1). The proximal epiphysis and two thirds of os lacustrine deposits revealed in an open limestone metacarpale majus are preserved.

© Bull. Nat. Hist. Mus. Plovdiv Regional Natural History Museum – Plovdiv http://rnhm.org/en/ University of Plovdiv Publishing House A Little Dabbling Duck (Anatini Vigors, 1825 - Anseriformes Wagler, 1831) from the Late Miocene... quarry at ca. 700 m a. s. l. The material was collected 1766) and D. autumnalis (Linnaeus, 1758) in 1995 by Prof. NIKOLAY SPASSOV (NMNHS). were compared) because of larger size (Table 1) and the sharper edge of the dorsal condyle of Results trochlea carpalis. Recently SUN et al. (2017) Associated fauna and age of the even proposed to consider whistling ducks as Kremikovtsi locality separate family Dendrocygnidae (Reichenbach, So far data on other groups are extremely 1850). Dendrocygini can also be excluded scarce. Only separate finds of “Mammut” because of marked notch of the dorsal trochlear rim (WORTHY 2009). borsoni Hays, 1834 (MARKOV, 2005) and Giraffidae Gray, 1821 gen. indet. were collected. After its associated macromammalian Oxyurinae fauna the site is dated late Miocene (MN 12-13) Differences from Oxyurinae (Oxyura (N. SPASSOV, inpubl. data). jamaicensis (Gmelin, 1789)): lacking of sharply angled groove “F” (Fig. 3) on the midline of the Description of the find trochlea carpalis, smaller fovea carpalis caudalis The examined specimen NMNHS 2948 (“D”; Fig. 3), and more distally positioned represents an incomplete proximal right inception of the proximal epiphysis of symphysis. carpometacarpus. It is rather worn, especially to the Other genera of Oxyurinae (Stictonetta L. rims of the trochlea carpalis and processus Reichenbach, 1853, Malacorhynchos Swainson, extensorius is broken off. It has a distinct notch on 1831) are endemics to Australia and New Zealand, the dorsal rim of the carpal trochlea, which refers while the Neogene (Early Miocene) Mionetta the find to Anatinae and distinguishes it from Livezey & Martin, 1988 is referred to Dendrocygninae (WOOLFENDEN, 1961; WORTHY, Dendrocheninae Livezey & Martin, 1988. 2009). Fovea carpalis caudalis (cuneiform fossa) is Because of all presented features the specimen very deep, another feature specific for Anatini (and NMNHS 2948 could not be referred to the tribes Cairini) after WOOLFENDEN (1961). On the other Mergini, Tadornini and Aythyini, and the side, the minor metacarpal is convex and lacks a subfamilies Oxyurinae and Anserinae. Tadornini groove, which is an important feature that is not (partly), Aythyini and Anserinae were not seen in most anatines (TREVOR WORTHY, pers. compared as their species have considerable comm.). morphometric differences. Tribes Malacorhynchini The specimen is stored at the collections of and Cereopseini belong to Anserinae (DICKINSON the Vertebrate Animals Department of the & REMSEN, 2013), despite that WORTHY & LEE National Museum of Natural History, Sofia, (2008) and WORTHY (2009) proved that Bulgarian Academy of Sciences. Earlier the find Malacorhynchini should be placed in Oxyurinae. was published as “Anatinae gen.” without any descriptions (BOEV, 2002). Mergini It differs from Mergus by the almost Systematic part perpendicular, instead sharp-angled, axis of Order: Anseriformes Wagler, 1831 trochlea carpalis towards longitudinal axis of Family: Anatidae Leach, 1820 diaphysis, although heavily eroded dorsal Subfamily Anatinae Leach, 1820 trochleal rim (Fig. 1). Tribe Anatini Vigors, 1825 Tadornini Comparison with recent small anatids Differences from Tadornini (Tadorna tadorna After DICKINSON & REMSEN (2013) (Linnaeus, 1758)): much smaller size and bigger Anatidae is split into 4 subfamilies – asymmetry of the caudal part of trochlea carpalis in Dendrocygninae, Oxyurinae, Anserinae, and caudal view, as well as the more longitudinal Anatinae. Anatinae is divided into 4 tribes – orientation of the ventral edge of os metacarpale Mergini, Tadornini, Aythyini, and Anatini. minus towards longitudinal axis.

Dendrocygninae Aythyini Dendrocygninae Reichenbach, 1850 is The Kremikovtsi specimen differs from excluded (Dendrocygna viduata (Linnaeus, Aythyni (Aythya marila (Linnaeus, 1761))

26 Zlatozar N. Boev chiefly by the smaller dimensions and relatively end. Spatula, Anas and other Anatinae have a slender os metacarpalis majus. distinct groove (Fig 3). After TREVOR WORTHY (pers. comm.) there is a groove in some but not Anatini all oxyurines. Notable is the more medially positioned The three species of the former tribe processus pisiformis on the ventral surface of Tachyerini (now regarded as Anatinae; DICKINSON the bone. The preserved features on the & REMSEN, 2013) also were not compared because fragment allow it to refer it to a small-sized of their endemic distribution in the southern anatids in the metric range of Spatula regions of South America (HOWARD & MOORE, querquedula (Linnaeus, 1758) – Mareca 1980) and their much larger sizes. penelope (Linnaeus, 1758) (Table 1). General The specimen NMNHS 2948 could not be shape of the preserved proximal fragment of referred to Anas notwithstanding the wide size carpometacarpus, straight os metacarpalis range of the numerous species of that genus. It major, the proximal symphysis and the profile differs from Anas by the almost perpendicular, of the metacarpal trochlea are similar to these instead sharp-angled, axis of trochlea carpalis elements in the small anatines. It also differs towards longitudinal axis of diaphysis, although from Aix galericulata (Linnaeus, 1758) the heavily eroded dorsal trochleal rim (Fig. 1). same way, as well as by the presence of clearly WOELFE (1967) states that in the recent West- outlined fovea “В” (Fig. 2). From Aix sponsa Palearctic small anatids (e.g. A. crecca) the (Linnaeus, 1758) it differs by the lesser individual metric variability of the bone asymmetry of trochlea carpalis and deeper and measurements is considerable. better outlined fovea “В” (Fig. 2), as well as smaller size. Comparison with fossil small anatids On the other hand, the specimen differs MLIKOVSKÝ (2002) lists a total of 8 fossil from S. querquedula by the thicker diaphysis of anatids described from Cenozoic (mainly os metacarpale majus, the constriction “А” of Neogene) localities in Europe: Mionetta os metacarpale minus (Fig. 3), and the blanchardi (Milne-Edwards, 1863), M. natator elongated (kidney-like), rather than rounded, (Milne-Edwards, 1867), M. robusta (Milne- shape of the fovea “В” (Fig. 2) on the ventral Edwards, 1868), Anas velox Milne-Edwards, surface. The specimen differs from Anas crecca Linnaeus, 1758 by the deeper fovea “B” and 1868, A. sansaniensis Milne-Edwards, 1868, fossa infratrochlearis (“C”; Fig. 2) and by the Aythya chauvirae Cheneval, 1987, Mergus lacking of the bend “А” (Fig. 3), besides its connectens Janossy, 1972, and Oxyura doksana dimensional similarity. Anas strepera (Linnaeus, Mlikovsky, 2002. A. velox and A. sansaniensis 1758) is much bigger and the trochlea carpalis are known from the middle Miocene (MN 6). is less concave in caudal view. Similarly, as well After MLIKOVSKÝ (2002) the allocation of both as the smaller dimensions, NMNHS 2948 species to the genus Anas is uncertain. differs from M. penelope and Mareca falcata Mionetta Livezey & Martin, 1988 and Oxyura (Georgi, 1775). Metrically it stands closer to Bonaparte, 1828 are oxyurines and could be Sibirionetta formosa (Georgi, 1775) and neglected (see above), Sharganetta mongolica resembles it by the shape of fovea carpalis Zelenkov, 2011 and Protomelanitta gracilis caudalis (“D”), but it differs by the constriction Zelenkov, 2011 described from the middle “А” (Fig. 3) and the thicker diaphysis Miocene of Mongolia are defined as medium sized (measurements “c” and “d”; Fig. 2). The ducks, and so are much larger than this fossil, and examined specimen differs from Spatula discors so can be excluded from our comparison. (Linnaeus, 1766) by the feature “А” (Fig. 3), Nogusunna conflictoides Zelenkov, 2011 from the well-developed fovea “В” (Fig. 3) and more same region and age, is more interesting, as it is elongated, rather than rounded shape of the determined as “small duck, slightly larger than the fossa infratrochlearis (“С”; Fig. 2). The extant smew Mergellus albellus” (ZELENKOV, specimen differs also by the convex caudal 2011; р. 196), but could not be compared as only surface of os metacarpalis minus at its proximal humeri are available of that species.

27 A Little Dabbling Duck (Anatini Vigors, 1825 - Anseriformes Wagler, 1831) from the Late Miocene...

Fig. 1. Anatini gen. indet. NMNHS 2948 – carpometacarpus dex. prox.: dorso-cranial view (a), dorso-caudal view (b), vental view (c). Photographs: Z. Boev.

Table 1. Comparison of the measurements (mm) of the proximal carpometacarpus of fossil and recent small anatids. Measurements are defined in Fig. 2.

Species a b c d e Fossil - Kremikovtsi Anatini gen. indet. NMNHS 2948 ca.11.2 ca.4.1 3.9 3.0 2.9 Recent Spatula querquedula NMNHS 1/2000 11.5 3.9 3.0 2.7 2.5 Spatula querquedula NMNHS 15/2003 12.3 4.5 3.5 3.2 2.4 Spatula querquedula ISEAK A-3119/762 10.0 4.1 3.8 3.0 2.4 Spatula querquedula ISEAK A-272/62 8.6 3.8 2.9 2.7 2.1 Spatula discors ISEAK A-3 823/81 9.7 3.9 2.8 3.0 2.1 Anas strepera NMNHS 1/1994 8.8 5.2 4.4 4.1 2.9 Anas crecca NMNHS 4/1994 9.9 3.7 3.1 2.8 1.9 Anas crecca ISEAK A-1924/68 9.6 3.9 4.1 3.0 2.1 Mareca penelope ISEAK A-5298/94 11.7 5.2 3.7 3.9 3.0 Mareca falcata ISEAK A-3261/76 12.7 5.2 3.7 3.9 3.0 Sibirionetta formosa ISEAK A-5092/92 10.4 4.1 3.4 2.9 2.2 Aix galericulata NMNHS 1/1989 11.4 4.8 3.4 3.3 2.0 Aix galericulata ISEAK A-5303/94 11.5 5.1 3.3 3.6 2.6 Aix sponsa NMNHS 1/1993 13.6 5.0 3.8 3.3 2.3 Oxyura jamaicensis ISEAK A-4657/89 9.6 3.9 2.6 2.8 1.9 Dendrocygna viduata NMNHS 1/2004 16.5 4.9 3.4 3.3 2.7 Dendrocygna viduata NMNHS 2/2004 15.2 5.0 3.1 2.9 2.6 Dendrocygna autumnalis NMNHS 1/2004 16.9 6.2 4.5 4.0 3.6 Mergellus albellus ISEAK A-3440/77 11.3 4.6 3.1 3.4 2.2 Tadorna tadorna ISEAK A-3975/83 17.3 6.5 ca.4.7 ca.5.0 3.5

28 Zlatozar N. Boev

Fig. 2. Measurements (mm) a-e used in Table 1 for the proximal carpometacarpus of small anatids. B - fovea, C - fossa infratrochlearis. Other features are shown on Fig. 3 and described in the comparisons section. Drawing: Vera Htistova.

Fig. 3. Comparison of right proximal carpometacarpus (caudal view), left to right: Tadornini (T. tadorna), Anatini (S. querquedula), Anatini gen. indet. NMNHS 2948, Mergini (Mergulus albellus (Linnaeus, 1758)), Aythyni (A. marila), Cairinini (Aix galericulata), Oxyurinae (O. leucocephala). Features B and C are shown on Fig. 2. Drawing: Z. Boev.

29 A Little Dabbling Duck (Anatini Vigors, 1825 - Anseriformes Wagler, 1831) from the Late Miocene... Mioquerquedula minutissima Zelenkov & approaches to Spatula querquedula (Table 1), Kurochkin, 2012 and Aix praeclara Zelenkov but the large notch A (Fig. 2) and the lacking of & Kurochkin, 2012 are described from the a groove on os metacarpalis minor clearly middle Miocene of Mongolia. Again the distinguish it from that species. Unfortunately comparison is impossible due to the lacking of the fragmentary nature of the find does not homologous skeletal elements. As allow further taxonomic determination. So, we “Mioquerquedula is smaller in size than all identify it as Anatini gen. indet. Anseriformes, except for Nettapus” As ZELENKOV (2003) summarized, in the (ZELENKOV & KUROCHKIN, 2012; 425), it late Miocene, a number of dabbling (surface- could be excluded from our comparison. feeding) ducks (genus Anas), were widespread Anas soporata Kurochkin, 1976 from the in Europe and Asia. He defines the late middle Pliocene of Mongolia is one of the Miocene as “third” stage of the evolution of smallest dabbling ducks (KUROCHKIN, 1976). ducks, which is “…characterized by the Anas molesta Kurochkin, 1985 from the dominance of ducks of the genera Anas s. l. middle Pliocene of Mongolia “… is slightly and Aythya… The third stage probably began bigger than S. querquedula, A. formosa and in Turolian,…” (p. 36). Our Turolian specimen similar to A. clypeata.” (KUROCHKIN, 1985; p. of Kremikovtsi, identified as Anatini gen. 47). S. clypeata is significantly bigger than S. indet., only marks the occurrence of the small dabbling ducks in the present Sofia Valley in querquedula, the closest species to specimen the Turolian. As well known, the existence of a NMNHS 2948 in terms of dimensions. late Miocene large freshwater basin (s. c. Sofia The early Pliocene Balcanas pliocaenica “Pontian” lacustrine-palustrine basin), is firmly from Dorkovo (CS Bulgaria) dimensionally fits proved by other numerous geological and to the compared specimen of Kremikovtsi, but paleozoological evidences (KOJUMDZIEVA, the lacking of homologous skeleton elements 1989; ANGELOVA & YANEVA, 1998). doesn’t allow further conclusions. On the other hand, the Kremikovtsi duck is the In addition in the “Incertae sedis” section earliest dabbling duck of Anatinae in the Balkan MLIKOVSKÝ (2002) lists seven species of g. Anas: region (MLÍKOVSKÝ, 1996, 2002), although some Anas albae Janossy, 1979, Anas eppelsheimensis waterfowl groups are known from the late Miocene Lambrecht, 1933, Anas isarensis Lambrecht, 1933, on the Balkans ((black geese, Branta thessaliensis Anser brumeli Milne-Edwards, 1871, Anas Boev & Koufos, 2006 from Greece) or the early oeningensis Meyer, 1865, Anas risgoviensis Pliocene (dubbling ducks, B. pliocaenica from Ammon, 1918, and Anser scaldii Beneden, 1872. Bulgaria). Thus, the duck of Kremikovtsi is the Unfortunately, all of them (except A. albae), are second oldest Miocene record of the small dabbling incomparable, as the present location of described ducks in Europe and the earliest record on the specimens is unknown, they were destroyed in the Balkan Peninsula. World War II, considered “Nomen nudum”, “cannot be identified within the family Anatidae”, Acknowledgments “no evidence that the species belonged to the genus The author is very grateful to Prof. ZYGMUNT Anas”, “taxonomic position is in need of restudy”, BOCHEŃSKI (1935-2009) and Prof. TERESA TOMEK etc. (MLIKOVSKÝ (2002; p. 124-125). Diagnosis of (ISEAK) for their valuable help during the work at A. albae (Late Miocene (MN 13) of Polgardi, their institute. He also thanks to Dr. TREVOR Hungary): “A very small duck with a smaller and WORTHY (School of Biological Sciences, Flinders slenderer carpometacarpus than that of the hitherto University, Adelaide, Australia) and Dr. GERALD known Eurasian fossil or recent ducks.” (JANOSSY, MAYR (Forschungsinstitut Senckenberg, Frankfurt 1979, p. 16). The total length of A. albae is 33.7 am Main, Germany) for their very helpful reviews of mm, while in the Kremikovtsi specimen it is ca. 60 the previous version of the manuscript. mm (as the studied fragment is long ca. 29 mm). References Discussion ANGELOVA D., YANEVA M. 1998. New Thus, we could only assume that the lithostratigraphical data about the Neogene compared specimen refers to Anatini tribe. of Sofia Basin. Review of the Bulgarian Dimensionally and in general morphology it Geological Society, 59(2): 37-40.

30 Zlatozar N. Boev BAUMEL J. J., WITMER L. M. 1993. Osteologia. In: National Museum of Natural Historry, Baumel J., King A., Breazile J., Evans H., BAS. Synopsis of Ph. D. thesis. Sofia, Vanden Berge J. (Eds.), Handbook of 32 p. (In Bulgarian, English summary). avian anatomy: Nomina Anatomica MLÍKOVSKÝ J. 1996. Tertiary avian localities Avium. Pub. Nutall Orn. Cl. 23. of Europe. Univerzita Karlova, Praha Cambridge, Massachusetts, pp. 45-132. 1995, 39 (1995): pp. 517-853. BOEV Z. 2002. Neogene avifauna of Bulgaria. MLÍKOVSKÝ J. 2002. Cenozoic Birds of the In: Zhou Z., Zhang F. (Eds.), World. Part 1: Europe. Praha: Ninox Proceedings of the 5th Symposium of Press, 406 p. the Society of Avian Palaeontology and SUN Z., PAN T., HU C., SUN L., DING H., Evolution, Beijing, 01-04.06.2000. WANG H., ZHANG C., JIN H., CHANG Science Press, Beijing, pp. 29-40. Q., KAN X., ZHANG B. 2017. Rapid and DICKINSON E.C., REMSEN JR. J.V. (Eds.) 2013. recent diversification patterns in The Howard & Moore Complete Anseriformes birds: Inferred from Checklist of the Birds of the World. 4th molecular phylogeny and diversification Edition, Vol. 1, Aves Press, Eastboume, analyses. PLoS ONE 12(9): e0184529. U.K., 461 p. WOELFE E. 1967. Vergleichend morphologische HOWARD R., MOORE A. 1980. A complete Untersuchungen an Einzelknochen des cheiklist of the birds of the World. postcranialen Skelettes und Sorger. Oxford Univ. Press, Oxford, 701 p. Inaugural. Dissertation Institute für JANOSSY D. 1979. Plio-Pleistocene bird remains Paläontologie, Domesticationsforshungs from the Carpathian basin. IV. und Geschichte der Tiermedizin der Anseriformes, Gruiformes, Charadriiformes, Universitat Munchen, 231 p. Passeriformes. Aquila, 85: 11-39. WOOLFENDEN G.E. 1961. Postcranial KOJUMDZIEVA E. 1989. 2.Е.1. Continental osteology of the waterfowl. Florida State Pontian sediments in Southern Mus. Bull. (Biol. Sci.) 6: l-l 29. Bulgaria. Chronostratigraphie und WORTHY T., LEE M. 2008. Affinities of Miocene Neostratotypen. Neogen der Westlichen waterfowl (Anatidae: Manuherikia, (“Zentrale”) Paratethys. Bd. VIII. Dunstanetta and Miotadorna) from the St Pontien. Aufgenommen in den Bathans fauna, New Zealand. Naturwissenschaftlichen Klassen am Palaeontology 51 (3): 677–708. 25.06.1988. in SANU am 4.10.1988. In: WORTHY T. 2009 Descriptions and Jugoslawische Akademie der phylogenetic relationships of two new Wissenschaften und Künste Serbische genera and four new species of Oligo- Akademie der Wissenschaften und Miocene waterfowl (Aves: Anatidae) Künste. Zagreb - Beograd, pp. 357-359. from Australia. Zoological Journal of KUROCHKIN E. 1976. New data on Pliocene birds the Linnean Society, 156: 411-454. of Western Mongolia. In: Kramarenko N. ZELENKOV N. 2011. Diving Ducks from the N. (Ed.), Paleontology and biostratigraphy Middle Miocene of Western Mongolia. of Mongolia. Trudi Sovmestnoy Sovetsko- Paleontological Journal 45 (2): 191-199. Mongolskoy paleontologicheskoy ekspeditsii ZELENKOV N. 2013. Miocene evolution of 3: 51-67. (In Russian). Eurasian ducks. Casarca 16: 13-36. KUROCHKIN E. 1985. Birds of the Central Asia ZELENKOV N. ,KUROCHKIN E. 2012. in Pliocene. The joint Soviet-Mongolian Dabbling Ducks (Aves: Anatidae) from Paleontological Expedition. Transactions, the Middle Miocene of Mongolia. 26, 120 p. Paleontological Journal 46 (4): 421-429. LIVEZEY B. 1986. A phylogenetic analysis of recent anseriform genera using morphological characters. The Auk 103: 737-754. MARKOV G. 2005. Fossil proboscideans Accepted: 27.09.2020 (Proboscidea, Mammalia) of Bulgaria. Published: 20.12.2020

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