[Papers in Palaeontology, Vol. 4, Part 3, 2018, pp. 309–326]

THE MIDDLE MIOCENE DUCK CHENOANAS (AVES, ANATIDAE): NEW SPECIES, PHYLOGENY AND GEOGRAPHICAL RANGE by NIKITA V. ZELENKOV1 , THOMAS A. STIDHAM2,NICOLAYV. MARTYNOVICH3,NATALIAV.VOLKOVA1,QIANGLI2 and ZHUDING QIU2 1Borissiak Paleontological Institute of Russian Academy of Sciences, Profsoyuznaya 123, 117647 Moscow, Russia; [email protected] 2Key Laboratory of Vertebrate Evolution & Human Origins of the Chinese Academy of Sciences, Institute of Vertebrate Paleontology and Paleoanthropology, Chinese Academy of Sciences, Beijing 100044, China 3The Museum of the World Ocean, 236006 Kaliningrad Russia

Typescript received 13 September 2017; accepted in revised form 6 December 2017

Abstract: A notable reorganization of the waterfowl westward dispersal or range expansion of this group of communities apparently took place across Eurasia during ducks during the Miocene, comparable to the previously the middle to early late Miocene, when primitive and established biogeographical affinities of many Eurasian extinct anatid taxa (e.g. Mionetta) were replaced by more mammals. These data also support a growing body of evi- derived forms, including extant genera. However, little is dence that avian faunas of Siberia were similar to Euro- known about the diversity of Eurasian waterfowl and their pean ones during the Middle Miocene Climatic Optimum. palaeobiogeography during this critical interval. In particu- Our data indicate a wide Eurasian distribution (more than lar, larger ducks of the middle Miocene are represented by 8000 km) and a greater diversity within the genus Chenoa- poorly known taxa including ‘Anas’ sansaniensis from nas during the late early to middle Miocene. The phyloge- western and central Europe and Chenoanas deserti from netic analysis of Chenoanas suggests that it may be a Western Mongolia. We report new geographically wide- primitive member of Anatini, and thus does not belong to spread specimens referred to Chenoanas from Mongolia, the basal radiation of extinct relatives of stiff-tailed ducks eastern Siberia, and China that include a new species, (Oxyura and its relatives). Species of Chenoanas were Chenoanas asiatica sp. nov., and allow for recognition of probably not specialized divers. the European ‘Anas’ sansaniensis as a member of Chenoa- nas. We describe the oldest remains of Chenoanas Key words: middle Miocene, Anatidae, Eurasia, osteology, sansaniensis from eastern Siberia, which supports a palaeobiogeography.

M ODERN-TYPE ducks first appear in the fossil record in taxa (for example, Mionetta) were replaced by more the late Oligocene (23.0–28.1 Ma) when they already derived ones, including forms that exhibit close affinities occupied a very wide, probably global, geographical distri- to modern genera (e.g. Aix praeclara, Zelenkov & Kur- bution (Mourer-Chauvire et al. 2004; Worthy 2009) with ochkin 2012; see also reviews in Zelenkov 2012, 2016a). the stem of Anatidae known to extend into the late This turnover event is coincident with the timing of the Eocene (Mayr 2008, 2017; Stidham & Ni 2014). The sub- major genus-level differentiation within Anatinae, as sequent early Miocene (16–23 Ma) waterfowl faunas do inferred from molecular studies (Fulton et al. 2012; not differ significantly from the late Oligocene ones Mitchell et al. 2014). The study of middle Miocene water- (Hugueney et al. 2003; Mourer-Chauvire 2008), and fowl faunas is thus particularly important for understand- primitive relatives of Oxyura (see Worthy & Lee 2008) ing the evolutionary origin of modern waterfowl apparently dominated many waterfowl communities at biodiversity. that time (Worthy & Lee 2008; Worthy 2009). A signifi- Despite these indications of a waterfowl radiation cant reorganization of the taxonomic composition of (and turnover), the middle Miocene waterfowl commu- waterfowl communities, at least in Eurasia, apparently nities of Eurasia (and North America) remain poorly took place during the middle Miocene or early late Mio- studied. Early authors (Milne-Edwards 1867–1871; Lam- cene (7.3–16.0 Ma). During this time interval, primitive brecht 1933) used a limited number of modern taxa for

© The Palaeontological Association doi: 10.1002/spp2.1107 309 310 PAPERS IN PALAEONTOLOGY, VOLUME 4 comparisons, and thus provisionally placed several mid- MATERIAL AND METHOD dle Miocene ducks within modern genera (mostly Anas). These identifications are partly explained by the We follow the taxonomy of modern ducks presented by absence of elaborated views on the systematics and phy- Dickinson & Remsen (2013) and the osteological logenetic diversity of ducks at that time. Only recently, nomenclature in the Nomina Anatomica Avium (Baumel several fossil species and new genus-level taxa were et al. 1993) with several exceptions for widely-used com- introduced for middle Miocene ducks from Mongolia mon English terms (e.g. ‘shaft’ and ‘capital shaft ridge’). (Zelenkov 2011, 2012; Zelenkov & Kurochkin 2012) and We further use the term ‘tuberculum brachiale’ instead North America (Stidham & Hilton 2016; Stidham & of ‘facies articularis clavicularis,’ which is not present in Zelenkov 2017). However, almost nothing is known ducks (see Zelenkov & Panteleyev 2015). For compar- about their geographical and temporal distributions, due isons, the following modern taxa of birds have been to a scarcity of reported avian localities and specimens examined (number of specimens, when different from from that time interval. Here we show that a primitive one, is given in parentheses): Anas acuta (13); A. ba- duck genus Chenoanas, originally described for a single hamensis; A. crecca (19); A. laysanensis; A. platyrhynchos species from the middle Miocene of Mongolia, had a (41); A. poecilorhyncha (2); A. undulata (2); Aix galericu- much wider geographical distribution (and greater lata (3); A. sponsa (4); Alopochen aegyptiaca (2); Aythya diversity) across both Europe and Asia during the mid- affinis (2); A. americana; A. baeri; A. collaris; A. ferina dle Miocene (Fig. 1). The type species, Chenoanas (2); A. fuligula (6); A. marila (2); A. nyroca (3); A. val- deserti, was established on the basis of two bone frag- isineria (2); Biziura lobata; Bucephala clangula (2); B. al- ments from Western Mongolia (Zelenkov 2012), but beola; Cairina moschata; Callonetta leucophrys; new fossils from Mongolia, China and eastern Siberia Chenonetta jubata (2); Chloephaga melanoptera (2); Ch. (Lake Baikal) represent additional material of the type picta; Clangula hyemalis; Dendrocygna bicolor; D. javan- species and a new species described below. Additionally, ica; D. arborea; Histrionicus histrionicus (2); Lophonetta we refer several fossil specimens of ducks from contem- specularioides; Malacorhynchus membranaceus; Mareca poraneous localities in France to the genus Chenoanas. penelope (20); M. americana; M. sibilatrix (2); M. falcata These records add to our understanding of the mor- (5); M. strepera (12); Marmaronetta angustirostris; Mela- phology of this taxon, allow for its phylogenetic analysis nitta perspicillata; M. fusca (2); M. nigra; M. americana; for the first time, and demonstrate that at least some Mergellus albellus (3); Mergus serrator (2); M. squamatus; waterfowl taxa had a very wide Eurasian distribution M. merganser (2); Netta rufina (4); N. peposaca; Nettapus during or close to the Middle Miocene Climatic Opti- auritus (2); N. coromandelianus; Nomonyx dominicus; mum (MMCO), similar to that of many modern species Oxyura jamaicensis; Plectropterus gambensis; Polysticta of duck. stelleri (3); Pteronetta hartlaubii; Sibirionetta formosa (2);

FIG. 1. General map of localities with remains of Chenoanas spp. 1, Sansan (France; middle Miocene, MN 6), C. sansaniensis;2, Atzelsdorf (Austria; early late Miocene, basal part of MN 9), C. cf. sansaniensis; 3, Tagay (eastern Siberia, Russia; late early Miocene, MN 5), C. sansaniensis; 4, Sharga (Mongolia; middle Miocene, MN 7+8), C. deserta, C. asiatica; 5, Tairum Nor/locality 346 (Inner Mongolia, China; middle Miocene, MN 7+8), C. asiatica. Scale on the map varies considerably across latitude due to the Mercator projection; the minimum distance between Sansan (1) and Tairum Nor (5) is about 8150 km. ZELENKOV ET AL.: MIOCENE DUCK CHENOANAS 311

Somateria mollisima (2); S. spectabilis (3); S. fischeri; SYSTEMATIC PALAEONTOLOGY Spatula versicolor; S. hottentota (2); S. querquedula (12); S. discors (2); S. cyanoptera; S. rhynchotis (2); S. clypeata by Nikita V. Zelenkov and Thomas A. Stidham (14); Stictonetta naevosa; Tachyeres pteneres; T. patachoni- cus; Tadorna ferruginea; T. cana; T. variegata; T. tadorna (2); T. tadornoides (3); and Thalassornis leuconotus (2). Class Aves Linnaeus, 1758 The majority of these skeletons are from the E.N. Kur- Order Anseriformes Wagler, 1831 ochkin osteological collection (EK; stored at Borissiak Family Anatidae Leach, 1820 Paleontological Institute of Russian Academy of Sciences, Genus Chenoanas Zelenkov, 2012 PIN), but specimens from the following institutions were also examined: Museum national d’Histoire naturelle, 1891 Anas Linnaeus; Lydekker, p. 114 (pars). Paris (MNHN); National Museum of Natural History, 1912 Anas Linnaeus; Paris, p. 290 (pars). Washington DC (USNM); and Bernardino Rivadavia 1933 Anas Linnaeus; Lambrecht, S. 356 (pars). Natural Sciences Museum (Buenos Aires). Fossil repre- 1964 Anas Linnaeus; Brodkorb, p. 220 (pars). sentatives of Anatidae stored at: Bayerische Staatssamm- 1987 Anas Linnaeus; Cheneval, p. 142 (pars). lung fur€ Pal€aontologie und Geologie (Munich); MNHN; 2000 Anas Linnaeus; Cheneval, p. 329 (pars). Museum fur€ Naturkunde Berlin; Naturhistorisches 2002 Anas Linnaeus; Mlıkovsky, p. 118 (pars). Museum Wien; USNM; PIN; Staatliches Museum fur€ 2012 Chenoanas Zelenkov, p. 520. Naturkunde Stuttgart (SMNS); and the Institute of Ver- 2013 Chenoanas Zelenkov; Zelenkov & Martynovich, tebrate Paleontology and Paleoanthropology, Chinese p. 79. Academy of Sciences in Beijing (IVPP) were also exam- 2015 Chenoanas Zelenkov; Zelenkov & Kurochkin, ined. The codings for newly-added outgroup taxa Mega- p. 174. podius reinwardt and Lithornis promiscuus were prepared generally using Houde (1988) and Worthy et al. (2017), Type species. Chenoanas deserta Zelenkov, 2012, middle but comparative skeletal collection of PIN and fossil Miocene of Western Mongolia. material stored in USNM were also consulted. Mammal Neogene (MN zonation) terminology is used Included species. Chenoanas sansaniensis (Milne-Edwards, to describe the biostratigraphic ages of specimens. 1867), late early to middle Miocene of eastern Siberia and France; C. deserta Zelenkov, 2012, middle Miocene of Phylogenetic analysis. To assess the phylogenetic position Western Mongolia; C. asiatica Zelenkov & Stidham sp. of Chenoanas, we analysed the matrix from Worthy nov., middle Miocene of Inner Mongolia (China) and (2009; an extended version of the matrix from Worthy Western Mongolia. & Lee 2008) using the heuristic search in TNT 1.5 (Goloboff & Catalano 2016). We added additional Diagnosis (emended after Zelenkov 2012). Humerus:in primitive taxa Lithornis promiscuus and Megapodius caudal view, caput humeri dorsoventrally at least twice reinwardt (see Worthy et al. 2017; Appendix) in order wider than proximodistally high; in cranial view, incisura to better polarize character states. Lithornis promiscuus capitis forming distinct, relatively shallow incisure in the was used as the outgroup. We used the following proximal margin of the bone; tuberculum dorsale subtrian- options: 5000 replicates of Wagner trees, TBR branch- gular in outline, its proximal part raised and positioned at swapping algorithm, 10 trees retained at each step. All the level of the caput humeri, and the distal part is almost characters were treated as equally weighted, 35 charac- flush with caudal bone surface or only slightly elevated ters were treated as ordered (see Worthy 2009). We above it; the capital shaft ridge is moderately developed used the topological constraint as described in Worthy and is not sharp; it is directed towards the ventral half of & Lee (2008), but also tested the matrix in un- tuberculum dorsale; the fossa pneumotricipitalis ventralis constrained analyses. The original matrix includes 150 is deep and well pneumatized, its opening facing distocau- morphological characters coded for 67 taxa. To test dally (tuberculum ventrale is proximocaudally oriented). the influence of the fossil record on the inferred Coracoid: In cranial view, the transverse (mediolateral) axis topology, we also ran analyses excluding various fossil of the processus acrocoracoideus (the plane through the taxa. We performed an additional analysis with the depth of the process) forms acute angle with the plane of inclusion of Chenoanas and two new extant taxa (Mar- the shaft (acrocoracoid poorly inclined ventrally); the sul- maronetta and Pteronetta) (see Appendix for character cus m. supracoracoidei is excavated markedly and not scorings). pneumatized; the tuberculum brachiale overhangs the sul- 312 PAPERS IN PALAEONTOLOGY, VOLUME 4 cus m. supracoracoidei throughout its whole depth; the least one other genus-level anatid taxon, and thus Che- medial margin of the shaft almost does not incline medially noanas can be best diagnosed by the unique combination toward the omal end; the processus acrocoracoideus pro- of features provided above. A comprehensive set of com- trudes beyond the medial margin of the shaft; and the parisons of the Chenoanas humerus was provided with facies articularis humeralis is dorsoventrally wide (its the original description (Zelenkov 2012) and will not be dorsoventral depth roughly equals its craniocaudal length). repeated here. However, it should be noted that from the Tibiotarsus: the longitudinal axis of the condylus lateralis is original diagnosis of the genus (Zelenkov 2012) we have proximodistally aligned and distally does not incline medi- excluded several less meaningful characters of the ally; the condyli are proximodistally short in cranial view humerus, including one character related to the structure (shorter than the width of the incisura intercondylaris); in of the crista deltopectoralis, which was found to be vari- distal view, the incisura intercondylaris is shallow and wide able in the new material referred to this genus (see (slightly wider than the condylus lateralis); and the condyli below). A characteristic feature of the humerus of Che- subequally protrude cranially. noanas is the proximocaudally aligned (i.e. proximally directed; character 57 in Worthy & Lee 2008) tuberculum Comparisons. Like the majority of extant and fossil genera ventrale of the humerus (Fig. 2), which itself results in a of ducks, the genus Chenoanas lacks definitive autapo- mostly caudal (rather than caudodistal) orientation of the morphic features (at least based on currently known opening of the fossa pneumotricipitalis. This humeral skeletal elements, which do not include any portion of morphology is most likely to be a primitive condition the skull). All of the character states of the humerus, because it also is present in dendrocygnines and anser- coracoid and tibiotarsus of Chenoanas are present in at ines. Among Anatinae, this primitive condition is retained

FIG. 2. Proximal humeri of Chenoanas spp. compared with selected extant taxa. A, C. sansaniensis, MNHN Sa10226, locality Sansan, France, middle Miocene (MN6); B, G, I, C. deserta, holotype PIN 4869/196, locality Sharga, Mongolia, middle Miocene (MN7+8). C, H, J, C. asiatica, holotype PIN 4869/68, locality Sharga, Mongolia, middle Miocene (MN7+8). D, Tadorna variegata, specimen EK 39- 11-1, modern. E, Anas platyrhynchos, specimen EK 1141-1, modern. F, C. asiatica, IVPP 23894, locality Tairum Nor, Inner Mongolia, China, middle Miocene (MN7+8). A–F, caudal views; G–H, ventral views; I–J, angled (disto-dorsocaudal) views. Abbreviations: ch, caput humeri; cdt, caudally oriented tuberculum ventrale; crt, proximo-cranially oriented tuberculum ventrale; csr, not sharp caudal shaft ridge oriented towards the ventral part of tuberculum dorsale; dp, deep pneumatic pocket inside the fossa pneumotricipitalis; fpd, fossa pneumotricipitalis dorsalis, fpv, fossa pneumotricipitalis ventralis; ic, incisura capitis; iic, incisure in the proximal margin of the bone formed by incisura capitis; ild, linea m. latissimi dorsi; sc, scar located distal to crus dorsale fossae; st, sulcus transversus; td, tuberculum dorsale; ttd, triangular tuberculum dorsale with elevated proximal part and lowered distal part; tv, tuberculum ventrale. Scale bars represent 1 cm. Colour online. ZELENKOV ET AL.: MIOCENE DUCK CHENOANAS 313 in Chenonetta and Tadorna (but not other Tadornini), Mergellus (among the Merginae), and also in Callonetta but not Callonetta, where the coracoid is superficially (Fig. 3L). Representatives of the genera Aix, Nettapus and similar to that of Chenoanas (see below). Such morphol- Malacorhynchus have a somewhat intermediate condition ogy is also present in Pinpanetta fromensis (but is not of this character, but they still differ from Chenoanas in present in the other species of that genus) and Australota- the outline of the extremitas omalis. Chenoanas may be dorna from the Oligocene of Australia (Worthy 2009). It easily distinguished from members of Mergini by the pres- is notable that in Chenoanas this clearly primitive feature ence of a tuberculum brachiale that overhangs the deeply is present along with several derived humeral characters, excavated sulcus m. supracoracoidei. Among the exam- including the presence of the notch in the proximal mar- ined ducks, Callonetta leucophrys has the most similar gin of the bone formed by the incisura capitis, and a outline of the omal end of the coracoid (Fig. 3), but can rather elongate and partly lowered tuberculum dorsale. still be distinguished from Chenoanas by an extensively Another primitive Eurasian Miocene duck group, Mio- pneumatized sulcus m. supracoracoidei under the tuber- netta, is characterized by an alternative combination of culum brachiale. The facies articularis humeralis is nota- character states, with no incisure in the proximal margin bly more craniocaudally elongated and dorsoventrally of the bone, an elevated tuberculum dorsale, and a cau- narrower in Callonetta than in Chenoanas. dally directed tuberculum ventrale. Although the distal end of the tibiotarsus is usually The presumably flightless Bambolinetta is rather similar rather uniformly similar among anatids, in Chenoanas to Chenoanas in the structure of its proximal humerus this element displays a morphology that is distinct from (see Mayr & Pavia 2014), but it has a large and distinctly that of all living members of the family. As in the major- elevated tuberculum dorsale, and the dorsocaudal surface ity of ducks, the distal end of the tibiotarsus in Chenoa- of the crista deltopectoralis is distinctly concave (unlike nas (Fig. 4) is mediolaterally widened due to a medial that in Chenoanas). In the species of Chenoanas, the displacement of the condylus medialis, but unlike mod- tuberculum dorsale is weakly to moderately elevated, and ern Anas and several other groups, the lateral margin of the dorsocaudal surface of the crista deltopectoralis is flat the condylus lateralis is positioned approximately in line to slightly concave. However, we note that the proximal with the adjacent portion of the lateral margin of the humerus in Bambolinetta is poorly preserved, and it actu- shaft (i.e. the condyle is not shifted or inclined medially). ally may be more similar to that of Chenoanas than previ- A similar morphology of the condylus lateralis is present ously stated (Mayr & Pavia 2014). Most importantly, the in modern Dendrocygninae, Anserinae (but not Mala- humerus of Bambolinetta is claimed to be shortened corhynchus), Tadornini, Thalassornis and Chenonetta. This (Mayr & Pavia 2014), but the humerus of Chenoanas feature allows us to differentiate the tibiotarsus of Che- shows no apparent modifications related to flightlessness. noanas from that of other medium-sized fossil ducks, We also added characters of the coracoid as an ele- including many diving taxa, which are common in the ment, which is now known for all three species (see middle Miocene of Eurasia (e.g. Zelenkov 2012; Stidham below) of the genus Chenoanas. A derived feature of the & Zelenkov 2017). In the fossil taxon Mionetta, the coracoid in Chenoanas is that the plane through the condylus lateralis is slightly inclined medially. Chenoanas depth of the processus acrocoracoideus forms an acute differs from all above mentioned taxa except Anserinae angle (about 45°) with the plane of the sternal articula- and Tadornini by proximodistally shortened condyles in tion (character 45 in Worthy & Lee 2008), whereas primi- cranial view (the height of the condyles are less than the tively in Anatidae, these planes are subperpendicular to width of the incisura intercondylaris). Chenoanas differs each other. This character allows for the distinction of from the Anserinae by its notably smaller size, absence of Chenoanas from more primitive taxa such as Dendro- a developed epicondylus medialis, a narrow condylus cygninae, Thalassornis and Anserinae, as well as from div- medialis, and a shallow incisura intercondylaris in distal ing ducks (Aythyini and most Mergini). Tadornines are view. Chenoanas differs from Tadornini by exhibiting a not uniform in this feature. Chloephaga and Alopochen shallow incisura intercondylaris in distal view. Addition- retain the primitive condition, while Tadorna approaches ally, in the extant species of Tadorna, the condylus later- the state in Chenoanas and most Anatinae. The most dis- alis protrudes cranially to a greater degree than the tinctive feature of the coracoid in Chenoanas is that the condylus medialis, but in Chenoanas, both condyles pro- shaft is straight and does not incline medially (and its trude cranially approximately to the same degree. To medial margin in particular) towards the omal end conclude, the morphology of the distal tibiotarsus in (Fig. 3). In most Anatidae (including Anas s.l.), the shaft Chenoanas is more primitive than in most Anatinae, and gradually widens cranially; this feature may or may not it is notable that the distal tibiotarsus resembles that of be correlated with the medial protrusion of the processus Chenonetta and Tadornini; a similar pattern of apparent acrocoracoideus relative to the shaft. A straight shaft, sim- similarity characterizes the proximal humerus of this ilar to that of Chenoanas, occurs in Lophodytes and taxon (Zelenkov 2012). 314 PAPERS IN PALAEONTOLOGY, VOLUME 4

FIG. 3. Coracoids of Chenoanas spp. compared with selected extant taxa. A–C, C. deserta, PIN 4869/57, locality Sharga, Mongolia, mid- dle Miocene (MN7+8). D–F, C. asiatica PIN 4869/18, locality Sharga, Mongolia, middle Miocene (MN7+8). G–H, C. asiatica IVPP, 23895, locality Tairum Nor, Inner Mongolia, China, middle Miocene (MN7+8). I–K, C. sansaniensis PIN 2614/176, locality Tagay, eastern Siberia, Russia; late early Miocene (MN5). L–N, Callonetta leucophrys, EK 40-9-1, modern. O–Q, Anas acuta, EK 40-40-2, modern. Upper row, ventral view; middle row, medial view; bottom row, dorsal view. Abbreviations: ess, excavated and non-pneumatized sulcus m. supra- coracoidei; cs, cotyla scapularis; fah, facies articularis humeralis; ila, impressio lig. acrocoracohumeralis; lg, labrum glenoidale; msm, medi- ally inclined medial margin of the shaft; npa, almost not protruding processus acrocoracoideus relative to the medial margin of the shaft; pa, processus acrocoracoideus; pp, processus procoracoideus; ppa, processus acrocoracoideus protruding medially relative to the medial margin of the shaft; sms, sulcus m. supracoracoidei; ssm, straight (not medially inclined) medial margin of the shaft; tb, tuberculum bra- chiale overhanging sulcus m. supracoracoidei throughout its whole depth. Scale bar represents 1 cm. Colour online.

Chenoanas asiatica sp. nov. Derivation of name. The species name refers to the Asiatic Figures 2C, F, H, J; 3D–F distribution of the species.

LSID. urn:lsid:zoobank.org:act:BE619470-4421-4709-94E6- Holotype. PIN 4869/68, proximal fragment of right 0EC3DCC2D3FD humerus. ZELENKOV ET AL.: MIOCENE DUCK CHENOANAS 315

FIG. 4. Various skeletal elements of Chenoanas spp. and selected extant taxa. A–B, Chenoanas sansaniensis, lectotype MNHN SA1223, distal tibiotarsus, locality Sansan, France, middle Miocene (MN6). C–D, Tadorna variegata, EK 39-11-1, distal tibiotarsus, modern. E– F, Chenonetta jubata, specimen EK 40-12-1, distal tibiotarsus, modern. G–H, Anas platyrhynchos, specimen EK 40-30-3, modern. I, C. sansaniensis, PIN 2614/186, fragmentary pelvis, locality Tagay, eastern Siberia, Russia; late early Miocene (MN5). J–K, C. sansanien- sis, MNHN SA1223, proximal carpometacarpus, locality Sansan, France, middle Miocene (MN6). L–M, C. deserta, PIN 4869/9, left sca- pula, locality Sharga, Mongolia, middle Miocene (MN7+8). N–O, Chenoanas sp., specimen PIN 4869/164, cranial sternum, locality Sharga, Mongolia, middle Miocene (MN7+8). Abbreviations: cl, condylus lateralis tibiotarsi; cm, condylus medialis tibiotarsi; iic, inci- sura intercondylaris tibiotarsi; pcl, poorly cranially protruding condylus lateralis (subequal to condylus medialis); scl, straight (not medially inclined) condylus lateralis; si, spina interna sterni; wii, wide incisura intercondylaris (wider than either condyle). Scale bars represent 1 cm. Colour online.

Type locality and age. Sharga, middle Miocene, Western Referred material. Sharga locality, Mongolia: PIN 4869/ Mongolia. Collected by the Joint Soviet–Mongolian Pal- 18, cranial end of right coracoid; PIN 4869/50, 51, cranial eontological Expedition in 1984. ends of left coracoids. Tairum Nor locality, Inner Mongolia, China: IVPP Diagnosis. Slightly smaller than C. sansaniensis, and V23894, proximal end of a right humerus; and IVPP roughly the size of modern Anas acuta. The new species 23895, a humeral glenoid region of a left coracoid. differs from both C. deserta and C. sansaniensis in having Tairum Nor (also known as Locality 346) is in the Tung- a lowered and more elongate tuberculum dorsale; a linea gur Formation southwest of the city of Erlian (Erenhot) m. latissimi dorsi positioned close to tuberculum dorsale; in central Inner Mongolia, China (Fig. 1; Wang et al. and a caput humeri that is dorsoventrally narrower in 2003). The mammalian fauna from Tairum Nor is very proximal and ventral views. Pneumaticity within the fossa similar to Moergen Fauna (pro. Moergen II in Qiu 1996). pneumotricipitalis ventrale does not extend ventrally, and These two faunas (Moergen and Locality 346) are placed is almost not visible in caudal view in the new species. between the Tairum Nor Fauna (early middle Miocene) Chenoanas asiatica further differs from the similarly-sized and the Tamuqin Fauna (late middle Miocene) of the C. deserta in having a well-developed deep pneumatic Neogene faunal sequence of central Inner Mongolia (Qiu pocket inside the fossa pneumotricipitalis ventrale just et al. 2013). We estimate their age to be in middle or late under the tuberculum ventrale (this pocket extends proxi- middle Miocene within the Tunggurian Chinese Land mocaudally into the tubercle), an almost flat dorsal sur- Mammal Age and equivalent to European MN7+8 (Qiu face of the crista deltopectoralis, and a prominent et al. 2013). Thus, the referred Chinese specimens are longitudinal scar just distal to crus dorsale fossa. Addi- close to, but slightly older than 12 Ma in age (up to tionally, the crus dorsale fossa in C. asiatica is oriented ~12.5 Ma) given the correlation of the upper part of the more distally, and hence the caudal outline of the fossa Moergen Fauna with magnetochron C5A (Wang et al. pneumotricipitalis is more concave, than the state in 2003; Hilgen et al. 2012; Qiu et al. 2013). C. deserti. In ventral view, the crus ventrale fossa is more perpendicular to the long axis of the bone in C. asiatica Description. The holotype is a proximal right humerus broken than it is in C. deserta. near the distal end of the crista deltopectoralis, and it is light 316 PAPERS IN PALAEONTOLOGY, VOLUME 4 brownish in colour (Fig. 2C, H, J). The caput humeri has a dorsally. The tuberculum brachiale has two distinct lobes (dorsal rather straight distal margin and indistinctly overhangs the fossa and ventral) and is indistinctly overhanging the sulcus m. supra- pneumotricipitalis dorsalis. The dorsal aspect of the crista del- coracoidei (Worthy & Lee 2008 character 46 state 0), which is topectoralis is nearly flat dorsally (Worthy & Lee 2008: character poorly exacavated in its most cranial part. Caudally, a distinct 54, state 1). There is a capital shaft ridge, but it is rather broad concavity is present in the dorsal half of the sulcus. The coracoid and rounded (Worthy & Lee 2008: character 51, state 0). The from the Tairum Nor locality (specimen IVPP V23895; Fig. 3G, capital shaft ridge is directed towards the base of the tuberculum H) is poorly preserved but generally agrees with the Mongolian dorsale (Worthy & Lee 2008: character 52, state 2). The dorsal specimens in size and preserved details. tubercle is proximodistally elongate and essentially at the same level as the humeral shaft (Worthy & Lee 2008: character 56, Comparisons. The coracoids are assigned to C. asiatica state 1). Its distal tip is slightly elevated above the surrounding because they have a dorsoventrally narrower (particularly area of the bone. The m. latissimus dorsi posterioris scar is cranially) and more gracile facies articularis humeralis, about 4 mm in length and is positioned 2 mm distal to the corresponding to the narrower and more gracile caput tuberculum dorsale and about the same distance dorsal to the capital shaft ridge. The fossa pneumotricipitalis dorsalis is shal- humerus in this species, as compared to C. deserta. They low and dorsoventrally narrower than the fossa pneumotricipi- further differ from C. deserta in that the dorsal margin of talis ventralis (Worthy & Lee 2008: character 53, state 1). The the facies articularis humeralis slopes cranially (thus add- ventral edge of the fossa pneumotricipitalis dorsalis is distinctly ing to the narrowness of cranial part of the facies), and in marked by the crus dorsale of the fossa pneumotricipitalis ven- that the cotyla scapularis faces mostly dorsally. The sulcus tralis that extends as a ridge (Fig. 2, sc) to the distal broken edge m. supracoracoidei is poorly excavated cranially in C. asi- of the specimens. The tuberculum ventrale is proximoventrally atica, and thus the tuberculum brachiale is nearly does oriented and not significantly overhanging the fossa pneu- not overhang the fossa. The coracoid of C. asiatica differs motricipitalis ventralis, which thus faces not only distally but from that of C. sansaniensis by its smaller size, and in also ventrally. The fossa pneumotricipitalis ventralis is highly exhibiting a notably less concave sulcus m. supracora- pneumatized internally (Worthy & Lee 2008: character 58, state coidei. The facies articularis humeralis is more oval in 0). The dorsoventral width of the fossa pneumotricipitalis ven- tralis is distinctly less than the length of the crista bicipitalis dis- C. asiatica due to the fact that the ventral apex is shifted tal to the tuberculum ventrale (Worthy & Lee 2008: character somewhat caudally. 60, state 0). There is a deep and well-formed pocket positioned Two proximal humeri can be assigned to C. asiatica: just under the tuberculum ventrale (inside the ventral pneu- one from the Sharga locality in Mongolia, and another motricipital fossa). The bicipital crest is partly damaged, but from the Tairum Nor locality in Inner Mongolia there is an elongate concavity extending from the distal end of (China). Both specimens are metrically similar to that the crus ventrale fossae. The capital incisure forms a distinct of C. deserta, but they differ from C. deserta in a num- notch in the proximal margin of the humerus in cranial or cau- ber of features (see Diagnosis). In combination with the dal view (Worthy & Lee 2008: character 59, state 2). On the cra- presence of two morphologically distinct coracoids in nial surface of the bone, the intumiscentia humeri is not the Sharga locality, we strongly favour the presence of significantly protruding, and the sulcus transversus is dorsoven- two similarly-sized anatid taxa. One of the most promi- trally short. nent (derived) characters of the proximal humerus of The right proximal humerus (specimen IVPP V23894; Fig. 2F) from the Tairum Nor locality in Inner Mongolia C. asiatica is the well-developed deep pneumatic pocket (China) agrees with the holotype in the preserved features. It inside the fossa pneumotricipitalis just under the tuber- has a better preserved crista deltopectoralis and adjacent por- culum ventrale. Among living members of Anatidae, tions of the shaft. There is no evidence of the scar of m. latis- this feature occurs in Mareca ducks (particularly pro- simus dorsi anterioris on the specimen except for a slight nounced in M. falcata and M. penelope),butitisalso indentation at the distal edge of the specimen (where the scar present in Chenonetta and (variably) in Aix. This occur- would begin in taxa with a more distally positioned scar). That rence in Chenoanas is the first record of this feature in means that the scar did not extend proximal to the distal end of an extinct anatid, and it is probably an autapomorphy the crista deltopectoralis, and it also did not form a junction of the species. with the distal tip of the crista deltopectoralis (Worthy & Lee 2008: character 62, state probably 1). Remarks. Previously, Zelenkov (2012) described the three In the coracoids from the Sharga locality (specimens PIN partial coracoids from Sharga (here included in C. asiat- 4869/18, 50, 51; Fig. 3D–F), the shaft is nearly straight at the ica) as Anatidae gen. indet., but he noted that they prob- level of the facies articularis humeralis, and thus the processus acrocoracoideus as a whole is not significantly shifted medially. ably represented yet another species of moderate-sized The impressio lig. acrocoracohumeralis gradually widens towards duck (distinct from C. deserta). The new humerus con- its slightly ventrally bent cranial tip. The facies articularis firms the presence of this new species in Sharga. The humeralis notably narrows cranially. The apex of the labrum gle- coracoid specimen from Tairum Nor locality is very noidale is caudally located. The cotyla scapularis faces mostly fragmentary and is slightly smaller than specimens ZELENKOV ET AL.: MIOCENE DUCK CHENOANAS 317 from Sharga, and hence is referred to this species elevated; dorsocaudal surface of the crista deltopectoralis tentatively. slightly concave; and linea m. latissimi dorsi positioned far from tuberculum dorsale. Additionally, the crus dor- Occurrence. Late middle Miocene (MN 7+8) of Sharga sale fossae in C. deserta is oriented more proximally, and (Western Mongolia) and Tairum Nor (Inner Mongolia, hence the caudal outline of the opening of the fossa China). pneumotricipitalis ventralis is less concave, than in C. asi- atica. In ventral view, the crus ventrale fossa is notably more obliquely oriented than in C. asiatica. Pneumaticity Chenoanas deserta Zelenkov, 2012 within the fossa pneumotricipitalis ventralis extends ven- Figures 2B, G, I; 3A–C; 4L–M trally and is easily visible in caudal view.

2012 Chenoanas deserta Zelenkov, p. 522, fig. 1. Type locality and age. Sharga locality; middle Miocene 2012 Anatidae gen. indet.; Zelenkov, p. 523 (pars). (Mammal Neogene Zone MN7+8), western Mongolia 2015 Chenoanas deserta Zelenkov; Zelenkov & Kuroch- (Fig. 1). kin, p. 174, fig. 58. Referred material. Sharga locality: PIN 4869/57, cranial Holotype. PIN 4869/196, proximal fragment of right fragment of right coracoid; and PIN 4869/238, cranial humerus. fragment of left coracoid.

Diagnosis (emended). Relatively large duck, the size of Measurements. See Table 1 and also Zelenkov (2012). modern Anas acuta and Chenoanas asiatica sp. nov., but Note that Zelenkov (2012) provided a maximum width of slightly smaller than C. sansaniensis. Differs from the proximal humerus, and here we present the dorsoven- C. sansaniensis in the following characters of the tral (transverse) width, which differs slightly. humerus: caput humeri proximodistally narrower in cau- dal view; distal margin of the caput humeri only slightly Description and comparisons. See detailed description and com- sigmoidal; and linea m. latissimi dorsi positioned far from parisons of the humerus in Zelenkov (2012). At least two partial – tuberculum dorsale (more distal than the distal end of coracoids (Fig. 3A C) from the type locality Sharga can be referred to this species, because they have a dorsoventrally wider the crista dorsalis fossae). Differs from C. asiatica in: facies articularis humeralis, which apparently corresponds with caput humeri is dorsoventrally wide in proximal view; the wider and more robust caput humerus of C. deserta, as com- lacks well-developed deep pneumatic pocket inside the pared to C. asiatica. Additionally in these coracoids, the dorsal fossa pneumotricipitalis just under the tuberculum ven- margin of the facies articularis humeralis is oriented subparallel trale (wide pneumatized concavity is present in this posi- to the longitudinal axis of the bone (visible in lateral view) tion in C. asiatica); tuberculum dorsale shortened and and the cotyla scapularis faces distinctly dorsolaterally. The

TABLE 1. Measurements of various bones attributed to Chenoanas spp. Taxon Specimen (Locality) Maximal dorsoventral width of facies Length from cranial tip of facies articularis humeralis (mm) articularis humeralis to caudal margin of Coracoid cotyla scapularis (mm)

C. sansaniensis PIN 2614/176 (Tagay) 6.4 10.1 C. deserta PIN 4869/57 (Sharga) 5.8 9.3 C. deserta PIN 4869/238 (Sharga) 5.7 9.2 C. asiatica PIN 4869/51 (Sharga) 5.6 9.2 C. asiatica PIN 4869/18 (Sharga) 5.5 9.3 C. cf. asiatica IVPP V23895 (Tairum Nor) 5.2 9.4

Humerus Dorsoventral width of proximal end (mm)

C. sansaniensis MNHN Sa 10226 (Sansan) ~21 C. deserta PIN 4869/196 18.0 C. asiatica PIN 4869/68 (Sharga) 18.0 C. asiatica IVPP V23894 (Tairum Nor) 17.8 318 PAPERS IN PALAEONTOLOGY, VOLUME 4 tuberculum brachiale in the coracoids of C. deserta overhangs Paralectotype. MNHN SA 1223, distal end of right the sulcus m. supracoracoidei more than in C. asiatica, and does humerus. so across the entire dorsoventral length of the sulcus. The latter character is however subject to some individual variation in modern ducks (NVZ and TAS pers. obs.) and should thus be Type locality and age. Sansan (Gers, France; middle Mio- used with caution in separation of the two species. However, the cene, MN 6). morphology of this area is stable in all of the specimens from Sharga. The coracoid of C. deserta differs from C. sansaniensis in Emended differential diagnosis. Slightly larger than Che- its smaller size and in having a slightly less excavated ventral noanas deserta and C. asiatica, the size of modern non- portion of the sulcus m. supracoracoidei and the presence of an urban specimens of Anas platyrhynchos. The distal margin oval (not triangular) sulcus m. supracoracoidei. of the caput humeri in caudal view is distinctly more sig- The proximal humerus of C. deserta (Fig. 2B, G, I) previously moidal than in C. deserti and in particular C. asiatica. was compared (Zelenkov 2012) with those of other extinct, as Additionally, it differs from C. asiatica in the following well as modern duck genera, because other species of the genus characters of the humerus: tuberculum dorsale elevated Chenoanas were not known. In size and proportions, the humerus is identical to that of C. asiatica sp. nov. (see above), and shorter; linea m. latissimi dorsi moderately offset but differs in a number of osteological details indicated in the from tuberculum dorsale; and the caput humeri is diagnosis. Although some of those characters (e.g. the position dorsoventrally wide in proximal view. Except for size, of linea m. latissimi dorsi) may show some intraspecific and C. sansaniensis differs from C. deserta in having a hum- individual variation in living ducks, a combination of these traits eral head in caudal view that is generally stouter, strongly favours at least a species-level distinction between dorsoventrally shorted, and proximodistally wider in its C. deserta and C. asiatica, further supported by the morphology ventral half. of the coracoid. Referred material. Sansan (France): MNHN SA 1407, Occurrence. This species is currently known only from fragmentary shaft of left coracoid; MNHN SA 1319, the middle Miocene locality Sharga in Eastern Mongolia. 10277, 14012, cranial fragments of scapulae; MNHN SA 10226, proximal fragment of right humerus; MNHN SA 1249, 14010, distal fragments of left humeri; MNHN SA Chenoanas sansaniensis (Milne-Edwards, 1867) 10669, proximal fragment of left radius; MNHN SAN Figures 2A, 3I–K, 4A–B, I–K 636, proximal fragment of left carpometacarpus; and MNHN SA 1401, proximal fragment of right car- 1867 Anas sansaniensis Milne-Edwards, p. 153, pl. 25 figs pometacarpus. 26–30, pl. 26 figs 19–22. Tagay (eastern Siberia, Russia, MN 5): PIN 2614/176, 1891 Anas sansaniensis Milne-Edwards; Lydekker 1891, p. omal end of left coracoid; and PIN 4869/186, fragmentary 116. left ischium. The age of the Tagay locality has been 1912 Anas sansaniensis Milne-Edwards; Paris 1912, p. debated until recently, but a wealth of new biochronolog- 290. ical data on mammals and amphibians correlate the fauna 1933 Anas sansaniensis Milne-Edwards; Lambrecht, S. of Tagay with the Shangwanian faunas of China and sup- 358. port the late early Miocene age of this locality (Erbajeva 1964 Anas sansaniensis Milne-Edwards; Brodkorb, p. 222. & Alexeeva 2013; Tesakov & Lopatin 2015; Klementiev & 1964 Anas sansaniensis Milne-Edwards; Howard, p. 295. Sizov 2015; Syromyatnikova 2016). 1987 Anas sansaniensis Milne-Edwards; Cheneval, p. 144, pl. 1 figs 5–6. 1998 Dendrocygna sansaniensis (Milne-Edwards); Measurements. See Table 1. Further measurements are Mlıkovsky, p. 57. given in Cheneval (1987). 2000 Anas sansaniensis Milne-Edwards; Cheneval, p. 331. 2002 Anas sansaniensis Milne-Edwards; Mlıkovsky, p. Comparisons. Previously, the coracoid of C. sansaniensis 118. was known from a partial specimen from Sansan (MNHN 2013 Chenoanas aff. deserta Zelenkov; Zelenkov & Mar- SA 1407) that preserves only the shaft and cotyla scapu- tynovich, p. 79. laris. The newly referred omal end of a coracoid from 2015 Chenoanas sansaniensis (Milne-Edwards); Zelenkov Tagay (PIN 2614/176) agrees with the specimen from & Kurochkin, p. 174. Sansan in size (width of cotyla scapularis ~4.5 mm) and morphology of the preserved portion. Furthermore, the Lectotype. MNHN SA 1223, distal end of left tibiotarsus Tagay specimen (Fig. 3I–K) is structurally very similar to (selected by Cheneval 1987, p. 145; figured by Milne- the coracoid of C. deserta from Mongolia, and differs Edwards 1868, pl. 25 figs 26–30; Cheneval 1987, pl. 1 fig. 5). from that species only in its larger size and in having a ZELENKOV ET AL.: MIOCENE DUCK CHENOANAS 319 more deeply excavated cranioventral portion of the sulcus mostly uniform morphology of the distal humerus m. supracoracoidei just beneath the tuberculum brachiale. among modern Anatidae does not allow for the recogni- Additionally, the facies articularis humeralis in the speci- tion of other unambiguous characters to distinguish men from Tagay is roughly triangular in outline, and it is C. sansaniensis from extant species of Anas and other more oval in both C. deserta and C. asiatica. Thus, the taxa. larger size (approximately the same as modern Anas The proximal fragment of a right carpometacarpus platyrhynchos) and morphological similarity to C. deserta (MNHN SA 1401) and a fragmentary proximal phalanx strongly support assignment of the specimen PIN 2614/ of the major wing digit (MNHN SA 14011) agree in size 176 to C. sansaniensis. with the corresponding bones of the modern One scapula from Sansan (MNHN SA 14012) roughly A. platyrhynchos and display no significant morphological corresponds in size to that of Anas platyrhynchos and differences from that species. apparently belongs to C. sansaniensis. The scapula has a notably prominent tuberculum coracoideum, as in all Remarks. Mlıkovsky (1988) transferred C. sansaniensis to examined Tadorninae, and in contrast to Anas which has Dendrocygna, but later (Mlıkovsky 2002) followed Chene- a much less prominent tubercle. val (1987) and returned it to Anas, though noting that The proximal humerus of C. sansaniensis from the exact systematic position of this species was unclear. type locality Sansan (Fig. 2A) is close in overall mor- Zelenkov & Martynovich (2013) mentioned a coracoid phology to that of C. deserta, but it is slightly larger and from the Tagay locality in Siberia as belonging to a spe- has a stouter caput humeri (see below). As in C. deserta, cies close to C. deserta. The specimen was not illustrated the tuberculum dorsale is elevated and rather short or described previously, and here we show that it indeed (although it seems to be longer in C. sansaniensis than belongs to C. sansaniensis. An incomplete ischium from in C. deserta), a prominent longitudinal ridge just distal this Siberian locality belongs to a similarly-sized duck, to the distal end of the crus dorsale of the fossa pneu- and thus is here tentatively referred to this taxon. motricipitalis ventralis is not developed, although there The emended diagnosis provided by Cheneval (1987) is a scar in this position. The states of a number of includes only one humeral character: the angle of the characters are not clear given the poor preservation of humeral head reaches the level of the tuberculum ventrale the only known proximal humerus of C. sansaniensis (‘internal tuberosity’). This character is indeed character- from the type locality. In that specimen, the pneumatic- istic for the genus Chenoanas and modern Tadorninae, ity within the fossa pneumotricipitalis ventralis seems to but it is related not to the shape of the humeral head but extend moderately ventrally, intermediate between the rather to the position of the tuberculum ventrale and the condition in C. deserta and C. asiatica. Similarly, the crus dorsale fossae (see above). This character does not position of the linea m. latissimi dorsi is intermediate allow for species level identification within the genus, and between conditions in the other two species. The most the entire diagnosis and comparisons by Cheneval (1987) distinctive feature of the proximal humerus of focused on differences with the species of the genus Anas. C. sansaniensis is the shape of its caput humeri that is Therefore, the diagnosis by Cheneval (1987) is not valid widened notably in its ventral half (in caudal view). for intrageneric comparisons. As a result, we provide a Given that widening, the distal margin of the caudal new diagnosis for this species, partially based on the surface of the caput humeri is distinctly more sigmoidal proximal humerus as the most distinctive element in (dorsally concave and ventrally convex) in C. sansanien- many ducks, and Chenoanas in particular. sis than in C. deserta and particularly C. asiatica. Our A partial coracoid from the early late Miocene locality study of the individual variation of the caput humeri of Atzelsdorf in Austria has been identified as Anas cf. indicates that this structure is very stable in wild popu- sansaniensis by Gohlich€ (2009). Indeed, this specimen lations of ducks, and thus the unusual morphology of resembles the above described coracoid from Tagay in the caput humeri in C. sansaniensis supports its separate size and general morphology. However, the coracoid from specific status. Atzelsdorf (examined by NVZ in 2012) differs from Tagay Two distal humeri of C. sansaniensis are known from specimen in lacking well-developed concavities within the Sansan; the paralectotype and one additional specimen sulcus m. supracoracoidei. These concavities are charac- MNHN SA 1249. Both correspond in size with those of teristic of the coracoid of C. asiatica as well. Thus, modern Anas platyrhynchos, and thus probably indicate although the specimen from Atzelsdorf may represent a similar humeral proportions in Chenoanas and modern closely-related form, it is obviously belongs to a separate species of Anas. The top surface of the tuberculum species, in agreement with the younger (late Miocene) age supracondylare ventrale faces rather distally, whereas it of this specimen. A fossil egg from the Zellertal in Ger- faces more distocranially in Anas, and cranially in some many, which was attributed to Anas sansaniensis (Ammon primitive anatines (e.g. Dendrocygna and Anser). The 1918, Lambrecht 1933), has an early Miocene age (MN 1; 320 PAPERS IN PALAEONTOLOGY, VOLUME 4 see Gohlich€ 2017) and thus is definitively too old to rep- to assess accurately given widespread mosaic evolution resent the genus Chenoanas. (i.e. homoplasy) in early-diverging taxa. To partly over- We note that we were unable to locate and examine come this limitation, we have coded all Chenoanas species the following specimens from Sansan: MNHN SA 14010 and specimens as a single operational taxonomic unit for (humerus), 1319 and 10277 (scapulae). Herein they are this first attempt at a phylogenetic analysis of this genus assigned to C. sansaniensis following Cheneval (1987, group. This approach allows us to take into account mor- 2000), but their taxonomic assessment requires confirma- phological information from as many skeletal elements as tion. One scapula from Sansan (MNHN SA 1282) is possible, but at the same time it means that the resulting smaller and may represent yet another taxon. Cheneval phylogenetic position of Chenoanas should be regarded (1987, 2000) assigned to ‘Anas’ sansaniensis a number of with caution and as just an initial assessment. However, bones from the middle Miocene of La-Grive-Saint-Alban we find this approach favourable since it is the only pos- (France) – these specimens were never described or fig- sible way to increase robustness in testing relationships of ured. Examination of these materials by NVZ in 2017 this taxon at this time. indicates that they belong to more advanced ducks (prob- While conducting the phylogenetic analyses, we have ably of the genus Anas s.l.) and Tadorna. found that the resulting topology of the strict consensus tree and the position of Chenoanas are sensitive to the taxonomic Occurrence. Late early to earliest middle Miocene (MN 5) composition of the analyses. The first analysis (original Wor- of eastern Siberia, Russia (Tagay locality; Baikal) and thy (2009) matrix with new outgroups and one new taxon, middle Miocene (MN 6) of France (Sansan). Chenoanas) produced eight most parsimonious trees, each 1268 steps in length (CI 0.19; RI 0.60). The topology of the strict consensus tree was generally consistent with that pub- Chenoanas sp. lished by Worthy (2009), but with lower resolution at some Figure 4N, O nodes. On this tree, Chenoanas is in a polytomy with Aix, Hymenolaimus, Stictonetta, Chenonetta, relatives of Oxyura Referred material. PIN 4869/164, cranial fragment of ster- (see Worthy & Lee 2008), Anatini, Tadornini and Mergi- num; Sharga locality (Mongolia). ni+Aythyini (Fig. 5A). The addition of Marmaronetta and Pteronetta to the previous analysis did not affect the position Description. A cranial fragment of sternum from Sharga (speci- of Chenoanas (tree length 1301; not shown). As in the origi- men PIN 4869/164) is similar in size to that of recent Anas nal study, most branches received bootstrap support value acuta, and thus may belong to either Chenoanas deserta or below 50. Marmaronetta and Pteronetta were recovered as C. asiatica. This sternal fragment was mentioned earlier as sister taxa occupying a position similar to that of Chenoanas Anatidae gen. indet. (Zelenkov 2012) but has not been described in the above described polytomy. The exclusion of Manuher- or figured previously. This specimen differs from extant Aix, and ikia, Pinpanetta and Dunstanetta from the initial analysis thus may not be referred to the fossil species Aix praeclara from resulted in a better resolved strict consensus of four most the same deposits (Zelenkov & Kurochkin 2012) because it lacks parsimonious trees (length 1221), fully consistent with the a distinct notch where the spina interna would occur (Fig. 4). In previously published tree (Worthy 2009). On that tree, Che- this new specimen, the spina interna is represented by a very shallow depression cranially and a rudimentary tubercle dorsally noanas is sister to Aix (not shown). The addition of Mar- (similar to the state in extant Anas). On the dorsal surface of maronetta and Pteronetta to the previous analysis and matrix the corpus sterni, there is one rather large pneumatic foramen, did not change the position of Chenoanas in the strict con- positioned close to the cranial end, as in Anas. The spina externa sensus of eight most parsimonious trees (tree length 1254; is broken at its base, but was apparently similar to that of Anas, Fig. 5B). An unconstrained analysis of the Worthy (2009) because taxa with an absent (e.g. Aythya) or rudimentary (Aix) dataset places Chenoanas outside the clade of diving taxa, spina externa exhibit a different morphology of this area. but near modern non-diving Aix, Stictonetta, Mala- corhynchus, and the presumably non-diving (Worthy & Lee 2008) fossil genus Mionetta (tree length 1283; not shown). PHYLOGENETIC RESULTS From these phylogenetic analyses, we can conclude that Chenoanas probably does not belong to crown groups of We appreciate that the phylogenetic position of taxa that Tadornini, Aythyini, Mergini, but may be a part of basal are known only from isolated elements is often difficult Anatini. Topologies lacking fossil taxa have lesser

FIG. 5. Results of phylogenetic analyses. A, the strict consensus of eight most parsimonious trees resulting from analysis of the Wor- thy (2009) dataset with inclusion of Chenoanas, Megapodius and Lithornis. B, the strict consensus of eight most parsimonious trees resulting from analysis of the Worthy (2009) dataset with inclusion of Chenoanas, Megapodius, Lithornis, Pteronetta and Marmaronetta, and with several fossil taxa excluded. Numbers indicate nodes with bootstrap support above 50. See text for details. ZELENKOV ET AL.: MIOCENE DUCK CHENOANAS 321 322 PAPERS IN PALAEONTOLOGY, VOLUME 4 explanatory power since they contain fewer taxa and 2012). All of these widely-distributed taxa are waterbirds, fewer potentially unique combinations of characters closer and thus their presence in both humid subtropical to the base of various anatid radiations. However, we regions of Western Europe and more arid landscapes of note that the consensus tree resulting from the analysis Central Asia may be explained by their associations with with pruned fossil taxa has a better resolution, similar to bodies of water regardless of the broader surrounding that published by Worthy (2009). This tree is also similar environments (similar to the present day distribution of to molecular trees for Anatidae in that Tadornini forms a Tadorna species in Eurasia, which are present in both clade with Anatini, Aythyini, Mergini and Aix (Sun et al. western Europe and the arid Tibetan Plateau; see Stidham 2017). However, the relative position of various clades is et al. 2015). However, we note that representatives of the different in the osteologically based phylogenies which are three genera, found in Sharga (Palaelodus, Protomelanitta based on dataset of Worthy (2009), and molecular phylo- and Chenoanas) are different from their closest relatives genies (e.g. Gonzalez et al. 2009; Sun et al. 2017). These found outside central Asia, and hence are treated as sepa- differences generally concern interrelationships of Anseri- rate species. This implies at least some degree of geo- nae and Dendrocygninae, as well as the position of Mer- graphical differentiation within wide ranges of the gini and Aythyini relative to Anas s.l. Nevertheless, these corresponding genera, which is expected given a supposed discordances are apparently not relevant to the phyloge- high degree of environmental differentiation across Eura- netic position of Chenoanas, which appears not to fall sia. within either of these clades. The three known species of Chenoanas have different stratigraphical distributions. C. sansaniensis is known from MN 5 zone (late early Miocene to earliest middle DISCUSSION Miocene) of East Siberia and the middle Miocene MN 6 of France. The other two species, C. deserta and C. asiat- The new fossil specimens from Siberia (Russia), Mongo- ica, are known only from the MN 7+8 zone of Mongolia lia, and China described above, together with the revised and adjacent Inner Mongolia (China). Note that systematic position of previously known ‘Anas’ sansanien- C. sansaniensis is not only the oldest species, but is some- sis from France, indicate a wide Eurasian distribution of what intermediate morphologically between the other the primitive apparently non-diving ducks of the genus two, and thus may be an ancestor of the late middle Mio- Chenoanas in the late early and middle Miocene (17– cene species. 11 Ma). This broad geographical distribution is compara- Current data support an Asian origin of the genus Che- ble with the wide present-day geographical ranges of noanas (or at least C. sansaniensis); in western Europe many extant anatid genera (such as Cygnus, Anas and more primitive ducks (Mionetta sp.) persisted throughout Aythya) and thus indicates either a similar degree of eco- MN 5 (Gohlich€ 2002). The presence of the predominately logical plasticity/variability of these primitive ducks, or Asiatic genus Chenoanas in Sansan (MN 6) agrees with similar environmental/habitat conditions across Eurasian the observation that in this particular French locality, a middle latitudes that would facilitate such large (intercon- great influence of Asiatic (‘Tungurian’) mammalian taxa tinental) geographical ranges. The middle Miocene avian is traceable (Mirzaie Ataabadi et al. 2013). A great simi- fauna of Mongolia includes a number of presumably larity between snake faunas from the Tagay locality (from endemic genus-level taxa, including galliforms, waterfowl which C. sansaniensis is known) and those from early to and herons (reviewed in Zelenkov 2016a), pointing to middle Miocene of Europe has also been previously noted some level of endemism of the interior Asian avifauna (Rage & Danilov 2008). Other components of the middle during the late middle Miocene. This endemic aspect of Miocene herpetofauna were similarly widespread in Eur- the faunas of Central Asia may be related to an increased ope and Asia (Vasilyan et al. 2016, 2017). However, the level of aridity inferred for the late middle Miocene of age of Sansan (and hence biozone MN 6, for which it is a Asia in general (Flower & Kennett 1994; Liu et al. 2009). reference locality) is still debated. Sen (1997) dated this However, a growing body of evidence indicates that some locality 15–15.2 Ma, which is not supported by more genus-level taxa of central Asian birds indeed had a wide recent research. Agustı et al. (2001) estimated the base of geographical distribution. These new records include the zone MN 6 to be 13.7 Ma, and K€alin & Kempf (2009) almost cosmopolitan flamingo-like Palaelodus (Zelenkov documented a very good correlation between Sansan and 2013) and the diving duck Protomelanitta that was the Swiss locality Niderwis which they dated as 14.1 Ma. described recently from roughly coeval sediments in This temporal interval, between 13.8 and 14.7 Ma, marks North America (Stidham & Zelenkov 2017). Our present the climatic transition from the MMCO and is character- study adds the medium-sized duck Chenoanas to this list, ized by high-amplitude global climate variations (Hol- a genus which was originally described from the middle bourn et al. 2014). Climatic changes in the late middle Miocene Sharga locality in Western Mongolia (Zelenkov Miocene caused the re-emergence of the arid belt in the ZELENKOV ET AL.: MIOCENE DUCK CHENOANAS 323 interior regions of Asia (Flower & Kennett 1994). Prieto from both diving and non-diving sides, such as the mod- & Rummel (2016) documented the westward spread of ern taxa Mergus, Lophodytes and Malacorhynchus, as well faunal associations at around 13.8 Ma in western Europe. as Aythya australis (Woolfenden 1961; Worthy & Lee Undoubtedly, the inferred immigration of Asiatic water- 2008; Stidham 2015). Indeed, morphology does not birds to western Europe during this time interval corre- always predict dietary or behavioural predilections in sponds with this broader palaeobiogeographical trend. avian taxa as demonstrated by the recently documented Details of avian palaeogeography across Eurasia dur- predation of songbirds by Anas platyrhynchos with its ing the MMCO and soon after that time remain largely generalized morphology (Petrovan & Leu 2017). Never- obscured because fossil bird localities of middle Mio- theless, we still favour a hypothesis that Chenoanas was a cene age are almost unknown for a territory ranging generalized dabbling duck: aside from the pneumatized from eastern Europe to eastern Kazakhstan. One of the pneumotricipital fossa, Chenoanas in all known bone pro- few exceptions is the recently described very small duck portions is very close to the living mallard. In the fossil ?Mioquerquedula sp. from the northern Caucasus, which bird assemblage from the Sharga locality in Mongolia, is most likely to belong to a taxon initially established Chenoanas co-occurs with several diving taxa (Zelenkov in Mongolia (Zelenkov 2017). The discovery of Chenoa- 2011) which are all smaller and whose remains are much nas in both western Europe and central Asia adds to more common. This further supports an idea that Che- the emerging picture that the avifaunas from the climat- noanas differed ecologically from those diving taxa. ically warm intervals of the Miocene (early to middle Miocene) in western Europe and north/central Asia Acknowledgements. The senior author thanks Rene Allain shared many taxa. In addition to the species mentioned (Paris), Christine Levefre (Paris), Gerald Mayr (Frankfurt-Am- € above, a primitive grebe and parrot, recorded recently Main), Ursula Gohlich (Vienna), Emmanuel Robert (Lyon), from the late early Miocene of Siberia (Zelenkov 2015, Cecile Mourer-Chauvire (Lyon), Antoine Louchart (Lyon), Dieter Sieges (Stuttgart), Oliver Rauhut (Munich), Carl Mehling 2016b), have relatives in western and central Europe. and Mark Norell (New York), Mark Florence (Washington DC), These data allow us to propose that an avian-based bio- Andrey Panteleyev (Saint Petersburg), as well as Arkady B. geographical realm similar to the modern Palearctic Savinetsky (Moscow) for access to osteological and palaeonto- region might already have been present across this terri- logical collections. We thank Willi Hennig Society for providing tory in the late early and middle Miocene. At present, access to the TNT software. Laboratory work by NVZ, NVM, these biogeographical links are among waterbird taxa and NVV was supported by the Russian Foundation for Basic only, and the affinities of arboreal and terrestrial avian Research (grant 17-04-01162). TAS is supported by the National taxa across the region are unclear and understudied. Natural Science Foundation of China (NSFC41772013) and the Additionally, there are not enough data to determine if Chinese Academy of Sciences (CAS, XDPB05). TAS and QL are this early Neogene Palearctic avifauna is ancestral to the funded by the National Natural Science Foundation of China modern Palearctic one, or if the modern avifauna is (NSFC41472025) and the Strategic Priority Research Program of the Chinese Academy of Sciences (CAS, XDB03020501). We fur- derived from taxa which immigrated into the territory ther thank our referees, Trevor Worthy and Gerald Mayr, for during the late Miocene and Pliocene. However, our valuable comments on the manuscript. data demonstrate that the widely distributed mammalian taxa in the Miocene of Eurasia (e.g. Hipparion) were not alone and at least some birds had similarly wide DATA ARCHIVING STATEMENT geographical ranges. Recognition and study of these broader biogeographical patterns requires palaeontolo- The published work and the nomenclature act it contains have been gists to examine comparative fossil material from registered in ZooBank: http://zoobank.org/References/7C84F17C- around the globe, not just those close to a particular 7EB9-4B51-9110-48F127E2138F locality or even on just one continent. The unconstrained analysis and general morphological Editor. Andrew Smith similarity to Anas, Callonetta and Tadornini indicate that Chenoanas was at most not a specialized diver, if a diver at all. Diving adaptations can often be traced in the hind- REFERENCES limb anatomy of ducks (Kurochkin 1968; Worthy & Lee AGUSTI, J., CABRERA, L., GRACES, M., KRIJGSMAN, 2008) but the corresponding skeletal elements are very W., OMS, O. and PARES, J. M. 2001. A calibrated mammal poorly known for Chenoanas. One of the most universal scale for the Neogene of Western Europe. State of the art. features linked to diving adaptations is the lack of the Earth-Science Reviews, 52, 247–260. extensive pneumacity within the ventral pneumotricipital AMMON, L. VON 1918. Terti€are Vogelreste von Regensburg fossa (well-pneumatized in Chenoanas), but even this fea- und die jungmioc€ane Vogelwelt. Abhandlungen des naturwis- ture is not a universal proxy, as exemplified by exceptions senschaftlichen Vereins zu Regensburg, 12,1–69. 324 PAPERS IN PALAEONTOLOGY, VOLUME 4

BAUMEL, J. J., KING, A. S., BREAZILE, J. E., EVANS, HOWARD, H. 1964. Fossil anseriformes. 233–326.InDELA- H. E. and VANDEN BERGE, J. C. 1993. Handbook of COUR, J. (ed.) Waterfowl of the world. Country Life, London. avian anatomy: Nomina Anatomica Avium. 2nd edn. Publica- HUGUENEY, M., BERTHET, D., BODERGAT, A.-M., tions of the Nuttall Ornithological Club, 23, Cambridge, MA, ESCUILLIE, F., MOURER-CHAUVIRE, C. and WAT- 779 pp. TINNE, A. 2003. The Oligocene-Miocene boundary in BRODKORB, P. 1964. Catalogue of fossil birds. Part 2 Limagne: faunal changes in the mammals, birds and ostracods (Anseriformes through Galliformes). Bulletin of the Florida from the different levels of Billy-Crechy (Allier, France). Geo- State Museum, Biological Sciences, 8, 195–335. bios, 36, 719–731. CHENEVAL, J. 1987. Les Anatidae (Aves, Anseriformes) du KALIN,€ D. and KEMPF, O. 2009. High-resolution stratigra- Miocene de France. Revision systematique et evolution. Docu- phy from the continental record of the Middle Miocene ments des Laboratoires de Geologie, Lyon, 137–156. Northern Alpine Foreland Basin of Switzerland. Neues Jahr- - 2000. The avifauna of Sansan. Memories du Museum buch fur€ Geologie und Pal€aontologie, Abhandlungen, 254, 177– national d’Historie naturelle, 183, 321–388. 235. DICKINSON, E. C. and REMSEN, J. V. Jr (eds) 2013. The KLEMENTIEV, A. M. and SIZOV, A. V. 2015. New record Howard and Moore complete checklist of the birds of the of anchithere (Anchitherium aurelianense) in the Miocene of world, Vol. 1: Non-passerines. Aves Press, Eastbourne, UK, 461 Eastern Siberia, Russia. Russian Journal of Theriology, 14, 133– pp. 143. ERBAJEVA, M. and ALEXEEVA, N. 2013. Late Cenozoic KUROCHKIN, E. N. 1968. Locomotion and hind limb mor- mammal faunas of the Baikalian Region: composition, phology of swimming and diving birds. Unpublished PhD the- biochronology, dispersal, and correlation with Central Asia. sis, Paleontological Institute, Moscow, 256 pp. [in Russian] 495–507.InWANG, X., FLYNN, L. J. and FORTELIUS, LAMBRECHT, K. 1933. Handbuch der Palaeornithologie. M. (eds). Fossil mammals of Asia: Neogene biostratigraphy and Gebruder€ Borntraeger, Berlin, 1024 pp. chronology. Columbia University Press. LEACH, W. E. 1820. Eleventh room. 65–70. In Synopsis of the FLOWER, B. P. and KENNETT, J. P. 1994. The middle Mio- contents of the British Museum. 17th edn. British Museum cene climatic transition: East Antarctic ice sheet development, (Natural History), London. deep ocean circulation and global carbon cycling. Palaeogeogra- LINNAEUS, C. 1758. Systema natura per regna tria naturae, phy, Palaeoclimatology, Palaeoecology, 108, 537–555. secundum classes, ordines, genera, species, cum characteribus, FULTON, T. L., LETTS, B. and SHAPIRO, B. 2012. Multi- differentiis, synonymis, locis. 10th edn. Vols 1–3. Laurentii ple losses of flight and recent speciation in steamer ducks. Salvii, Holmiae. Proceedings of the Royal Society B, 279, 2339–2346. LIU, L., ERONEN, J. T. and FORTELIUS, M. 2009. Signif- GOHLICH,€ U. B. 2002. The avifauna of the Miocene Fossil- icant mid-latitude aridity in the middle Miocene of East Asia. Lagerstatte Sandelzhausen (Bavaria, Southern Germania). Zit- Palaeogeography, Palaeoclimatology, Palaeoecology, 279, 201– teliana, 22, 169–190. 206. - 2009. Aves. Annalen des Naturhistorischen Museums in LYDEKKER, R. 1891. Catalogue of the fossil birds in the British Wien, A, 111A, 509–513. Museum (Natural History). Taylor & Francis, London, XXVII -2017. Catalogue of the fossil bird holdings of the Bavarian + 368 pp. State collection of palaeontology and geology in Munich. Zit- MAYR, G. 2008. Phylogenetic affinities and morphology of the teliana, 89, 331–349. late Eocene anseriform bird Romainvillia stehlini LEBE- GOLOBOFF, P. A. and CATALANO, S. A. 2016. TNT ver- DINSKY, 1927. Neues Jahrbuch fur€ Geologie und Pal€aontologie, sion 1.5, including a full implementation of phylogenetic mor- Abhandlungen, 248, 365–380. phometrics. Cladistics, 32, 221–238. -2017. Avian evolution: The fossil record of birds and its pale- GONZALEZ, J., DUTTMAN,€ H. and WINK, M. 2009. obiological significance. John Wiley & Sons, 293 pp. Phylogenetic relationships based on two mitochondrial genes -and PAVIA, M. 2014. On the true affinities of Chenornis and hybridization patterns in Anatidae. Journal of Zoology, graculoides Portis, 1884, and Anas lignitifila Portis, 1884—an 279, 310–318. albatross and an unusual duck from the Miocene of Italy. HILGEN, F. J., LOURENS, L. J., VAN DAM, J. A., BEU, Journal of Vertebrate Paleontology, 34, 914–923. A. G., BOYES, A. F., COOPER, R. A., KRIJGSMAN, MILNE-EDWARDS, A. 1867–1871. Recherches anatomiques W., OGG, J. G., PILLER, W. E. and WILSON, D. S. et paleontologiques pour servir a l’histoire des oiseaux fossiles de 2012. The Neogene period. 923–978.InGRADSTEIN, F. la France. Victor Masson et fils, Paris. M., OGG, M. D., SCHMITZ, J. G. and OGG, G. M. MIRZAIE ATAABADI, M., LIU, L., ERONEN, J. T., (eds). The geologic time scale 2012. Elsevier. BERNOR, R. L. and FORTELIUS, M. 2013. Continental- HOLBOURN, A., KUHNT, W., LYLE, M., SCHNEI- scale patterns in Neogene mammal community evolution and DER, L., ROMERO, O. and ANDERSEN, N. 2014. Mid- biogeography: a Europe-Asia perspective. 629–655.In dle Miocene climate cooling linked to intensification of WANG, X., FLYNN, L. J. and FORTELIUS, M. (eds). eastern equatorial Pacific upwelling. Geology, 42,19–22. Fossil mammals of Asia: Neogene biostratigraphy and chronol- HOUDE, P. W. 1988. Paleognathous birds from the early ogy. Columbia University Press. Tertiary of the northern hemisphere. Publications of the Nuttall MITCHELL, K. J., WOOD, J. R., SCOFIELD, R. P., LLA- Ornithological Club, 22, Cambridge, MA, 148 pp. MAS, B. and COOPER, A. 2014. Ancient mitochondrial ZELENKOV ET AL.: MIOCENE DUCK CHENOANAS 325

genome reveals unsuspected taxonomic affinity of the extinct America (Nevada) with affinities to Mongolian taxa. Alcher- Chatham duck (Pachyanas chathamica) and resolves diver- inga, 41, 222–230. gence times for New Zealand and sub-Antarctic brown teals. -WANG, X., LI, Q. and NI, X.-J. 2015. A shelduck cora- Molecular Phylogenetics & Evolution, 70, 420–428. coid (Aves: Anseriformes: Tadorna) from the arid early Pleis- MLIKOVSKY, J. 1988. Notes on the brains of the middle Mio- tocene of the Qinghai-Tibetan Plateau, China. Palaeontologia cene birds (Aves) of Hanhenberg (F.R.G.). Casopis pro Miner- Electronica, 18.2.24A,1–10. alogii a Geologii, 33,53–61. SUN, Z., PAN, T., HU, C., SUN, L., DING, H., WANG, -2002. Cenozoic birds of the world. Part 1: Europe. Ninox H., ZHANG, C., JIN, H., CHANG, Q., KAN, X. and press, Praha, 406 pp. ZHANG, B. 2017. Rapid and recent diversification patterns MOURER-CHAUVIRE, C. 2008. Birds (Aves) from the in Anseriformes birds: inferred from molecular phylogeny and Early Miocene of the Northern Sperrgebiet, Namibia. Memoir diversification analyses. Plos One, 12, e0184529. of the Geological Survey of Namibia, 20, 147–167. SYROMYATNIKOVA, E. V. 2016. Anurans of the Tagay -BERTHET, D. and HUGUENEY, M. 2004. The late locality (Baikal Lake, Russia; Miocene): Bombinatoridae, Oligocene birds of the Crechy quarry (Allier, France), with a Hylidae, and Ranidae. Russian Journal of Herpetology, 23, description of two new genera (Aves: Pelecaniformes: Pha- 145–157. lacrocoracidae, and Anseriformes: Anseranatidae). Senckenber- TESAKOV, A. S. and LOPATIN, A. V. 2015. First Record of giana Lethaea, 84, 303–315. Mylagaulid Rodents (Rodentia, Mammalia) from the Miocene PARIS, P. 1912. Oiseaux fossiles de France. Revue Francßaise d’- of Eastern Siberia (Olkhon Island, Baikal Lake, Irkutsk Region, gie, 37, 283–298. Russia). Doklady Biological Sciences, 460,23–26. PETROVAN, S. O. and LEU, M. 2017. Hunting and con- VASILYAN, D., BOHME,€ M. and KLEMBARA, J. 2016. sumption of passerine birds by wild Mallards (Anas platyrhyn- First record of fossil Ophisaurus (Anguimorpha, Anguidae) chos). Waterbirds, 40, 187–190. from Asia. Journal of Vertebrate Paleontology, 36, e1219739. € PRIETO, J. and RUMMEL, M. 2016. Some considerations -ZAZHIGIN, V. S. and BOHME, M. 2017. Neogene on small mammal evolution in Southern Germany, with amphibians and reptiles (Caudata, Anura, Gekkota, Lacertilia, emphasis on Late Burdigalian-Earliest Tortonian (Miocene) and Testudines) from the south of Western Siberia, Russia, cricetid rodents. Comptes Rendus Palevol, 15, 837–854. and Northeastern Kazakhstan. PeerJ, 5, e3025. QIU, Z.-D. 1996. Middle Miocene micromammalian fauna from WAGLER, J. G. 1831. Einige Mittheilungen uber€ Thiere Mexi- Tunggur, Nei Mongol. Academic Press, Beijing, 216 pp. cos. Isis von Oken, 5, 510–535. QIU, Z., QIU, Z., DENG, T., LI, C., ZHANG, Z., WANG, X., QIU, Z. and OPDYKE, N. D. 2003. Litho-, bio-, WANG, B. and WANG, X. 2013. Neogene land mammal and magnetostratigraphy and paleoenvironment of Tunggur stages/ages of China: toward the goal to establish an Asian Formation (Middle Miocene) in Central Inner Mongolia, land mammal stage/age scheme. 29–90.InWANG, X., China. American Museum Novitates, 3411,1–31. FLYNN, L. J. and FORTELIUS, M. (eds). Fossil mammals WOOLFENDEN G. E. 1961. Postcranial osteology of the of Asia: Neogene biostratigraphy and chronology. Columbia Waterfowl. Bulletin of the Florida State Museum, Biological University Press. Sciences, 6,1–129. RAGE, J.-C. and DANILOV, I. G. 2008. A new Miocene WORTHY, T. H. 2009. Descriptions and phylogenetic relation- fauna of snakes from eastern Siberia, Russia. Was the snake ships of two new genera and four new species of Oligo-Mio- fauna largely homogenous in Eurasia during the Miocene? cene waterfowl (Aves: Anatidae) from Australia. Zoological Comptes Rendus Palevol, 7, 383–390. Journal of the Linnean Society, 156, 411–454. SEN, S. 1997. Magnetostratigraphic calibration of the European -and LEE, M. S. Y. 2008. Affinities of Miocene waterfowl Neogene mammal chronology. Palaeogeography, Palaeoclima- (Anatidae: Manuherikia, Dunstanetta and Miotadorna) from tology, Palaeoecology, 133, 181–204. the St Bathans Fauna, New Zealand. Palaeontology, 51, 677– STIDHAM, T. A. 2015. Re-description and phylogenetic 708. assessment of the Late Miocene ducks Aythya shihuibas and -DEGRANGE, F. J., HANDLEY, W. D. and LEE, M. Anas sp. (Aves: Anseriformes) from Lufeng, Yunnan, China. S. Y. 2017. The evolution of giant flightless birds and novel Vertebrata PalAsiatica, 53, 335–349. phylogenetic relationships for extinct fowl (Aves, Gal- -and HILTON, R. P. 2016. New data on stiff-tailed duck loanseres). Royal Society Open Science, 4, 170975. evolution and dispersal from a new species of diving duck ZELENKOV, N. V. 2011. Diving ducks from the middle Miocene (Anseriformes: Anatidae: cf. Oxyurinae) from the Miocene of Western Mongolia. Paleontological Journal, 45, 191–199. High Rock Caldera in north-west Nevada, USA. Papers in -2012. A new duck from the middle Miocene of Mongolia, Palaeontology, 2,41–58. with comments on Miocene evolution of ducks. Paleontologi- - and NI, X.-J. 2014. Large anseriform (Aves: Anatidae: cal Journal, 46, 520–530. Romainvilliinae?) fossils from the Late Eocene of Xinjiang, -2013. Cenozoic phoenicopteriform birds from Central Asia. China. Vertebrata PalAsiatica, 52,98–111. Paleontological Journal, 47, 1323–1330. -and ZELENKOV, N. V. 2017. North American-Asian -2015. A primitive grebe (Aves, Podicipedidae) from the aquatic bird dispersal in the Miocene: evidence from a new Miocene of Eastern Siberia (Lake Baikal, Olkhon Island). Pale- species of diving duck (Anseriformes: Anatidae) from North ontological Journal, 49, 521–529. 326 PAPERS IN PALAEONTOLOGY, VOLUME 4

-2016a. Evolution of bird communities in the Neogene of -- 2015. Class Aves. 86–290.InKUROCHKIN, E. N., Central Asia, with a review of the Neogene fossil record of LOPATIN, A. V. and ZELENKOV, N. V. (eds). Fossil ver- Asian birds. Paleontological Journal, 50, 1421–1433. tebrates of Russia and adjacent countries: fossil reptiles and -2016b. The first fossil parrot (Aves, Psittaciformes) from birds: Part 3. GEOS, Moscow. Siberia and its implications for the historical biogeography of -and MARTYNOVICH, N. V. 2013. A rich bird fauna Psittaciformes. Biology Letters, 12, 20160717. from the Miocene locality Tagay (Olkhon Island, Baikal -2017. The finds of fragmentary bird skeletons in the middle Lake). Archives of the Menzbier Ornithological Society, 2, Miocene of Northern Caucasus. Doklady Biological Sciences, 73–93. 477, 223–226. -and PANTELEYEV, A. V. 2015. Three bird taxa (Aves: -and KUROCHKIN, E. N. 2012. Dabbling ducks (Aves: Anatidae, Phasianidae, Scolopacidae) from the Late Miocene Anatidae) from the middle Miocene of Mongolia. Paleontolog- of the Sea of Azov (Southwestern Russia). Pal€aontologische ical Journal, 46, 421–429. Zeitschrift, 89, 515–527.

APPENDIX Marmaronetta 00[02]101012? 12010?0011 11[01]1[02]11[01]22 2000112011 1302[01]110[01]1 1?21211021 0111120110 1101111001 0211231020 1100011?[12]1 [12]1011122?0 [01] Codings of newly added taxa 01111?1?2 002??000?0 0??[01]011[12][01]3 ?2000?11?0 Megapodius reinwardt 0001000000 1100??0?21 1100?00022 21101? Chenoanas ?????????? ?????????? ????????22 ???[01]1???11 ?30311???? 2[01]11 02011000[01]1 1?1121[01]001 0100100000 0000001000 0211?10012 ?????????? ?????????? ?????????? ????????11 2?1??????? 102[01]0?1000 0110101001 ?11?011000 00000001?0 20300000?? ?????????? ?????????? ???101?2?? ?????????? ???0211?0? 0110110100 Pteronetta 00010001[01]3 12010?0211 1101111022 2000112011 Lithornis promiscuus 0010100001 2?00??0?10 0100?00021 13020110[01]1 1?2111[01]021 0111120110 1101110012 0211131 1100112011 ?0?3101011 1?00000012 02001010?0 1000011000 [01]20 1100121?[12]1 11001122?1 00111[01]02?2 10[02]??000?0 10001?110? 0110120011 ?11?112101 00000020?? 003?0010?? ??? [01]??[01]011[12][01][12] ?2100?10?0 0001?0? 001002211?