Material of Gomphotherium wimani has been reported in several localities after Hopwood (1935).However,most of the findings are isolated cheek teeth,and the morphology and stratigraphy of this species remain unclear to researchers.Here we reported an incomplete juvenile cranium and cheek teeth from Linxia Basin,northwestern China.The new material is well comparable with the holotype and helps to cognize the morphology,taxonomy and stratigraphic range of the rarely known species.Proboscidea Illiger,1811 Gomphotheriidae Hay,1922 Gomphotherium Burmeister,1837 Gomphotherium wimani (Hopwood,1935) (Figs.3-5;Tables S1-2) Holotype PMU M 3649,a palate bearing both M2-M3 tooth rows and fully worn left M1 (Hopwood,1935:pl.5,fig.3;Tobien et al.,1986:fig.7).Referred material in the present study IVPP V 23559,a relatively complete juvenile cranium bearing both P3-M3 tooth rows,lacking the posterior part of the brain case,from the Shanggou locality in Nalesi Township,Dongxiang County (LX 1002,N 35°34′30.9″,E 103°27′19.7″),the bottom of the Hujialiang Formation,approximately 13.5 Ma.IVPP V 18759,left and right M2,right M3,right m2,left m3,quite presumably belonging to the same individual;from the Daoheigou locality in Dalang Township,Hezheng County (LX 0209,N 35°27′06.1″,E 103°23′08.1 ″),the middle part of the Dongxiang Formation,approximately 15-13.5 Ma.Amended diagnosis Revised after Hopwood (1935) Medium-sized Gomphotherium;interloph(id)s moderately to relatively largely anteroposteriorly crowded;anterior and posterior pretrite central conules subdivided into approximately three conules and thick-crest-like;weak posttrite central conules present;posttrite half lophs of upper molars subdivided;posttrite mesoconelets of lower molars small;the development of cementum variable,from absent to moderately developed;crown height slightly larger than that of G.annectens group and G.angustidens group.Comparison The Linxia material can be attributed to Gomphotherium wimani based on the following characters:anteroposteriorly moderately crowded lophs;strong subdivision and thick-crested form of pretrite central conules;subdivision of posttrite half lophs;presence of posttrite central conules;relatively high crown in Gomphotherium.The Linxia material completes the morphology of lower cheek teeth and cranium of G.wimani.G.wimani differs from the members of G.annectens group (Tassy,1985,2013) in the complete pretrite trefoils (in G.annectens group pretrite central conules are not well-developed,much less than subdivision).It differs from members of pygmy Gomphotherium group (Sanders et al.,2010) in much larger size (Fig.5).It differs from the members of G.angustidens group (except for G.subtapiroideum) in strong subdivision of posttrite half lophs and pretrite central conules,and in the equivalent anterior and posterior pretrite central conules of the upper molars (in G.angustidens group,the posterior central conule is larger than the anterior one of the upper molar,see Tassy,1985,2013).It differs from G.subtapiroideum in relatively crowded loph(id)s and presence of posttrite central conules (G(o)hlich,2010).As belonging to the G.productum group (Wang,2014),G.wimani resembles the common members in this group except that the loph(id)s are highly crowded in other members (Osborn,1926,1936;G(o)hlich,1998).Furthermore,G.wimani slightly differs from G.browni in the presence of posttrite central conules;from G.steiheimense in not well-developed the last loph(id)s in M3 and m3;and from G.productum in lower crown height.Amendment material and age of G.wimani The hypodigm of G.wimani is heterogeneous.In the hypodigrn,a tooth from Quantougou (Chuan Tou Kou) (PMU M 3056) was identified as an m3 (Hopwood,1935:24,pl.6,fig.1) (Fig.4E).However,it is an M3 of Platybelodon grangeri,based on the follows reaseons:the contour is narrow (characteristic for amebelodontids) (Fig.5) (Wang et al.,2013b);the tooth shows somewhat anancoidy (characteristic for amebelodontids),and the pretrite half loph is more mesial to the posttrite half loph (characteristic for upper molars) (Wang et al.,2013b);only posterior posttrite central conules develop and the anterior ones are missing (characteristic for Platybelodon) (Wang et al.,2013b);the posterior pretrite central conules invade the extoflexid (characteristic for Platybelodon,especially for P.grangeri,see Wang et al.,2013b);the third anterior pretrite central conule is strong but the posterior one is missing (characteristic for P.grangeri) (Wang et al.,2013b);the mid-axis is slightly buccally convex,which is also observed in some specimens ofP.grangeri (Fig.4F).Another M2 from Quantougou can be safely attributed to G.wimani.The age of the Quantougou locality is approximately 13 Ma."Trilophodon cf.T.wimani" from Yushe (Teilhard and Trassaert,1937:pl.12,figs.1,2) was re-identified as Sinomastodon praeintermedius (Wang et al.,2016)."Gomphotherium wimani" from Diaogou (Qiu et al.,1981:pl.2,fig.1) is potentially a tooth of amebelodontids,because of the relatively narrow contour and the well-developed posttrite central conules (Fig.4D).The ml of G.wimani from Nanyu (Wang et al.,2013a:figs.3,4) resembles the Daoheigou m3 in the narrowness of first pretrite half loph,in the moderately to highly subdivision of pretrite central conules,in the small posttrite mesoconelets,in the presence of posttrite central conules.The Nanyu dp4 resembles the Daoheigou m2 in the widening of the tooth from the second lophids.Therefore,attribution to G.wimani of the Nanyu material is guaranteed.The mandibular fragment of the Nanyu G.wimani has a circular alveolus of lower tusk,which assures that G.wimani is really a Gomphotherium,and not an amebelodontid.The age of the Nanyu locality is approximately 15-13.5 Ma.As the above discussed,the age of G.wimani spans approximately from 15 to 13 Ma,correlated to MN6 and the early MN7/8.

Gomphotherium is a stem taxon of Elephantida that was widespread in Africa, Eurasia, and North America during the Miocene. However, the evolution of this genus is greatly debated because of morphological variation among the species of Gomphotherium. In the present work, we describe a cranium and accompanying material of Gomphotherium from the late middle Miocene Hujialiang Formation of Linxia Basin, China. The new material shows dental similarities to G. subtapiroideum from the middle Miocene of Europe; however, it displays some cranial, mandibular, and dental feature combinations that are distinct from the known species of Gomphotherium. Therefore, a new species, G. tassyi, is established. We further study the phylogeny of Gomphotherium by cladistic analysis and recognize four groups. The most basal G. annectens group' is a paraphyletic group that includes G. annectens, G. cooperi, G. sylvaticum, and G. hannibali. The African taxa, G. libycum and G. pygmaeus, constitute a monophyletic group that has not been named. The G. angustidens group' is a monophyletic group that includes G. inopinatum, G. mongoliense, G. connexum, and G. angustidens. In addition, the 'derived Gomphotherium group,' which includes G. subtapiroideum, G. tassyi, G. wimani, G. browni, G. productum, and G. steinheimense, was widely distributed in Eurasia and North America during the middle and late Miocene.

宁夏同心丁家二沟哺乳动物群是中国中中新世早期最具代表性的地方动物群,但长期以来,对这一动物群产出层位的认识处于模糊和混乱的状态.本文通过对丁家二沟一带新生界地层的划分和对比,将出产丁家二沟动物群的彰恩堡组划分为下、中、上3个层位,其中下部和中部的层位分别产出两个时代不同的动物群:下部的印子岭动物群以Alloptox gobiensis-Protanancus tobieni-Caementodon tongxinensis-Turcocerus sp.1组合为代表,时代对应于欧洲陆相哺乳动物分期的MN5;中部的马二嘴子沟动物群则以Alloptox gobiensis-Platybelodon tongxinensis-Hispanotherium matritense-Turcocerus sp.2组合为代表,时代对应于欧洲陆相哺乳动物分期的MN6;而上部的地层则需要进一步研究划分.同时,丁家二沟地区彰恩堡组的下部层位的时代约为17～ 15Ma,跨越了中中新统的下界,可以考虑在这一地区重新建立中国陆相通古尔阶下界,使其与中中新统的下界相一致.此外,丁家二沟地区北部彰恩堡组与下伏清水营组成不整合接触,南部干河沟组中发育了生长断层,可能代表了这一地区对约20Ma和10Ma青藏高原两次强烈构造事件在东北部的远程响应.

Here we describe a new species of Konobelodon Lambert, 1990 - a poorly known tetralophodont shovel-tusked proboscidean - from the Late Miocene of the Linxia Basin, China. Detailed osteological anatomies of skulls, teeth, and partial postcranial bones of the new taxon, Konobelodon robustus n. sp., are described and detailed morphological comparisons with the other species of Konobelodon (K. atticus (Wagner, 1857) = Mastodon grandincisivus, Schlesinger 1917, and K. britti (Lambert, 1990)) and other gomphotheres are conducted. The skull and jaw-closing muscles of a juvenile individual of the new species are reconstructed and the body mass is estimated based on its limb bones. Phylogenetic analysis of genera within Elephantimorpha results in three most parsimonious trees, of which two support a sister-group relationship between Konobelodon and Platybelodon, within a monophyletic Amebelodontinae. The new results enhance our knowledge on the anatomy and phylogeny of Konobelodon, and indicate pronounced diversification and strong parallel evolution in the amebelodontines.

In this paper, we restudy previously reported material of Gomphotherium connexum and G. shensiensis from China. G. connexum is characterized by the strong posterior pretrite central conules of the upper molars, which are larger than the corresponding anterior ones (at least in the second loph), the narrow interloph(id)s, the high central conules, and the narrow contour of m3. Gomphotherium cf. shensiensis (here is attributed to G. connexum) from the Junggar Basin is more derived than the type material of G. connexum in larger size and heavier cementum. G. connexum is very similar to G. angustidens, which was widely distributed in the Middle Miocene (MN6–8) of Europe. Gomphotherium shensiensis (here is attributed to G. cf. subtapiroideum) shows crest-like elements in the teeth crowns. The posttrite lophs are subdivided and anteroposteriorly compressed, and the interlophs are relatively anteroposteriorly wide. These features are similar to G. subtapiroideum, which occurred in the later Early Miocene to the earlier Late Miocene (MN5–9) of Europe. This revision of Chinese Gomphotherium demonstrates strong similarities in Gomphotherium species between eastern and western Eurasia, representing a continental diffusion of Gomphotherium species across the Palearctic region.