New material of Paukkaungmeryx minutus (Cetartiodactyla, Archaeomerycidae) from the late Middle Eocene Pondaung Formation, Myanmar

doi:10.19615/j.cnki.2096-9899.230522

Abstract

Abstract:

We describe here new dental material from the locality of Myaukse Kyitchaung (Pondaung Formation, central Myanmar) that we refer to the primitive Archaeomerycidae ruminant Paukkaungmeryx minutus Ducrocq et al. (2020). The upper molars are morphologically very similar to those of the holotype and exhibit only slight variations on features like the better development of buccal and lingual cingula. The lower teeth display primitive characters including a simple p4 and bunoselenodont lower molars that lack folds on the back of the trigonid wall. This additional material makes Paukkaungmeryx the second archaeomerycid in Pondaung known by upper and lower teeth material, and documents the apparently complex early evolution of the family.

Key words: Myanmar, Middle Eocene, Pondaung Formation, Cetartiodactyla, Archaeomerycidae, Paukkaungmeryx

摘要：

描述了缅甸中部邦塘组Myaukse Kyitchaung地点原始反刍类古鼷鹿科小包康鼷鹿(Paukkaungmeryx minutus Ducrocq et al., 2020)的牙齿新材料。新材料的上臼齿与正型标本相比形态上仅有微小的变异，如更加发育的颊侧和舌侧齿带。下颊齿具有原始的特征，包括：简单的p4, 下臼齿呈丘月齿型，以及下三角座后壁无“褶”状结构。新材料的发现使Paukkaungmeryx成为邦塘发现的第二个同时保存上、下牙齿的古鼷鹿科成员，也展现了古鼷鹿科早期演化的复杂历史。

关键词: 缅甸, 中始新世, 邦塘组, 鲸偶蹄目, 古鼷鹿科, Paukkaungmeryx

CLC Number:

Q915.876

Stéphane DUCROCQ, Yaowalak CHAIMANEE, Olivier CHAVASSEAU, Aung Naing SOE, Chit SEIN, Jean-Jacques JAEGER. New material of Paukkaungmeryx minutus (Cetartiodactyla, Archaeomerycidae) from the late Middle Eocene Pondaung Formation, Myanmar. Vertebrata Palasiatica, 2023, 61(3): 182-197.

Stéphane DUCROCQ, Yaowalak CHAIMANEE, Olivier CHAVASSEAU, Aung Naing SOE, Chit SEIN, Jean-Jacques JAEGER. 2023, 61(3): 182-197, 缅甸中始新世晚期邦塘组Paukkaungmeryx minutus (鲸偶蹄目，古鼷鹿科)新材料. 古脊椎动物学报.

Figures/Tables 5

Fig. 1 Location map of Kyauk Magyi Kyitchaung and Myaukse Kyitchaung

Fig. 2 Paukkaungmeryx minutus from Myaukse Kyitchaung A, B. MYS-2013-2, right M1-3, in occlusal view; C-F. MYS-2013-1, right p4-m3, in occlusal (C, D), lingual (E) and buccal (F) views. Scale bar equals 5 mm

Fig. 3 Lower premolars and molars of Paukkaungmeryx minutus compared with those of other Dichobunoidae A. MYS-2013-1, right p4-m3; B. Dichobune jehenni (Dichobuninae), right p4-m3, Vil. 1969-92;C. Hyperdichobune langi (Dichobuninae), p4-m3 (composite): left m1-3, Li 1011 (inverted), right p4,Li 1010; D. Eurodexis russelli (Eurodexeinae), m1?3 (composite): right m1, SLP-29-PE 8,right m2, SLP-29-PE 855 and right m3, SLP-29-PE 963; E. Pakkokuhyus lahirii (Dichobunidae), right m1-3, GSI B-766; F. Neochorlakkia myaingensis (Dichobunidae), right m3, MFP-PK2-2019-003;G. Cadutherium kyaukmagyii (Dichobunidae), right alveola of p4, broken m1, talonid of m2 and m3, KM73;H. Hsanotherium parvum (Dichobunidae), right m1, NMMP-KU 0037; I. Haqueina haquei (Dichobunidae), left m2-3, BSPG 1956 II 10 (inverted); J. Chorlakkia hassani (Dichobunidae), left m1-3, GSP-UM 66 (inverted); K. Pakibune chorlakkiensis (Dichobunidae), right m2-3 (composite): right m2, GSP-UM 690 and right m3, GSP-UM 259; L. Elaschitotherium qii (Lantianiinae), p4-m3 (composite): left p4, IVPP V12759.63 (inverted) and left m1-3, IVPP V12759-44 (inverted); M. Diacodexis pakistanensis (Diacodexeidae), left p4-m3, HGSP 300 5003 (inverted); N. Obotherium parvum (Tapirulidae), m1/2-m3 (composite): right m1/2, IVPP V31726 and right m3, IVPP V31727.2. Not to scale

Fig. 4 Lower premolars and molars of Paukkaungmeryx minutus compared with those of other basal ruminants (Tragulidae and Archaeomerycidae) A. MYS-2013-1, right p4-m3; B. Archaeotragulus krabiensis (Tragulidae), p2-m3 (composite): left p2-m2, TF 2997 (inverted), left m3, TF 2989 (inverted); C. Krabitherium waileki (Tragulidae),left p4-m3, BM 07-07-28-6 (inverted); D. Stenomeryx bahinensis (?Tragulidae), right p2-m3,MFP-PK2-2015-1; E. Indomeryx cotteri (Archaeomerycidae), right p4-m3, GSI-B 768;F. Irrawadymeryx pondaungi (Archaeomerycidae), left m1-3, TUDW-20061 (inverted);G. Archaeomeryx optatus (Archaeomerycidae), left p4-m3, AMNH 20311 (inverted);H. Notomeryx besensis (Archaeomerycidae), left p4-m3, IVPP V11480 (inverted); I. Miomeryx altaicus (Archaeomerycidae), right p4-m3, PIN 3110/1226. Not to scale

Fig. 5 Scatter plots of lower and upper teeth measurements of Paukkaungmeryx minutus and other related archaeomerycids Red dot: Paukkaungmeryx minutus (mean values from this work and Ducrocq et al., 2020);Blue dot: Indomeryx arenae (mean values from Tsubamoto et al., 2003); Orange dot: Indomeryx cotteri (mean values from Tsubamoto et al., 2003); Pink dot: Irrawadymeryx pondaungi (values from Métais et al., 2007b); Green dot: Archaeomeryx optatus (mean values from Vislobokova and Trofimov, 2002); Grey dot: Notomeryx besensis (mean values from Guo et al., 1999); Black dot: Xinjiangmeryx parvus (values from Zheng, 1978)

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