Please wait a minute...
Welcome to Visited Vertebrata Palasiatica, Today is Share:
IMAGE/TABLE DETAILS
New fossils of small and medium-sized bovids from the Early Site of Shanshenmiaozui in Nihewan Basin, North China
TONG Hao-Wen, ZHANG Bei, CHEN Xi, WANG Xiao-Min
Vertebrata Palasiatica    2022, 60 (2): 134-168.   DOI: 10.19615/j.cnki.2096-9899.220413
Abstract   (181 HTML34 PDF(pc) (11536KB)(259)  

Shanshenmiaozui site in Nihewan Basin in North China is a recently discovered Early Pleistocene site which yields rich and diverse mammalian fossils. In the fauna, the small and medium-sized bovid fossils are well represented and can be referred to the following taxa: Spirocerus wongi, Gazella sinensis, Ovis shantungensis and Megalovis piveteaui respectively, among which G. sinensis is the dominate species. S. wongi and G. sinensis are mainly represented by horn-cores and partial skull bones as well as mandibles; in addition, metacarpal and/or metatarsal bones were also recognized for all of the four species. The horn-cores are easy to be identified to the species level, while the dentitions and the postcranial bones underwent a series of examinations and comparisons before getting properly determined and referred to the most approximate taxa. Among the postcranial bones, the metapodials, especially to the metacarpal bones special attentions were paid, which are crucial not only for taxonomic identification, but also for phylogenetic and paleoecological reconstructions; the previously misidentified metapodial specimens in Nihewan fauna were reconsidered in this paper. In the SSMZ fauna, the bovid guild is dominated by Gazella and Bison, which indicates steppe was the most important biome in Nihewan Basin during Early Pleistocene.


Fig. 2 Partial skulls, jaw bones and teeth of Spirocerus wongi (A-D) and Ovis shantungensis (E) from SSMZ
A-D. Spirocerus wongi: A. partial skull with horn-cores (IVPP V 28650), B1-B3. juvenile maxilla with DP2-M1 (V 28651), C1-C4. left mandible with dp2-m1 (V 28652.1), D1-D4. partial right mandible with p4-m3 (V 28653); E1-E2. Ovis shantungensis, maxilla with left DP4-M1 and right DP2-4 and M1 (V 28693)
A. anterior view; B1, E1. palatal views; B2, C1, D1, E2. buccal views; C2, D2. lingual views;B3, C3-4, D3-4. occlusal views. The unmarked scale bars equal 20 mm
Extracts from the Article
Skull bones: One partial adult skull ( Fig. 2A) and one partial juvenile skull ( Fig. 2B1-3) can be referred to the the species S. wongi. The adult one has very limited frontal bone, but with almost complete horn-cores of both sides. In front view, the frontal bone shows two moderately developed supraorbital pits which accommodate the two prominent supraorbital foramina which are connecting directly to the anterosuperior corner of the orbit and each has a very large internal opening, even larger than in an ox. The eye socket is very large and deep, and has a trench-like roof with flat superior wall rather than domed as in other taxa. The horn is very close to the orbit, which is only 30 mm apart; the postorbital constriction is also obvious. The cranial width at the horn bases is 149.0 mm, and the two horn-cores are 65.6 mm apart at the base. The frontal sinus (pneumatization) is also quite developed, but the diverticulum doesn’t extend to the cornual process (Fig. 3A2).
Maxilla: One juvenile maxilla with DP2-4 and unfully erupted M1 on both sides ( Fig. 2B1). Except the trench-like anterior part, the palatal surface is quite flat; the palatal widths between DP2, DP3, DP4 and M1 are 37.0, 47.1, 49.0 and 58.9 mm respectively.
Mandible: One partial adult mandible with p4-m3 ( Fig. 2D1-4) and two juvenile partial mandibles ( Fig. 2C1-4) are referred to the species S. wongi. The two juvenile mandibles (IVPP V 28652.1 and V 28652.2) should belong to the same individual because of their exactly similar dental features. One of the juvenile mandible (V 28652.1) retains most of the mandibular body and the ramus, but lacks the angular process and the tip of the coronoid process. The adult partial mandible has the mandibular condyle completely preserved. All the mandibular specimens have no speciality except the moderately pachyostosed mandibular body ( Fig. 2C3, D3), which is similar with those of the extant sumatran serows ( Capricornis sumatraensis).
Deciduous upper teeth ( Fig. 2B3; Table 3): All of the deciduous upper cheek teeth are completely molarized except DP2. DP2 is elongated, but the posterior lobe is relatively reduced and the posterior fossette (or infundibulum) is shallow. The DP3 has much more wider but shorter posterior lobe relative to the anterior one, and the two fossettes are V-shaped in occlusal view; the mesostyle rib is quite pronounced, the lingual wall of the first lobe is roundish. The DP4 has a much more wider anterior lobe relative to the posterior one; the mesostyle rib is also quite pronounced; the lingual wall of the posterior lobe is more roundish relative to the anterior one. The metacone rib is less developed in all three kinds of tooth. The dimensions of the deciduous teeth are shown in Table 3.
Deciduous lower teeth ( Fig. 2C1-4): The dp2 is less complicated; the crown has a rectangle outline but the front portion becomes slightly narrower; the paraconid is crest like; there is no parastylid; the protoconid is robust; the metaconid and hypoconid are equally developed; the entoconid is not developed. Between the protoconid and the metaconid, there exists a shallow valley. The dp3 is much more complicatedly constructed, and larger than dp2 ( Fig. 2C4); the outline is in narrow trapezoid, with the lingual side concave and the narrow portion toward anterior; in front of the paraconid there is a parastylid; the metaconid is very elongated and extended backwards; the valley between parastylid and paraconid is closed, but the valley between the paraconid and metaconid is open; the buccal wall is flat but slightly convex, and the hypoflexid is quite shallow. The dp4 is the most complicated and longest tooth which has three lobes, each lobe has a separate infundibulum, namely anterior, posterior and third fossettid respectively, and the three lobes are nearly equally developed but the second one is slightly more expanded; according to the nomenclature by Bärmann and Rössner (2011), the anterior lobe consists of anterobuccal conid and anterolingual conid, the middle lobe consists of protoconid and metaconid, and the posterior lobe is composed of hypoconid and entoconid respectively; on the buccal side, there is no basal pillars. The lingual cuspids, the parastylid, mesostylid and metastylid are well developed.
Permanent lower teeth ( Fig. 2D1-4; Table 3): Only one partial mandible preserves p4 to m3. The p4 is very advanced in well developed protoconid and metaconid, but other cuspids are extremely reduced; metaconid is column-like but connects with paraconid mesially by a narrow bridge, it doesn’t contact protoconid; there is a narrow and deep groove between metaconid and entoconid. The m1 and m2 are very similar in morphology, except the latter is longer and has more developed goat fold; the infundibulums are very narrow; the lingual cuspids are compressed linguobuccally and the lingual wall is quite flat. The m3 has three lobes, the front two of which are very similar to m2 in shape and size; the third lobe has no infundibulums and is linguobuccally compressed. From the lingual aspect, prominent parastylid and entostylid ribs on m2 and m3 can be seen, and even a rib at the linguo-distal corner of hypoconulid lobe can also be observed, but the mesostylid rib is only slightly developed at the top part of the crown. From the buccal view, no basal pillars can be observed.
Maxilla: One maxilla with left DP4-M1 and right DP2-M1 (IVPP V 28693) ( Fig. 2E1-2) can be referred to Ovis shantungensis. The DP2 is deeply worn and the infundibulum has disappeared. The DP3 is moderately worn, with robust paracone and metacone as well as metaconule, the protocone is less developed, with robust parastyle, the posterior lobe is wider than the anterior one. The DP4 has equally developed main cusps, and the styles are also equally developed; the paracone rib is very robust, the anterior lobe is wider than the posterior one. In form, the M1 is very similar with DP4, but much bigger and more hypsodont. The dimensions of the teeth are shown in Table 3.
Deciduous lower teeth ( Fig. 2C 1-4): The dp2 is less complicated; the crown has a rectangle outline but the front portion becomes slightly narrower; the paraconid is crest like; there is no parastylid; the protoconid is robust; the metaconid and hypoconid are equally developed; the entoconid is not developed. Between the protoconid and the metaconid, there exists a shallow valley. The dp3 is much more complicatedly constructed, and larger than dp2 ( Fig. 2C 4); the outline is in narrow trapezoid, with the lingual side concave and the narrow portion toward anterior; in front of the paraconid there is a parastylid; the metaconid is very elongated and extended backwards; the valley between parastylid and paraconid is closed, but the valley between the paraconid and metaconid is open; the buccal wall is flat but slightly convex, and the hypoflexid is quite shallow. The dp4 is the most complicated and longest tooth which has three lobes, each lobe has a separate infundibulum, namely anterior, posterior and third fossettid respectively, and the three lobes are nearly equally developed but the second one is slightly more expanded; according to the nomenclature by Bärmann and Rössner ( 2011 ), the anterior lobe consists of anterobuccal conid and anterolingual conid, the middle lobe consists of protoconid and metaconid, and the posterior lobe is composed of hypoconid and entoconid respectively; on the buccal side, there is no basal pillars. The lingual cuspids, the parastylid, mesostylid and metastylid are well developed. ...

Deciduous lower teeth ( Fig. 2C 1-4): The dp2 is less complicated; the crown has a rectangle outline but the front portion becomes slightly narrower; the paraconid is crest like; there is no parastylid; the protoconid is robust; the metaconid and hypoconid are equally developed; the entoconid is not developed. Between the protoconid and the metaconid, there exists a shallow valley. The dp3 is much more complicatedly constructed, and larger than dp2 ( Fig. 2C 4); the outline is in narrow trapezoid, with the lingual side concave and the narrow portion toward anterior; in front of the paraconid there is a parastylid; the metaconid is very elongated and extended backwards; the valley between parastylid and paraconid is closed, but the valley between the paraconid and metaconid is open; the buccal wall is flat but slightly convex, and the hypoflexid is quite shallow. The dp4 is the most complicated and longest tooth which has three lobes, each lobe has a separate infundibulum, namely anterior, posterior and third fossettid respectively, and the three lobes are nearly equally developed but the second one is slightly more expanded; according to the nomenclature by Bärmann and Rössner ( 2011 ), the anterior lobe consists of anterobuccal conid and anterolingual conid, the middle lobe consists of protoconid and metaconid, and the posterior lobe is composed of hypoconid and entoconid respectively; on the buccal side, there is no basal pillars. The lingual cuspids, the parastylid, mesostylid and metastylid are well developed. ...

Deciduous lower teeth ( Fig. 2C 1-4): The dp2 is less complicated; the crown has a rectangle outline but the front portion becomes slightly narrower; the paraconid is crest like; there is no parastylid; the protoconid is robust; the metaconid and hypoconid are equally developed; the entoconid is not developed. Between the protoconid and the metaconid, there exists a shallow valley. The dp3 is much more complicatedly constructed, and larger than dp2 ( Fig. 2C 4); the outline is in narrow trapezoid, with the lingual side concave and the narrow portion toward anterior; in front of the paraconid there is a parastylid; the metaconid is very elongated and extended backwards; the valley between parastylid and paraconid is closed, but the valley between the paraconid and metaconid is open; the buccal wall is flat but slightly convex, and the hypoflexid is quite shallow. The dp4 is the most complicated and longest tooth which has three lobes, each lobe has a separate infundibulum, namely anterior, posterior and third fossettid respectively, and the three lobes are nearly equally developed but the second one is slightly more expanded; according to the nomenclature by Bärmann and Rössner ( 2011 ), the anterior lobe consists of anterobuccal conid and anterolingual conid, the middle lobe consists of protoconid and metaconid, and the posterior lobe is composed of hypoconid and entoconid respectively; on the buccal side, there is no basal pillars. The lingual cuspids, the parastylid, mesostylid and metastylid are well developed. ...

Deciduous lower teeth ( Fig. 2C 1-4): The dp2 is less complicated; the crown has a rectangle outline but the front portion becomes slightly narrower; the paraconid is crest like; there is no parastylid; the protoconid is robust; the metaconid and hypoconid are equally developed; the entoconid is not developed. Between the protoconid and the metaconid, there exists a shallow valley. The dp3 is much more complicatedly constructed, and larger than dp2 ( Fig. 2C 4); the outline is in narrow trapezoid, with the lingual side concave and the narrow portion toward anterior; in front of the paraconid there is a parastylid; the metaconid is very elongated and extended backwards; the valley between parastylid and paraconid is closed, but the valley between the paraconid and metaconid is open; the buccal wall is flat but slightly convex, and the hypoflexid is quite shallow. The dp4 is the most complicated and longest tooth which has three lobes, each lobe has a separate infundibulum, namely anterior, posterior and third fossettid respectively, and the three lobes are nearly equally developed but the second one is slightly more expanded; according to the nomenclature by Bärmann and Rössner ( 2011 ), the anterior lobe consists of anterobuccal conid and anterolingual conid, the middle lobe consists of protoconid and metaconid, and the posterior lobe is composed of hypoconid and entoconid respectively; on the buccal side, there is no basal pillars. The lingual cuspids, the parastylid, mesostylid and metastylid are well developed. ...

Deciduous lower teeth ( Fig. 2C 1-4): The dp2 is less complicated; the crown has a rectangle outline but the front portion becomes slightly narrower; the paraconid is crest like; there is no parastylid; the protoconid is robust; the metaconid and hypoconid are equally developed; the entoconid is not developed. Between the protoconid and the metaconid, there exists a shallow valley. The dp3 is much more complicatedly constructed, and larger than dp2 ( Fig. 2C 4); the outline is in narrow trapezoid, with the lingual side concave and the narrow portion toward anterior; in front of the paraconid there is a parastylid; the metaconid is very elongated and extended backwards; the valley between parastylid and paraconid is closed, but the valley between the paraconid and metaconid is open; the buccal wall is flat but slightly convex, and the hypoflexid is quite shallow. The dp4 is the most complicated and longest tooth which has three lobes, each lobe has a separate infundibulum, namely anterior, posterior and third fossettid respectively, and the three lobes are nearly equally developed but the second one is slightly more expanded; according to the nomenclature by Bärmann and Rössner ( 2011 ), the anterior lobe consists of anterobuccal conid and anterolingual conid, the middle lobe consists of protoconid and metaconid, and the posterior lobe is composed of hypoconid and entoconid respectively; on the buccal side, there is no basal pillars. The lingual cuspids, the parastylid, mesostylid and metastylid are well developed. ...

Other Images/Table from this Article