Shargainosorex angustirostris, Zazhigin & Voyta, 2018

Zazhigin, Vladimir S. & Voyta, Leonid L., 2018, A new middle Miocene crocidosoricine shrew from the Mongolian Shargain Gobi Desert, Acta Palaeontologica Polonica 63 (1), pp. 171-187 : 174-182

Shargainosorex angustirostris sp. nov.

Figs. 2A, C , 3A–C, E, F, 4A 1, A 2, 5–7, 10С; SOM 3: figs. 1A, 2; SOM 5: fig. 1.

ZooBank LSID: http://zoobank.org/act: 5CFB271C-422E-4814-8DF6- 822151CF3845

Etymology: From the Latin angusti, narrow and rostris, snout.

Type material: Holotype: ZISP 104323 (in PZC: GIN 959 /1010) left dentary fragment with i1, p4–m3 (see details in SOM 1: I) . Paratypes (22 fragments of premaxillary and maxillary bones, mandibles and teeth): ZISP104324/1002, 1007, 1009, 1045, 1048–50, 1055–56, 1061, 1065, 1068–69, 1071, 1073, 1080, 1097–98, 1108, 1114, 1116, 1164 (see details in SOM 1: I).

Type locality: Sharga 2, about 20 km SW from Sharga Village , northern slope of the Ikhe-Baerkhe-Tologoi Rock [N46°11’ E 95°03’], Shargain Gobi Desert, Mongolia .

Type horizon: Lower part of Oshin Suite, middle Miocene ( MN7–8 , ~12.5–11.2 Ma ). Material was collected by VSZ during the summer of 1978, and VSZ and Evgenii V. Devjatkin (Geological Institute, Russian Academy of Sciences, Moscow, Russia) during the summer of 1979 .

Material.— Type material and 195 fragments (left, right fragments of skull; left, right upper isolated teeth; left dentary, semi-mandible fragments; left lower isolated teeth; right dentary, semi-mandible fragments; right lower isolated teeth) from the type locality (see details in SOM 1: I–III).

Measurements.—See SOM 2 and SOM 7.

Diagnosis.—Small-sized shrew, with two lower antemolars (а1, р4); the first lower incisor has two denticles on the cutting edge with slightly developed notch before first denticle, its narrow ectocingulid is well developed along the posterior edge of the crown; the single root of a1 is shifted buccally relative to the longitudinal axis of the tooth crown; p4 double-rooted, with two arms of the posterocristid that extend posteriorly from the protoconid; ectocingulid of lower molar well-developed; the first upper incisor has a massive crown and a rather small and wedge-shaped root; its talon is complicated, with a visible notch on its base, and a well-developed medial cusp on the talon; 5 antemolars in upper tooth row (A1–A5); the crown of the third upper antemolar is strongly compressed disto-mesially; the teeth are notably pigmented; the mental foramen lies below the protoconid of m1.

Description.— Dentition: The teeth are markedly pigmented. The dental formula is 1.5.1.3/1.1.1.3. The first upper incisor has a massive crown, and a rather small and wedge-shaped root. The apex of the incisor is not fissident. The buccal cingulum is moderately wide and well defined, and extending dorsally to the upper part of crown. The talon is complicated, with a visible notch on its base, and well-developed medial cusp of talon. The lateral side of the root has a triangle-like groove, whereas the medial side is a smooth surface. The upper outline of crown-root’s junction is stepped (see Fig. 2A 1 , A 2 ). Apex and talon’s apex are visibly pigmented.

→ Fig. 3. Crocidosoricine shrews Shargainosorex angustirostris gen. et sp. nov. from middle Miocene Sharga 2 locality, Mongolia (A–C, E, F), and Miosorex grivensis ( Deperet, 1892) from middle Miocene of La Grive St. Alban, France (D). A. ZISP 104324/1069 (paratype), right maxilla in occlusal view (A 1, A 4); A 3 in occlusal (A 2) and buccal (A 3) views. B. ZISP 104324/1045 (paratype), left maxilla in occlusal view. C. ZISP 104324/1061 (paratype), right maxilla (mirrored) with greatly worn P4–M3, in buccal (C 1, C 2) and occlusal (C 3) views. D. ZISP 103200/4, right maxilla (mirrored) in occlusal view. E. ZISP 104324/1050 (paratype), left maxilla in occlusal view. F. ZISP 104324/1049 (paratype), left maxilla with greatly worn P4, in occlusal view (F 1). Grey areas in F 2 indicate occlusal wear facets of P4; arrows show different directions of wear. Photographs (A 1 –A 3, B, C 1, C 3, D, E, F 1), explanatory drawings (A 4, C 2, F 2). Scale bars 1 mm.

Only one fragment of the right premaxilla-maxilla with single-rooted A3 and alveoli of I1–A2, A4–A5 is present. Antemolar A3 has a single, slightly worn cusp, its crown being strongly compressed disto-mesially (Fig. 3A 2) and the buccal cingulum being broad (Fig. 3A 3). Alveolus of A1 is large and round in transverse section, with a developed longitudinal base for the anterior part of the root (i.e., small groove with relatively high walls); alveolus of A2 is the largest in the row, oval-shaped (i.e., compressed disto-mesially), and with a developed longitudinal base in the anterior part; the oval-shaped root could indicate a similarly compressed crown. The relative position of the alveolus of A2, and alveolus and crown of A3 indicate that A3 is likely overlapping the posterior part of the crown of A2. The alveoli of A4 and A5 are round, without additional features, the first one slightly larger than second one (probably alveolus of A4 similar in size to alveolus of A3) (see Fig. 3A 1, A 4). Hence, the relative size of the antemolars is likely A1≤A2>A3≥A4>A5.

P4 is sub-trapezoidal in shape, markedly compressed disto-mesially, with a moderately anterior shifting of the developed parastyle and protocone; the hypocone as a distinct bulb is absent, the hypoconal flange being surrounded by a narrow ridge without any bulges; posterior emargination is well developed (Fig. 3B); the upper outline in lateral view is undulate, with a visible mesial inflection ( Fig. 4A 2 : e); buccal cingulum extends along the upper edge of tooth, sometimes with a short gap in its mesial part. In frontal view, the lingual part of P4 is strongly inclined relative to the axis of the antero-buccal root ( Fig. 4A 1 : a); the angle of relative inclination is less than 42° (it is the minimum value compared to other studied species).

The first and second upper molars slightly decrease in size front to back, but the width of M1 is lesser than M2 by AW mean values, see SOM 2: table 1). M1 and M2 are sub-rectangular in outline. The paracone and metacone of M1 are high and narrow; height of the paracone is about /2 that of the metacone; the protocone is massive and triangular in shape, with developed pre- and postprotocrista; the hypocone is absent, but there is a moderate bulge at the beginning of the hypoconal flange ridge. The styles of M1 are straight, or the parastyle is slightly hooked, e.g., for M1–M2 (see Fig. 4B 2 ). The posterior emargination of M1 is more weakly developed than in P4, but stronger than in M2 see values of PE-indices in SOM 2: table 1). Ectocingulum is well developed along the upper edge of M1; precingulum is short and lies below the protocone. In frontal view, the protocone tip position is notably higher relative to the tip of the paracone ( Fig. 4C : b, d).

In general, the morphology of the second molar is similar to the first with differences only seen in the relative height of the paracone (about 3/4 of the metacone’s height), a weaker posterior emargination, and a more weakly developed ectocingulum (Fig. 3C 2, E).

M3 is relatively short, with a slight emargination of the outline between para- and mesostyle; the paracone is the largest, its parastyllar crest being notably longer than the mesostyllar crest; the metacone is weakly developed; the protocone is large with a wide base.

The first lower incisor is straight, with two denticles on the cutting edge (bicuspulate), with a weakly developed, but defined notch before the first denticle (i.e., notch between the i1–a1 junction and first denticle); the notches of the cutting edge after the first and second denticles are equally developed; the tip of the tooth is slightly curved upwards ( Figs. 2C , 5A 1, A 2). The ectocingulid is narrow and well developed along the posterior edge of the crown ( Fig. 2C ). The longitudinal axes of the incisor crown and root coincide.

The known isolated a1 is moderately worn, with the main (protoconid) cusp notably shifted anteriorly; two arms of the posterocristid extend posteriorly from the protoconid; the buccal arm (Fig. 5G 1: d) extends near the medial line of the crown ends with a well-defined bulge very close to the posterior edge of the tooth (Fig. 5G 1: e, G 2); the degree of development of the lingual arm is not known with certainty (tooth is worn), but it presumably ends without any bulge and very close to the posterolingual part of the tooth (Fig. 5G 1). The wide ectocingulid surrounds only the posterior half of the tooth (Fig. 5G 2); the narrow entocingulid is well developed. The single root is shifted buccally relative to the longitudinal axis of the tooth crown (Fig. 5G 1).

The p4 has an asymmetrical tetrahedral-like shape; it is double-rooted with a high protoconid and two relatively short arms of the posterocristid; the buccal arm is longer (by 1/3 of the length) than the lingual arm; the buccal arm ends in a visible cusplet, far before reaching the posterobuccal corner of tooth (Fig. 5B). The ecto- and entocingulid are wide and well developed.

The lower molars are graded in size: the first molar is the largest, the second slightly smaller, and the third even smaller (Fig. 5A). The trigonid of m1 is relatively narrow and longer than in m2 (SOM 2: table 1); with comparable length

Fig. 5. Crocidosoricine shrews Shargainosorex angustirostris gen. et sp. nov. from middle Miocene Sharga 2 locality, Mongolia (A, B, D, E, G), and → Miosorex grivensis ( Deperet, 1892) from middle Miocene of La Grive St. Alban, France (C, F). A. ZISP 104323 (holotype), left dentary fragment, in buccal (A 1), lingual (A 2), and occlusal (A 3, A 4) views. B. ZISP 104323 (holotype), left fourth lower premolar in occlusal view. C. ZISP 103200/1, left fourth lower premolar in occlusal view, showing buccal arm of posterocristid extending before entocingulid of p4 (contact indicated by arrow). D. ZISP 104324/1114 (paratype), fragment of the left semi-mandible, whole mandibular ramus with slightly damaged angular process, in lateral (D 1) and medial

D 2) views. E. ZISP 104324/1108 (paratype), right condyle in articular surface view. F. ZISP 103200/2, left condyle (mirrored) in articular surface view.

G. ZISP 104324/1097 (paratype), right first lower antemolar in occlusal (G 1) and buccal (G 2) views. Abbreviations: a, line indicating the longitudinal axis of tooth crown; b, dotted line with right-turned arrow indicates notable anterior tilting of protocristid of m1 relative line a; c, dotted line with left-turned arrow indicates weak tilting of protocristid of m2; d, buccal arm of the posterocristid; e, cusplet that ends buccal arm of the posterocristid; f, deep wear facet of a1. Scale bars 1 mm.

of talonids (mean = 0.46 mm) of both molars, the trigonid of m1 is 60.4% of the total length of the tooth, and the trigonid of m2 = 56.9%. The paraconid of m1 extends anteriorly; the protoconid is high; the metaconid is developed and slightly shifted relative to the lingual outline of the tooth base; the hypoconid is lower (by 1/2 of its height) than the protoconid; the entoconid is well developed, the entocristid reaches the base of the metaconid; the well-defined hypolophid ends in a narrow hypoconulid; the hypoconulid is widely separated from the entoconid, and slightly inclined backward; the posterobuccal ridge is weakly developed and ends far before reaching the ectocingulid; the buccal re-entrant valley is well defined; the protocristid is moderately inclined relative to the longitudinal axis of the crown (Fig. 5A 3: b). The pre-, ecto-, postero-, and entocingulid are well developed.

The lower second molar repeats the morphology of m1, the differences being a relatively shorter trigonid and a generally shorter tooth; the protocristid is longer than in m1 and is almost perpendicular to the longitudinal axis of the crown Fig. 5A 3: c).

The lower third molar has a developed trigonid, and a talonid reduced in size; the talonid is narrow, with a shallow basin; the entoconid is weakly developed; the entocristid is short and does not reach the base of the metaconid; the hypoconulid is not developed; the posterobuccal ridge is weakly developed, but almost reaches the ectocingulid; the protocristid is perpendicular to the longitudinal axis of crown (similar to m2); the postcingulid is weakly developed (Fig. 5A).

Tooth pigmentation: Because of taphonomic conditions, not all investigated teeth display pigmentation. Many teeth with worn tips (unpigmented) were subjected to chemical infiltration and formed a dark, unicolour secondary pigment. Some upper and lower teeth demonstrate a visible reddish soricine-like pigment on the main cusps (SOM 3: fig. 2) teeth. In addition, to detect lost pigmentation, we investigated several teeth under transmitted UV lights; this revealed that pigmented areas were notably smaller than in Sorex daphaenodon Thomas, 1907 (SOM 3: fig. 1). Examination of all visibly pigmented and UV analysed teeth allowed us to reconstruct the tooth colouration of S. angustirostris gen. et sp. nov. ( Fig. 6 ).

Skull fragments: Only a few fragments of maxilla with small parts of palatal bone, and one fragment of maxilla with a small part of premaxilla, were present in the studied material. S. angustirostris gen. et sp. nov. has a moderately wide lateral wall of the infraorbital canal, similar in relative size to crocidurine species. Its lacrimal foramen is at the height of the M1–M2 joint, and lies centred in the lateral wall of the infraorbital canal. The end of the antero-lingual root of M1 goes into the infraorbital canal with a relatively large foramen (Fig. 3C 1, C 3). The relatively small zygomatic process of the maxilla extends weakly laterally; its tip is at the level of M2 metastyle (Fig. 3C 2). A fragment of rostrum with alveoli of I1–A2, A4–A5, and A 3 in situ shows in frontal view a “pectiniform” base of the antemolar row (not shown in figures), i.e., probably a narrow and strongly concave hard palate along the row.

Mandible: The horizontal ramus of the lower jaw is narrow and moderately gracile; its lower margin runs in a very shallow convex inward curve. The mental foramen lies in a slightly tilted groove under the protoconid of m1 (Fig. 5A 1). The mandibular ramus is moderately high; the coronoid process is slightly inclined anteriorly; the coronoid spicule is short and well developed; the lateral temporal fossa is shallow and notably limited by longitudinal ridges (Fig. 5D 1); the internal temporal fossa is deep and clearly delineated (Fig. 5D 2). The condylar process is moderately massive; the pterygoid spicule is weakly developed and lies below the margin of the upper sigmoid notch; its articular surface is sub-triangular, with a narrow contact between the upper and lower facets, and developed buccal emargination (Fig. 5E), i.e., it is crocidurine-like. The angular process is long and narrow, without developed ridges; its tip is unknown.

We investigated the number of lower antemolar alveoli and p4 roots because some dentary fragments with lost antemolars display three alveoli: the middle alveolus is the smallest, and perhaps corresponds to vestigial a2. A longitudinal section of the left dentary fragment ( Fig. 7A ) reveals two differently sized roots of p4, and an anterior alveolus of a1. Three alveoli ( Fig. 7B ) between i1 and m1 of S. angustirostris gen. et sp. nov. correspond to a single-rooted procumbent a1 and a double-rooted p4.

Variation.— Sharga 2 sample homogeneity: To determine whether the studied fossil remains belong to a single population, i.e., whether we deal with one species, we applied statistical analyses that included an estimate of sample homogeneity in comparison to samples from local populations of Crocidura shantingensis Miller, 1901 and Sorex minutus Linnaeus, 1766 (see details in SOM 1: V), which were collected during several months of a single year. Interspecies comparisons of the test values allowed us to assess whether fossil remains were buried for a relatively short time in a restricted area. A normality test (SOM 2: tables 1–3) shows homogeneity in most metrics of the studied remains of Shargainosorex angustirostris gen. et sp. nov. from Sharga 2 (W = 0.928 –0.991, p> 0.05). A visual examination of the simple graphs (specimens/values) revealed rather narrow limits of their variation, which were comparable with representative samples of C. shantungensis and S. minutus (SOM 2: table 4). The next step of the assessment of homogeneity was estimation of variability limits using coefficient of variation (CV%). Analysis of 36 measurements (n> 5) showed comparable CV values between fossil material and the two Recent samples (SOM 2: table 5).

Metric variations : Normality tests and coefficient variation obtained for Shargainosorex angustirostris gen. et sp. nov. show several characters with wide variability limits, such as MRWc (W = 0.846, p <0.05), LLF (W = 0.876, p <0.05), according to a Shapiro-Wilk test (SOM 2: table 1), and features of lower (TAL[m1], TRW[m1]) and upper (PE[P4]) teeth, according to the values of their coefficient variations (SOM 2: table 5).

Age variations : The sample contains teeth with different degrees of age-related wear. Some teeth demonstrated heavily worn occlusal surfaces, which we can describe for one specimen (Fig. 3C 2). P4 has two wide wear facets on the postparacrista; one prolonged wide facet from the parastyle to the protocone; and a narrow facet along the ridge of the hypoconal flange (Fig. 3C 2, F). M1 has a mostly worn paracone and protocone; the tip of metacone is less worn than the premetacrista; the hypoconal ridge is slightly worn. In general, the tooth displays two wear facets: a broad buccal one, and a weaker protoconal one. M2 has similar wear conditions to M1, but weaker wear of the paracone and more heavy wear of the postprotocrist (Fig. 3C 2). These observations further allow us to use mesowear methods ( Koenigswald 2016; Hooker 2017) to compare S. angustirostris gen. et sp. nov. with other extinct ( Miosorex ) and Recent genera (unpublished material).

Qualitative features: Most variability was found in tooth pigmentation and the shape of the condylar articulation surface. Pigmentation depends on taphonomic conditions and the chemical composition of the deposits, as mentioned above. As a result, we observe pigmented teeth (from weak orange to notably reddish colouration), unpigmented teeth uncoloured patterns throughout the crown from grey to cream to black), and spotted teeth (areas filled with different shades of grey, brown, and black). Condylar surfaces reveal several morphotypes (SOM 5: fig. 1) with lower facets tilted relative to upper facets, and upper facets varying in width. In general, we observe typical morphotypes (Fig. 5E, SOM 5: fig. 1A, D, E), and some deviating morphotypes (SOM 5: fig. 1B, C, F). Other features do not vary notably. Namely, the mental foramen is sometimes slightly shifted anteriorly, not reaching paraconid level of m1; the protocristid of m2 demonstrates a fairly large tilting of the protocristid, like in m1 (Fig. 5A 3: b), and, as a result, some isolated lower molars were misidentified. The mandibular foramen is slightly shifted anteriorly in part of the specimens.

Comparisons.— Shargainosorex gen. nov. differs from Srinitium (a1–a5, p4), Taatsinia (a1–a4, p4), Tavoonyia , Ulmensia , Crocidosorex , Oligosorex , Carposorex , Clapasorex , Lartetium (a1–a3, p4), Florinia , Miocrocidosorex , Soricella , Meingensorex , Miosorex (a1, a2, p4) in the number of lower antemolars: a1, p4. Although the number of lower antemolars is not known for the genera Aralosorex and Turiasorex , Shargainosorex gen. nov. differs from Aralosorex in the relative length of the posterocristid arms of p4 ( Lopatin 2004: 212, see diagnosis); namely, the new genus is demonstrated as having a longer (by 1/2 of the length) buccal arm than the lingual arm, and the buccal arm not connecting with the ectocingulid; and in the absence of a connection between the posterobuccal crest of protoconid and ectocingulid of m1–m3 ( Aralosorex conditions see Lopatin 2004: 213–215, fig. 2a). Moreover, Shargainosorex gen. nov. differs from Turiasorex in proportions and specific features of the teeth, e.g., absence of the middle and posterior parts of the entocingulid of lower molars, and the transverse elongation of the upper molars (Van Dam et al. 2001: 301, fig. 1). It differs from the genera of Crocidurinae in having pigmented teeth and five upper antemolars. It differs from the genera of Soricinae in several crocidurine-like features, such as the shape of the mandibular condyle, the shape of the mandibular symphysis, the width of the lateral wall of infraorbital canal, and the composition of the mental foramen (situated in the inclined groove).

Shargainosorex angustirostris gen. et sp. nov. differs from M. grivensis (in addition to the main differential character) in the general proportions of I1. Specifically, M. grivensis displays a smooth dorsal outline, shorter buccal cingulum, comparable size of crown and root, and an elongated shape of the lateral groove of its root (see conditions in Fig. 2B ). M. grivensis displays a bulged ridge in the hypoconal flange of P4 (Fig. 3D), a relatively straight upper outline and intermittent buccal cingulum, a comparably obtuse angle between the lingual part of P4 and its root ( S. angustirostris gen. et sp. nov., angle α ≤ 42° vs M. grivensis , angle β ≈ 81°), the relative positions of the parastyle to the protocone of P4, and the paracone to the protocone of M1 ( S. angustirostris gen. et sp. nov has a higher position of both protocones; cf. Figs. 4A, C and 4B, D ); in several features of the lower incisor, where M. grivensis displays a more hooked tip of i1 (a deeper distal notch after the second denticle), and the ectocingulid expanding downwards ( Fig. 2D ); in features of the occlusal surface of p4: M. grivensis has longer arms of the posterocristid that form a wide and clearly delineated basin, and the buccal arm reaches the postero-buccal margin of the tooth (Fig. 5C, “arm”).

Shargainosorex angustirostris gen. et sp. nov. differs from Miosorex desnoyersianus ( Lartet, 1851) and is similar to the M. grivensis conditions of the occlusal shape of p4 and the more posterior position of the mental foramen. On the other hand, M. desnoyersianus displays a condition of the cutting margin of i1 and a development of its ectocingulid similar to the Shargain shrew (see Engesser 2009: 17, figs. 6b, f).

Stratigraphic and geographic range.—At present, restricted to the type locality and horizon.

Figures

Fig. 2. Crocidosoricine shrews Shargainosorex angustirostris gen. et sp. nov. from middle Miocene Sharga 2 locality, Mongolia (A, C), and Miosorex grivensis (Deperet, 1892) from middle Miocene of La Grive St.Alban, France (B, D). A. ZISP 104324/1068 (paratype), right I1 (mirrored) in buccal view. B. ZISP 103200/6, left I1 in buccal view; dashed line and grey area on B2 indicate damaged tip and base of talon. Arrows indicate crown-root junction, stepped (A2), or smooth (B2). C. ZISP 104323 (holotype), fragment of left i1 in buccal view. D. ZISP 103200/7, left i1 in buccal view.Arrowheads indicate first and second denticles of i1; dotted line indicates notch until first denticle. Photographs (A1–D1), explanatory drawings (A2–D2).

Fig. 1. Map showing location of Govi-Altai Aimag in south-western Mongolia (A) and Shargain Gobi Depression within Govi-Altai Province (B). C. Satellite image of the Sharga Village area, where Shargainosorex angustirostris gen. et sp. nov. was discovered.

Fig. 4. Specific features of crocidosoricine shrews Shargainosorex angustirostris gen. et sp. nov. from middle Miocene Sharga 2 locality, Mongolia (A, B) and Miosorex grivensis (Deperet, 1892) from middle Miocene of La Grive St. Alban, France (C, D) compared to Recent red-toothed, Sorex araneus Linnaeus, 1758 (E), and white-toothed, Suncus etruscus (Savi, 1822) (F). A. ZISP 104324/1055 (paratype), left fourth upper premolar associated with maxilla fragment (mirrored), in anterior (A1) and buccal (A2) views. B. ZISP 103200/4, right fourth upper premolar associated with maxilla fragment, in anterior (B1) and buccal (B2) views. C. ZISP 104324/1050 (paratype), left first upper molar associated with maxilla fragment (mirrored), in anterior view. D. ZISP 103200/5, right first upper molar associated with maxilla fragment, in anterior view. E, F. Transversal sections of rostral parts of Recent shrews through P4 (level of anterioro-buccal root) (E1, F1), and M1 (level of anterior roots) (E2, F2). Abbreviations: a, inclination line of the hard palatine relative to antero-buccal root axis of P4; b, line of a paracone position relative to a protocone line (d) along antero-lingual root axis of M1; e, the undulated upper margin of P4 in buccal view; f, line of the ground-in surface (shown only for S. etruscus due to degree of its tooth preservation); α–δ angles, values of the hard palatine relative inclination for each species (α ≤ 42°; ss ≈ 81°; γ ≈ 62°; δ ≈ 66°).

Fig. 6. Tooth pigmentation of crocidosoricine shrew Shargainosorex angustirostris gen. et sp. nov. from middle Miocene Sharga 2 locality, Mongolia. A. ZISP 104324/1080 (paratype), right M1 (mirrored), with pigmentation of main cusps, in occlusal view. B. ZISP 104325/1121, right dentary fragment mirrored) in buccal view. C.ZISP 104324/1069 (paratype), right A3 in occlusal view. D. ZISP 104324/1055 (paratype), left maxilla in occlusal view. E. ZISP 104324/1068 (paratype), right I1 (mirrored) in buccal view. F. ZISP 104323 (holotype), left dentary fragment in buccal view. Dashed lines (C, D, F) indicate supposed pigment parts. Optical photographs (A, B), diagrammatic reconstructions of teeth coloration (C–F). C–F not to scale.

Fig. 7. Number and relative position of the lower antemolar alveoli of crocidosoricine shrew Shargainosorex angustirostris gen. et sp. nov. from middle Miocene Sharga 2 locality, Mongolia. A. ZISP 104324/1098 (paratype), longitudinal (parasagittal) section of the left dentary fragment in buccal view. B. ZISP 104324/1002 (paratype), right dentary fragment (mirrored) in occlusal (B1) and buccal (B2) views.