Cifellitherium suderlandicum, Martin & Averianov & Schultz & Schellhorn & Schwermann, 2022

Martin, Thomas, Averianov, Alexander O., Schultz, Julia A., Schellhorn, Rico & Schwermann, Achim H., 2022, First spalacotheriid and dryolestid mammals from the Cretaceous of Germany, Acta Palaeontologica Polonica 67 (1), pp. 155-175 : 159-162

publication ID	https://doi.org/ 10.4202/app.00914.2021
persistent identifier	https://treatment.plazi.org/id/EB57E55D-9154-655D-FF1A-FE80FC3AF602
treatment provided by	Felipe
scientific name	Cifellitherium suderlandicum
status	sp. nov.

Treatment

Cifellitherium suderlandicum sp. nov.

Figs. 3–5 View Fig View Fig View Fig .

Zoobank LSID: LSID urn:lsid:zoobank.org:act:4195BDBD-1C75-4D0D-899D-252B1D2B7266

Etymology: From the medieval name Suderlande for the Sauerland region of Germany where Cifellitherium was found.

Holotype: WMNM P82305 , right lower molar.

Type locality: Fissure filling within the Busche quarry near Balve, Sauerland, North Rhine-Westphalia, Germany.

Type horizon: Barremian–Aptian (Lower Cretaceous).

Material.— Holotype and left upper molars ( WMNM P82308 , P82302 ) from the type locality and horizon.

Diagnosis.—Medium to large sized spalacotheriid. Referred to Spalacotheriidae based on the combination of the following characters: acute angulation of principal cusps of upper (ranging from 40° to 54° on different teeth) and lower (55°) molars (derived); postvallum/prevallid shearing surfaces complete, extending on entire respective aspects on the upper and lower molars (derived); distinctive cusp B and well developed hook-like parastyle present (plesiomorphic); pronounced lingual cingulum; lower molar asymmetrically high crowned (labial side higher than lingual) with well developed proto-, para-, and metaconid; single distal talonid cusp d small and without heel, sitting at the lingual side of trigonid (derived); distal cuspule d overlapping labially with mesial cuspule e of the succeeding molar (derived); only one small mesial cingular cusp e present, distinct and in lingual position (derived); prominent lingual and labial cingulid, the latter interrupted above the interradical notch (derived).

Differs from Spalacotheridium Cifelli, 1990 , primary trigon by the retention of three distinctive cusps (paracone, cusp B, and cusp C), and a less strongly compressed primary trigon on the upper molars, and by the interruption of the labial cingulid on the lower molars. Differs from Spalacolestes Cifelli and Madsen, 1999 , and Symmetrodontoides Fox, 1976 , by the retention of three distinctive cusps (paracone, cusp B, and cusp C), and a less strongly compressed primary trigon on the upper molars, and by the alignment of the paraconid with the metaconid as well as the interruption of the labial cingulid on the lower molars. Differs from Anebodon Bi, Zheng, Meng, Wang, Robinson, and Davis, 2016 , and Kiyatherium Maschenko, Lopatin, and Voronkevich, 2002 , by more acute angulation of upper molars. Differs from Maotherium Rougier, Ji, and Novacek, 2003a , by more acute triangulation of upper molars and a smaller stylocone and a larger parastyle. Differs from Zhangheotherium Hu, Luo, Li, and Wang, 1997 , by a smaller stylocone and a larger parastyle and presence of a complete lingual cingulum on the upper molars ( Hu et al. 1997; Rougier et al. 2003a; Lopatin et al. 2010; Bi et al. 2016; Plogschties and Martin 2019). Differs from Spalacotherium Owen, 1854 , by a smaller stylocone, a larger parastyle, and a complete lingual cingulum on the upper molars and the interruption of the labial cingulid on the lower molars (labial cingulid interrupted in S. evansae ). Differs from Spalacotheroides Patterson, 1955 , by the presence of a complete lingual cingulum on the upper molars ( Cifelli and Madsen 1999). Differs from Yaverlestes Sweetman, 2008 , by double size and presence of a cingulum on upper molars. Differs from Heishanlestes Hu, Fox, Wang, and Li, 2005 , Lactodens Han and Meng, 2016 (25% smaller), Aliaga Cuenca-Bescós, Canudo, Gasca , Moreno- Leanza, and Cifelli 2004, and Symmetrolestes Tsubamoto and Rougier in Tsubamoto et al., 2004 (half the size) by the interruption of the labial cingulid on lower molars. Differs from Infernolestes Cifelli, Davis, and Sames, 2014 , by a dorsally flexed lingual cingulid and in having the paraconid/ metaconid not closely appressed to the protoconid.

Measurements (in mm).—WMNM P82308, upper molar: length 1.45; width: 1.53. WMNM P82302, upper molar: length: 1.60; width: 1.45. WMNM P82305, lower molar (holotype): length: 1.53; width: 1.00.

Description.— Upper molars: In occlusal view, the primary trigon forms an isosceles triangle with the lingual angle varying from 40° (WMNM P82308) to 54° (WMNM P82302) ( Figs. 3A View Fig 1 View Fig and 4A View Fig 1 View Fig ). This variable angle is dependent on the position of the upper molar along the tooth row, which is known for other spalacotherioids ( Rougier et al. 2003a; Li and Luo 2006; Chen and Luo 2008; Han and Meng 2016). The upper molars have a well developed ectoflexus on the labial side ( Figs. 3A View Fig 1 View Fig and 4A View Fig 1 View Fig ). The crowns of both upper molars are unilaterally hypsodont, being lingually higher than labially as in Akidolestes Li and Luo, 2006 , and are moderately worn. By far the highest cusp is the paracone, separated from the second highest cusp B by a sharp narrow notch on the paracrista ( Fig. 3A 3 View Fig ). Stylocone and cusp C are smaller than cusp B; cusp C is separated from the paracone by a narrow v-shaped notch ( Figs. 3A View Fig 5 View Fig and 4A View Fig 6 View Fig ). The metastylar area is damaged in both upper molars. The paracone is triangular in cross section (occlusal view) with a convex lingual and a flat labial side bearing a low vertical bulge. In WMNM P82302, this bulge extends into the primary trigon basin where it soon fades. Within the trigon basin of WMNM P82302, there is a small, linguo-labially elongated, isolated enamel rising; in WMNM P82308 the primary trigon basin is almost flat and bears only two tiny enamel knots. The paracone is oriented vertically and its apex is worn in both specimens. The small stylocone at the labial end of the paracrista is vertically oriented and bears a small, mesio-distally extended wear facet ( Figs. 3A View Fig 1 View Fig , A 4, 4A View Fig 1 View Fig ). Distally from the deepest point of the ectoflexus is a median cusp which is one third of the size of the stylocone and also bears a small, mesio-distally extended wear facet. The paracrista and metacrista are robust and considerably worn. The parastyle is well developed and hook-like; at the mesial flank it is indented for accommodation of the metastyle of the preceding molariform (upper molar interlock) ( Figs. 3A View Fig 1 View Fig , A 3 View Fig , 4A View Fig 1 View Fig , A 4 View Fig ). The parastyle is worn, and the wear facet along the paracrista is confluent with the wear facet of the parastyle before reaching the stylocone. Like the paracrista, the metacrista is considerably worn and interrupted at the base of the paracone by a narrow v-shaped notch that separates cusp C from the paracone. On the mesial, lingual, and distal sides the crown is surrounded by a sharp, partially crenelated cingulum ( Figs. 3A View Fig 1 View Fig , A 5 View Fig , A 6 View Fig , 4A View Fig 1 View Fig , A 2 View Fig , A 6 View Fig ). Although not preserved completely in any of the specimens, the cingulum is assumed to be uninterrupted based on the almost complementary preservation in both specimens. In WMNM P82302 the mesial part of the cingulum is largely preserved ( Fig. 3A View Fig 1 View Fig , A 3 View Fig ); it rises to the stylocone and bears a groove-like linguo-labially oriented wear facet. The distal flank of the paracone and the distal side of the more labial part of the crown bear shiny wear facets with faint striations oriented about 45° labio-cervically in relation to the occlusal plane. WMNM P82302 shows an additional small wear facet linguocervically of the cingulum (less clear in the holotype specimen). On the mesial flank of the paracone and the mesial sides of the more labial parts of the crown, there are also wear facets detectable with striations oriented 45° labio-cervically, but less clear than on the distal side. The upper molars have two roots, of which in both specimens only the distal root is preserved ( Figs. 3A View Fig 2 View Fig , 4A View Fig 3 View Fig ). The distal root is mesio-distally compressed and straight; a mesio-distal compression can also be assumed for the mesial root according to its preserved base. The lesser degree of mesio-distal compression of the distal root and the longer crown suggest that WMNM P82302 derives from a more anterior position in the tooth row than WMNM P82308.

Right lower molar: The crown in WMNM P82305 (holotype) has the shape of an isosceles triangle and the main cusps of the trigonid are arranged in an angle of about 55° (acute angulation); the lingual side (base line of the triangle) is straight ( Fig. 5A View Fig 1 View Fig ). The lower molar crown is moderately high, somewhat in between Zhangheotherium / Maotherium ( Rougier et al. 2003a; Ji et al. 2009; Plogschties and Martin 2019) and Spalacotherium ( Cifelli and Madsen 1999) . Highest cusp is the protoconid which is slightly bent distally ( Fig. 5A View Fig 3 View Fig , A 5 View Fig ). The protoconid has a triangular cross section with slightly convex mesiolabial and distolabial flanks and a slightly concave lingual flank with a shallow convex bulge running down from the apex into the trigonid basin. Second highest cusp is the metaconid that reaches two thirds of the protoconid height. It has a flat distal flank whereas the lingual, and mesiolingual sides are rounded. It is curved distally and separated from the protoconid by a sharp notch ( Fig. 5A View Fig 1 View Fig , A 3 View Fig , A 4 View Fig ). The apex of the metaconid bears a round wear facet that continues along the metacristid. The paraconid is about half as high as the protoconid and curved mesially ( Fig. 5A View Fig 1 View Fig , A 3 View Fig , A 6 View Fig ). It has a conical shape without pre- and postparacristid. Apically the paraconid bears a drop-shaped wear facet that continues onto the paracristid. The notch between paraconid and protoconid is as deep as that between protoconid and metaconid; it appears less pronounced because the paraconid is more worn than the metaconid. The bases of paraconid and metaconid are confluent with that of the protoconid; the paraconid and the metaconid are clearly separated from each other, resulting in a small, lingually open trigonid basin with lingually sloping floor. The trigonid is surrounded by a marked cingulid which is interrupted above the interradical notch on the labial side ( Fig. 5A View Fig 1 View Fig , A 5 View Fig ). There is a well developed cusp d in the distolingual corner of the tooth crown ( Fig. 5A View Fig 1 View Fig , A 3 View Fig , A 5 View Fig ). It is triangular in shape with flat lingual and rounded mesial side. Its distolabial side is concave for accommodation of cusp e of the succeeding molariform (lower molar interlock). The prominent distal edge of cusp d is crest-like and separates the flat lingual side from the concave accommodation concavity. Its tip bears a small oval wear facet and continues into the crest-like distal portion of the cingulid. The lingual portion of the cingulid is less prominent and merges into the base of cusp d. Mesial cusp e ( Fig. 5A View Fig 1 View Fig , A 3 View Fig , A 5 View Fig , A 6 View Fig ) is about half the size of cusp d and is integrated into the mesial cingulid as a swelling at its lingual end. Its tip bears a drop-shaped wear facet that continues onto the mesial cingulid. The mesial and lingual cingulids are strongly developed and are crenelated. They slope in labial direction and taper out before reaching the interradical notch on the labial side. The lingual cingulid ( Fig. 5A View Fig 3 View Fig ) is somewhat less prominent and also crenelated; it is uninterrupted and rises slightly at the notch between paraconid and metaconid. The roots are slightly curved lingually and the mesial root is somewhat stronger than the distal one ( Fig. 5A View Fig 2 –A View Fig 6 View Fig ). The cross section is triangular for the mesial root and square for the distal root; in the latter the apex is missing. Both roots are concave in the upper part of their inner sides, the mesial root on the distal side and the distal root on the mesial side.