A Pleistocene Fight Club revealed by the palaeobiological study of the Dama-like deer record from Pantalla (Italy)

Here, we report on the exceptionally well-preserved deer record from the locality of Pantalla (central Italy), dated in the Early Pleistocene (ca. 2.1–2.0 million years ago). The fossils show a combination of characters that allows an unambiguous attribution to ‘Pseudodama’ nestii, of which they represent one of the most informative collections to date. Our comparisons—also conducted through CT-based methods on endocranial structures—reveal that the cranial and postcranial skeleton of ‘P.’ nestii displays a mosaic of intermediate characters between extant Dama and Cervus, but also that the affinities with Dama are prevalent. Some Cervus-like features especially in cranial morphology, can be interpreted as plesiomorphic characters supporting a basal position of ‘Pseudodama’ among the Cervini. Interestingly, three bone anomalies are described in the two male crania of ‘P.’ nestii from Pantalla and are interpreted as palaeotraumatological evidence resulting from different injuries suffered by the deer during their life. This allows opening a treasure trove of information on paleobiological aspects, including ontogeny and antler cycle and function.

third valley is shaped as a very shallow incision not visible along the lingual wall. The distal part of p4 is wide mainly due to the development of a massive hypoconid. Lower premolars do not show cingula in any specimen. Conversely, a strong mesiobuccal cingulum is present in all lower molars. These latter also show well-developed but low ectostylids between mesial and distal lobes and, in m3, also between distal lobe and hypoconulid. In little worn molars, a V-shaped opening on the lingual side between entostylid and posterior hypoconid wing is present. In 337631 ( Supplementary Fig. S1g), although left and right i1 are displaced by diagenesis, the teeth forming the incisor arcade are arranged along a wide arch. The labial wall of i1 is markedly bent outwards. As for deciduous teeth (Supplementary Figs S1c and S1f), dp2 is a short and narrow tooth, with sub-triangular occlusal outline; it mimics the general morphology of p2 but has a shallower second valley. On the contrary, dp3 is relatively long and narrow, with poorly developed first valley and deep second valley. The dp4 is formed by three similar-sized lobes, between which low and pointed ectostylids rise up, similar to those observed in permanent molars.
In the axis, only the anterior portion of the spinous process is preserved and it projects cranially (as in D. dama, Char. 4 39 ), but not further than the dens. Both transverse processes are destroyed along with the left side of the anterior articular facet and both postzygapophyses. The left portion of the body is also damaged. Of the cranial transverse foramen, only the dorsal opening is visible as it is fused with the intervertebral foramen. The dens protrudes more than the articular facet with whom it produces a right angle. On the right side, the vertebral body is mostly intact along with the rim of the cranial articular facet and the ventral crest. In anterior view, the dens is damaged on the right margin, but otherwise once formed a single, crescent-shaped articular facet. The neural arch is entirely filled with sediment.
The cervical vertebra III (better preserved than the IV) presents a tear-drop-shaped cranial articular surface that is convex and widest at its dorsal margin. The spinous process is missing, along with most of the transverse processes and tubercles. In dorsal view, the left prezygapophysis is intact. The ventral tubercle of the left transverse process is also partially present. The two postzygapophyses are damaged, but their general outline is still recognizable. In caudal view, the caudal articular surface is concave and mostly broken. Dorsally, the neural arch delimits a large canal, which is narrower at its ventral margin. On either side, the transverse foramina are less noticeable than on the cranial margin.

Metacarpal
Specimen 337652 ( Supplementary Fig. S2b) is a right metacarpal missing the distal portion.
The section of the diaphysis is D-shaped. The dorsal surface is strongly convex whereas the lateral and medial surfaces are flatter. The tuberosity at the proximomedial corner of the anterior surface is not rough (as in D. dama, Char. 5 39 ). The palmar surface is characterized by a central groove -mostly destroyed. A clearly-defined mild pit is visible at the proximomedial corner of the palmar surface (as in D. dama, Char. 4 39 ). The proximal epiphysis is intact. The articular surface is trapezoidal in outline -the dorsal margin is rounded whereas the medial and palmar margins are straighter. The articular surface is smooth. The medial articular facet is larger than the lateral one, and the two are joined palmarly (as in D. dama, Char. 1 39 ). They surround a large nutrient foramen, which is oval in shape and located just before the palmar margin. The medial articular facet is subrectangular, with rounded edges. Contrarily, the lateral articular facet is subtriangular.

Hindlimb
Specimen 167353 is a right partial articulated hindlimb composed of a distal tibia, astragalus, incomplete calcaneum, lateral malleolus, cubo-navicular, cuneiforms, metatarsal with medial phalanx I and sesamoids attached by sediment, lateral phalanges I and II, and lateral sesamoids ( Supplementary Fig. S2d-m). The medial phalanx II 167357 is almost certainly part of the same limb.
The tibia ( Supplementary Fig. S2d) is broken approximately half way up the shaft, thus missing the proximal portion whereas the distal epiphysis is intact. The diaphysis, where preserved, presents an oval section -dorsoplantarly compressed. In dorsal view, the shaft is slightly concave and flat, just above the epiphysis. Plantarly it is convex. The medial malleolus is slender and extends below the central spine -it also presents a small articular facet on its lateral surface. In distal view, the articular surface is intact and well preserved -having been fossilized articulated with the other elements of the ankle. Both the articular grooves are visible; the medial one is more mediolaterally compressed and presents narrow dorsal and plantar margins. The lateral articular groove is more rounded in outline and is separated from the medial groove by a prominent ridge. They are both parallel to the longitudinal axis of the shaft. On the lateral margin of the articulation, there are two small articular surfaces -slightly concave and rounded in shape. The dorsal articular facet is smaller, downturned plantarly (as in D. dama, Char. 4 39 ), and separated from the plantar facet by a deep V-shaped groove. Dorsally to the dorsal articular facet a small flat shelf develops (as in D. dama, Char. 3 39 ). In medial view, the medial malleolus appears oriented dorsally, describing a wide U-shaped dorsal margin (as in D. dama, Char. 5 39 ). Plantarly to the medial malleolus there is a groove that extends up the shaft, parallel to it. This groove is also visible in plantar view.
The astragalus ( Supplementary Fig. S2i) is well preserved. In dorsal view, the proximolateral condyle protrudes more than the medial one. The central portion forms a flat-bottomed U-shape (as in D. dama, Chars. 1-2 39 ). The lateral projection of the lateral condyle has a vertical margin (as in D. dama, Char. 4 39 ). The lateral bulge between the proximal and distal half of the astragalus is pointed and projects laterally in dorsal view (as in C. elaphus, Char. 5 39 ). Both trochlear condyles are parallel to the sagittal plane and the surface in between is strongly concave. Plantarly, the articular facet for the calcaneum is proximo-distally convex and occupies most of the plantar surface. Proximo-laterally to the facet, the ridge of the lateral condyle is triangular in shape and pointed, with a rounded furrow on its lateral surface. On the distal portion, there are two small oval depressions, which respectively articulate with the medial and central proximal projections of the cubo-navicular. In medial view, the distal condyle is rounded. The dorsomedial corner of the medial surface strongly projects dorsally (as in D. dama, Char. 3 39 ). The proximal portion presents a well-defined furrow along its dorsal margin -where the medial malleolus articulated -on its plantar margin it ends in a pointed protuberance. The remaining medial surface appears rough. In lateral view, the distal border of the lateral condyle is slightly convex and corresponds to the calcaneum articular facet. The space in between the two is irregular.
The calcaneum ( Supplementary Fig. S2j) misses almost all the dorsal process, as only the articular facet to the lateral malleolus and part of the plantar articular facet for the cubonavicular are preserved. In distal view, the main articular surface is squared in outline, with rounded dorsal and medial margins. The body of the calcaneum is intact. The proximal portion of the body is elongated, medio-laterally compressed, and presents an irregular, enlarged tuber calcanei. The trochlear facet -a rounded projection that articulates to the lateroplantar margin of the astragalus -and the plantar margin of the main articular surface are visible. Medially, the trochlear facet appears semi-circular in outline. It is connected to the main articular facet by a small, concave articular surface. The tuber calcanei in medial view presents a furrow, that separates the plantar portion and the dorsally pointed portion. The dorsal and plantar borders are straight and parallel to the proximodistal axis. The sustentaculum tali protrudes medially and the plantar end is inclined distally. It has an oval outline and does not protrude beyond the plantar margin of the main body -between the two there is a deep groove. The scar on the plantar surface extends further than the dorsal edge of the sustentaculum tali (as in D. dama, Char. 1 39 ).
The cubo-navicular ( Supplementary Fig. S2k) is almost perfectly preserved, a portion of the dorsal medial margin is broken and there is sediment adhering to the articular surfaces and to the plantar margin. In proximal view, the articular surface has two grooves parallel to the sagittal plane. Plantarly to each groove, there is a pointed projection -the medial one larger than the lateral one. On the lateral margin, there is an elongated, convex articular surface that articulated with the dorsal process of the calcaneum. Distally, the four articular facets are intact. The general outline is that of a quadrilateral with rounded edges and the dorsal articular facets are larger than the plantar ones. The larger, dorsolateral facet for the metatarsal is separated from the others by an L-shaped non-articular surface. At the junction, there is a small pit. The small, plantar articular facet for the metatarsal is orientated mediolaterally and has an elongated shape. The medioplantar facet for the small cuneiform is bean shaped. In plantar view, the medial and lateral projections are most noticeable. The furrow separating them is also visible and is V-shaped with rounded margins. The lateral projection of the calcaneum facet is lower than the medial projection. Laterally to the groove there is a large foramen almost directly in the centre of the plantar wall. The overall outline is rectangular.
The large cuneiform ( Supplementary Fig. S2g) is proximo-distally compressed. The proximal surface is concave, while the distal one is convex. The plantodistal margin is narrow and pointed. The small cuneiform ( Supplementary Fig. S2g) is rounded and drop shaped. It also is proximo-distally compressed.
The lateral malleolus (i.e., the vestigial distal portion of the fibula - Supplementary Fig.  S2f) is irregular in shape. Proximally it articulates to the tibia, medially to the astragalus, and distally to the calcaneum.
The metatarsal ( Supplementary Fig. S2e) is quite well preserved -two sesamoid bones and the medial phalanx I are still articulated, attached by sediment. The diaphysis is broken in numerous places, causing the distal epiphysis to bend medially. The diaphysis is damaged mainly in the central part, where the walls of the shaft are mediolaterally compressed along the mid-line groove and have crashed into the medullary cavity. The phalanx leans ventrally. The proximal epiphysis is rectangular in outline and the nutrient foramen is visible. The four articular facets are smooth; the dorsal two are concave whereas the plantar two are coated in sediment. The dorsomedial and dorsolateral facets join each other dorsally (as in D. dama, Char. 1 39 ) and lie on the same level (i.e., there is not a step between the two (as in D. dama, Char. 2 39 ). The distal epiphysis is coated in sediment and -in lateral view -leans slightly ventrally. In plantar view, the two sesamoid bones are still in anatomical position, on the plantar surface of the medial trochlear condyle. Looking at the proximal edge of the intertrochlear groove in plantar view, no split is visible (as in D. dama, Char. 5 39 ). The overall morphology of the right metatarsal 337651 ( Supplementary Fig. S2c) is very similar to that of 167353, although the state of preservation of the proximal articular surface is quite poor in the former.
The medial phalanx I of 167353 ( Supplementary Fig. S2e) is still articulated to the medial condyle of the metatarsal, while the lateral phalanx I is disarticulated. These phalanges are almost complete, with the exception of the proximo-lateral edge of the medial one. In proximal view, there is not a step-like projection of the groove between the articular facets (as in D. dama, Char. 1 39 ). In the lateral phalanx, the medial metapodial facet is somewhat more dorsoplantarly extended than the lateral metapodial facet. The latter also protrudes more with respect to the medial facet. On the plantar margin of the articular surfaces, there are two rounded sesamoid facets. The plantar end is rectangular, in outline, with rounded edges.