1
Electronic suppl. material 1
Section 1: complete description
Precise illustration of the auditory region is provided through the other electronic supplementary file: ESM2_auditory_region_Kuntinaru.tif
TEETH
MNHN-SAL 1024 and MNHN-SAL 3 are incomplete rostrally.
On MNHN-SAL 1024, only the most lateral part of the left side is preserved but the tooth row is heavily damaged. 7 tooth sections are preserved. The most anterior one only preserves a section close to the base of their crown. It only consists in a minute cylindrical section situated very close to the skull roof. This most rostral preserved tooth is smaller than the second one (despite the bias on the height of the sections).
The third and fourth most anterior teeth are sectioned closer to their original occlusal surface (close to the palate level). The three posterior teeth are deeply abraded or exhibit several artefactual breaks.
The central teeth in this raw is the largest ones, the three most posterior teeth showing undoubtedly a posteriorly decreasing size gradient, with the last tooth being the only one to present a circular rather than an ovale section.
Only two teeth, in the middle of the tooth row on MNHN-SAL 3, exhibit an undamaged occlusal surface, providing informations on the tooth wear: the dental surface is beveled anteroposteriorly.
SKULL:
NASAL-FACIAL REGION
Most is lacking. The nasals are not preserved. The sutura maxillary-frontal is long and oblique between the orbits and the nasals, being more similar to Euphractus than to Dasypus whose sutura is curved. The posterior part of the nasals is narrow and not penetrated by a deep median anterior projection of the frontals. At least, two additional openings transmitting nutrient veins open in front of the infraorbital foramen (Wible and Gaudin, 2004).
The infra-orbital foramen is situated high above the level of the tooth row (or the palate). It is located clearly higher relative to Dasypus or Euphractus. Tolypeutes exhibits a closer condition.
The anterior root of the zygomatic arch seems to arise from the level of the 5th preserved tooth (the 3rd most posterior).
The facial outline of the lacrimal is triangular. As usual in armadillos, the mx-fr suture meets the lacrimal at the level of the anterior angle of the triangle defined by its dorsal exposure.
The frontal dorsal surface shows a pentagonal shape that is widest in the middle of its anteroposterior extension. It is sloping anteriorly, with no relief but two lateral swellings (bulges) in the middle of its anteroposterior extension at the level of the anterior root of the zygomatic arch. These bulges are well domed. Most armadillos, with the noticeable exception of Dasypus, often present this feature (it is remarkably developed as two huge transverse crests in Chlamyphorus).
Kuntinaru presents an important post-orbital constriction well extended anteroposteriorly. There is no marked postorbital apophysis. The frontal-parietal suture is well posterior to the postorbital constriction.
PALATE
Only the posterior part of the palate can be described, mostly from MNHN-SAL 3. The tooth rows are strictly parallel and close to each other.
The suture of the palatine/maxillary extends anteriorly as far as the anterior part of the antepenultimate tooth on MNHN-SAL 3. This suture course passes very close to the two last teeth and almost contacts them lingually. Then, it runs slightly away from the 3rd most posterior tooth and turn medially when at the level of the anterior part of this tooth. It is undulating, like a M, when the observer looks the palate from a posterior perspective. Backward to the most posterior tooth, the course of this suture is not clearly distinct on the 2 specimens.
The pterygoids are not preserved. The space between the last tooth and the choanae is small.
The posterior midline part of the palate bears a crest on the median palatine suture. A paired small foramen is preserved just ahead of the mx-pal suture, and may be the major palatine foramen. A tiny foramen is present, on both sides, medioposterior to the most posterior tooth, only separated from it by the mx-pal suture. This foramen might correspond to the minor palatine foramen. It may be a fickle feature as it is only present on the left side of MNHN-SAL 3. The posterior margin of the palate forms a semi-ellipse in ventral view. Its most anterior point reaches the level of the posterior part of the most posterior tooth
ORBITOTEMPORAL REGION AND SKULL ROOF:
The maxillary foramen, i.e. the orbital opening of the infraorbital canal, opens in the orbital cavity like in most armadillos. Conversely, in Cabassous and Priodontes, this foramen opens outside the orbital cavity, clearly below the ventral edge of the anterior root of the zygomatic arch.
The maxillary occupies most or all of the lower half of the orbital cavity whereas the frontal does so for the upper part. The lacrimal orbital extent is not clear but is obviously reduced.The lacrimal foramen may have lied just on the edge of the orbit, but this part is slightly damaged.
The frontal-maxillary suture slopes posteriorly. The suture maxillary-palatine is not discernible.
There is a small foramen posterior to the maxillary one, at the level of the most posterior point of the anterior root of the zygomatic arch, probably an accessory foramen like those present in Euphractus between the maxillary foramen and the caudal palatine foramen (Wible & Gaudin 2004, fig. 3B).
Like all xenarthrans, the specimen does not present a true maxillary floor in the orbit but only a large vertical medial orbital wall.
The skull MNHN-SAL 1024 exhibits a large break at the level of the postorbital apophysis. This precludes the observation of the ethmoid foramen and of the anterior suture of the orbitosphenoid.
The anterior foramen of the orbitotemporal canal opens dorsal to the course of the frontal-alisphenoid suture. It is not reduced and forward directed. The sphenorbital fissure opens at the same level but much more ventrally. The suture orbitosphenoid-alisphenoid passes within the sphenorbital fissure. Slightly more anterior within the orbitosphenoid bone opens the optic foramen. Its opening is smaller than that of the sphenorbital fissure. It is tricky here to delineate the presence of another foramen ventral to these, as described in Euphractus (rostral opening of the pterygoid canal; Wible & Gaudin, 2004), because this region suffered a significant flattening.
The orbitosphenoid extent is higher than longer. The extent of the palatine bone in this region cannot be precised. The alisphenoid wing has a wide quadrangular extent. The dorsal course of its suture slopes slightly anteriorly, whereas the anterior and posterior courses are parallel and grossly vertical. The ventral course is not distinct, but obviously runs anteroventral to the sphenorbital fissure.
From a lateral perspective, the dorsal outline of the posterior root of the zygomatic arch is roughly horizontal and sinuous, like Tolypeutes and Prozaedyus. In this respect, it strongly differs from Dasypus, Cabassous, Priodontes, and Chlamyphorus whose corresponding region presents a sharp break slope, as well as from Euphractus, Zaedyus, and Chaetophractus which display a straight and oblique outline. A horizontal crest runs from the medial edge of the posterior root of the zygomatic arch, called the orbital muscular crest by Gaudin & Wible (2006). This crest crosses the squamosal-alisphenoid and the alisphenoid-frontal sutures, and ends forwards to the posterior edge of the anterior opening of the orbitotemporal canal.
From a lateral perspective, the squamosal displays a triangular outline, with an angle pointing anteriorly. The most anterior point of this angle goes slightly forward the level of the frontal-parietal suture. The squamosal contacts the frontal over this point and thus prevents an alisphenoid-parietal contact. The parietals occupy a large surface on the skull roof. This surface is domed.
The temporal lines do not meet in the midline. They are very slightly converging posteriorly but still distant from the midline.
The posterior part of the posterior root of the zygomatic arch exhibits a triangular depressed area in which open two foramina. The larger one, the suprameatal foramen, opens anteroventrally at the bottom of a trough directed towards the posteromedial direction. The other foramen opens at the bottom of a small circular pit directed anteromedially or medially (it varies on the two sides of a same skull). This is very different from Dasypus whose two seemingly homologous foramina are much more distant from each other.
In its most ventral part, the parietal is crossed by multiple foramina that are minute in the most anterior part of the bone, and then more deeply marked (with a gutter) posteriorly. The nuchal crest and the dorsal edge of the posterior root of the zygomatic arch do not constitute a continuous relief.
From a lateral perspective, the skull roof has a sinuous outline in its posterior half. It is domed posterior to the postorbital constriction, and then depressed in the most posterior part. Anterior to the postorbital constriction, the skull roof bearsa pair of lateral bulges and slopes forward.
BASICRANIUM AND AUDITORY REGION
Like in all armadillos, the occipital condyles are massive.
Contrary to Dasypus, the outline shape of the auditory region (from the level of the foramen ovale anteriorly) is much wider than longer, but not to the extent observed in extant euphractines.
The foramen ovale opens at the level of the anterior edge of the posterior root of the zygomatic arch. In the same depression, a small bridge delimitates the transverse canal foramen (see Wible & Gaudin, 2004) from the foramen ovalein MNHN-SAL 3. This bony bridge is tiny and has not been preserved in MNHN-SAL 1024.
The foramen ovale is bordered posteriorly by a thick crest running continuously and obliquely from the entopterygoid crest to the dorsal edge of the auditory porus. This crest really defines a strong separation of the petrosal from the anterolateral adjacent structures. This crest is less developed in other armadillos and often shows a break slope at the level of the alisphenoid-squamosal suture. This massive and continuous crest may be a character unique to Kuntinaru. This crest shows an equivalent contribution of the alisphenoid anteromedially and of the squamosal posterolaterally. The suture alisphenoid/squamosal crosses perpendicularly this crest at its midpoint.
There is no true glenoid fossa, just a surface somewhat flattened and bordered medially by the above-mentioned crest. It even slightly slopes laterally towards the dorsal direction.
Posterior to this surface, just dorsolateral to the dorsal edge of the auditory porus opens the postglenoid foramen. It is laterally bordered by a crest. This crest runs from the posteroventral extremity of the dorsal edge of the auditory porus and tapers off towards a more dorsal point on the posterolateral edge of the posterior root of the zygomatic arch. Such a crest is absent in Dasypus for which the location of this foramen is much anterior to the tympanic notch. It is present in Tolypeutes, tiny in Cabassous, and absent in Priodontes; unfortunately, its presence cannot be checked in the taxa with an ossified bulla, such as the extant euphractines.
The squamosal contributes to the entire dorsal edge of the auditory porus. As no tympanic bone is preserved, there is no more information on the porus. Medial to this notch, the squamosal also participates in the lateral half of a shallow depression (the petrosal defines the medial half): this depression is the epitympanic recess. It is wider and much shallower in Kuntinaru than in Dasypus, and more similar to Priodontes and Tolypeutes.An epitympanic recess is lacking in Euphractus (Wible and Gaudin, 2004): the roof of the recess has been lost and then provided space for an epitympanic sinus.Posterior to the epitympanic recess, the squamosal is restricted to a thin and short lamina on the lateral edge of the skull. This part constitutes the post-tympanic process of the squamosal, which lies against the larger paroccipital process of the petrosal (Wible, 2010; Wible & Gaudin, 2004).
The roof of the choanae is flat; no suture is discernible on it. The basisphenoid-basioccipital suture is not really well-marked. In Kuntinaru, there is only some kind of transversal rugosity that may be the mark of it. It is situated at the level of the anterior edge of the petrosal/piriform fenestra.
Almost all along its midline, the basioccipital bears a well marked medial crest; its development reduces posteriorly close to the foramen magnum.
Posterior to the longus colli tubercles, the medial floor of the skull enlarges. The large hypoglossal foramina open just dorso-anterior to the occipital condyles. The dorsal edge of the hypoglossal foramen is formed by a bony bridge (basioccipital) which shows a dorso-ventral discontinuity with the main (basioccipital) basicranium medial floor. This bridge contacts the medial edge of the petrosal at its posterior third and then projects somewhat dorsally and parallels the petrosal medial edge on all its length.
The ventral edge of the foramen magnum displays a sharp V outline pointing forward (the extremity of V corresponds tothe odontoid notch). The exact outline of the occipital condyles is difficult to sort out but their main axis is slightly oblique relative to the transverse direction.
The occipital condyles of Kuntinaru exhibit a deep notch on their medial edge, ventral to the cranial aperture of the hypoglossal foramen. A fossa is also present on the medial edge of the condyles in Euphractus, Chaetophractus, Zaedyus, Chlamyphorus, Priodontes, Cabassous, and Tolypeutes. A prolongation of this fossa often defines a medial notch in the ventral surface of the condyles. Such a notch and/or fossa is absent in Dasypus, Bradypus, and Tamandua. In addition to the medial notch, Kuntinaru presents like most armadillos a notch in the lateral edge of the occipital condyles.
From the antero-medial corner of the large fossa housing the petrosal, a tiny groove runs towards the medial edge of the entopterygoid crests. This should be the groove for the auditory (Eustachian) tube.
The jugular foramen (posterior lacerate foramen) opens posteromedial to the sharp notch exhibited by the petrosal at its posteromedial corner (see below).
Lateral to the occipital condyles is a broken process, whose dorsal basis shows an anteroposterior orientation. This is the paroccipital process of the exoccipital of uncertain development.
Kuntinaru does not preserve any part of the tympanic bones and as such might have presentedno well-ossified bulla and not well-fused ento- and ecto-tympanic. This would resemble to the dasypodines and extant tolypeutines (and possibly also the glyptodontids) who present no broad fusion of their ento- and ectotympanic.
PETROSAL
Only the tympanic face and the mastoid exposure of the petrosal are observable.
The tympanic face of the petrosal of Kuntinaru displays a large flattened surface extending ahead of the inflated promontorium, the epitympanic wing. In Kuntinaru, Tolypeutes, Cabassous, Proeutatus, and Propalaeohoplophorus, the promontory and epitympanic wing are elongated in the anteromedial direction only, and go far anterior past the tegmen tympani. In the extant euphractines and Priodontes, the promontory and epitympanic wing spread anterolaterally as much as anteromedially and do not go anterior past the level of the tegmen tympani. In Dasypus, the extent of the epitympanic wing is very weak (Wible, 2010: fig. 5).
Antero-medially, the petrosal contacts the alisphenoid and as a consequence there is no piriform fenestra at this location. Such a fenestra may lay a little more posterolaterally but the breakages and the dislocations in both MNHN-SAL 3 and 1024 preclude this assertion.
The part housing the hiatus fallopii is missing but a large part of the roof between the promontorium and the crista parotica ispreserved. The secondary facial foramen opens just slightly anteriorly (and lateral) to the fenestra vestibuli. The crista parotica is high, long and oriented strictly anteroposteriorly. The crista parotica runs very close to the vestibular fenestra of the promontorium (possibly typical of all xenarthrans).
The part lateral to the crista parotica defines, with the squamosal, the epitympanic recess just described above. Posteromedial in this depression, a small pocket(i.e. the fossa incudis) can be identified. It is situated slightly posterior to a transverse virtual line connecting the fenestra vestibuli to the postglenoid foramen. Anterior to the epitympanic recess, a clublike ventral process is in continuity with this latter, just lateral to the anterior part of the crista parotica. Its ventral tip is slightly concave. This is the tegmen tympanii as defined in Wible (2010) for Dasypus.
The fenestra vestibuli is weakly elongated anteroposteriorly. It faces laterally. The fenestra cochleaeis posteroventromedial to the preceding, like usual in eutherians, and clearly larger. Its outline looks like a half ellipse with the linear basis being dorsal. It is bordered ventromedially by a thick process that curves laterally just slightly posterior to it. This process constitutes a postero(medial) outgrowth on the tympanic face of the petrosal, and defines a sharp notch with the more medial part of the petrosal. This notch houses more dorsally the cochlear canaliculus, like in Dasypus (Wible, 2010).