Heterosorex neumayrianus (Schlosser, 1887)

Van Den Hoek Ostende, Lars W., Casanovas-Vilar, Isaac & Furió, Marc, 2020, Stuck in the middle. A geographical appraisal of the oldest insectivores - and a marsupial - from the Vallès-Penedès Basin (early Miocene, Catalonia, Spain), Comptes Rendus Palevol 19 (1), pp. 1-25 : 13-16

Heterosorex neumayrianus (Schlosser, 1887)

( Fig. 5 A-G)

MATERIAL AND MEASUREMENTS (in cm) — Spain. Can Julià , 1 M1 sin., IPS21034 , 1.65 × –; 1 M2 dext., IPS86235 , 1.49 × –; 1 M2 sin., IPS86236 , 1.48 × – ; Can Martí Vell III, 1 i1 dext. fragmented, IPS90036 ; Can Martí Vell II, 1 P4 dext., IPS21023 , 1.52 × 1.45; 1 M1 sin., IPS86257 , 1.60 × 1.86; 1 m 1 dext., IPS86259 , 1.95 × 1.29 ; Can Martí Vell I, 1 Ax sin., IPS86252 , 1.10 × 0.89; 1 maxillary with M1 + M2 dext., IPS21025 , 1.60 × 1.79, 1.38 × 1.71; 1 maxillary with M2 + M3 sin., IPS86241 , 1.45 × 1.82, 0.83 × 1.27; 2 ax dext., IPS86249 -50, 1.26 × 1.01; 1.19 × 0.92; 1 ax sin., IPS86251 , 1.25 × 1.01; 1 i1 sin., IPS86254 ,> 4.75; 1 i1 dext ( IPS86255 ,> 5.06), 2 mandibles with m1-m3 sin. ( IPS86244 -45, 2.08 × 1.30, 1.68 × 1.21, 1.30 × 0.98; 2.15 × 1.18, 1.74 × 1.15, 1.36 × 0.97; 1 mandible with m2, m3 dext., IPS86246 , 1.63 × 1.28, 1.29 × 0.96 ; Cases de la Valenciana 1, 1 M1 dext., IPS86826 , 1.67 × 1.93; ax, IPS86600 , 1.22 × 1.00 ; Costablanca 2, 1 maxillary with M1 + M2 sin., IPS85666 , 1.64 × 1.84; 1.54 × –; 1 M3 sin., IPS85667 , 0.88 × – .

DESCRIPTION

A

The occlusal outline looks like an irregular pentagon. The labial, the posterior and the lingual margins are sub-equal in length, the anterolabial and anterolingual sides being somewhat shorter. The labial margin is parallel to the lingual side, but it occupies a more posterior position. The main cusp occupies an advanced (anterior) position but at similar distance to both lingual and labial sides. A central ridge runs from the anterior tip of the tooth to the central point of the posterior cingulum. The posterior margin is oblique to the central crest and its base is occupied by a cingulum which extends further to both labial and lingual margins. There is a faint connection between the main cusp and the anterolingual corner.

P4

The occlusal outline is not completely triangular because the base of the protocone, at the anterolingual part, protrudes a little bit and makes it more squared. The paracone is the highest cusp and it bears an undulated posterior crest in occlusal view. The posterior margin is rather straight, with no emargination, and covered by a broad cingulum which extends lingually till the protocone. The protocone is only discernible as a small bulge. The hypocone is absent.

M1

The occlusal outline is square. The ectoloph is asymmetric, the anterior part (related to paracone) being shorter than the posterior one (related to the metacone). The mesostyle is only faintly divided. The posterior margin is bordered by a continuous ridge extended from the metastyle to the hypocone. The hypocone is only discernible as a small but sharp elevation in the posterior part of the endoloph. The protocone is placed at the anterolingual corner of the tooth. The anterior arm of the protocone is completely straight in labiolingual direction and connects with the base of the paracone.The posterior arm of the protocone forms the endoloph, running almost parallel to the lingual border, connecting with the hypocone. The metaloph is indicated as a very weak side branch, running towards, the base of the metaconid.

M2

The occlusal outline is less squared than the M1, with a posterior margin shorter than the anterior one. Paradoxically, the ectoloph is more symmetrical than in M1. The mesostyle is also faintly divided. However, this character is already not discernible in specimens with just worn ectoloph. The endoloph is more regular and continuous than in M1. The endoloph is a single element from the base of the paracone which elevates at the protocone and descends regularly with smooth curves down to the hypoconal flange, where it becomes a posterior cingulum ending at the posterolabial corner. There is no evidence of a metaloph connecting the protocone and the base of the metacone.

M3

The occlusal outline is rather triangular, but the posterior corner is rounded. The ectoloph is reduced to a ‘V-shaped’ crest. The mesostyle is divided, so this crest related to the paracone is separated from the posterolingual ‘U-shaped’ crest connecting the protocone and the purported metacone. There is no crest connecting the base of the paracone with the protocone.

i1

The labial and occlusal surfaces connect in an undulated crest with two cuspules.The apex is pointed.The enamel is somewhat wrinkled at the posterior part of the labial face.

a

The occlusal outline is heart-shaped with a slight asymmetry, the labial side being a bit longer than the lingual one.The two lateral (labial and lingual) margins are convex, whereas the posterior face is concave. The main cusp occupies an anterior position. An anterior crest descends abruptly to the anterior tip of the tooth. The two posterior arms connect with the posterolingual and the posterolabial corners respectively, thus delimiting a postero-occlusal concave surface, purportedly for the accommodation of the base of the posterior tooth in a ‘piggy-back’ disposal. In Can Martí Vell I, the specimen IPS86250 is similar in size to IPS86251 but smaller than IPS86249.

m1

The trigonid is longer but narrower than the talonid. The protocone is the highest cusp. The paralophid is straight in occlusal view but concave in labial view, and so is the protolophid. However, the paralophid is longer than the protolophid. The metaconid is a bit lower than the protoconid and it connects with the entocristid by means of a metacristid. Thus, the talonid valley is closed, whereas the trigonid valley is completely open at its lingual side. Entoconid and entostylid are fused, and only a faint notch separating both is discernible. The oblique cristid ends anteriorly at the center of the posterior face of the trigonid. However, the reentrant valley is covered by a labial flange so the basal cingulid is quite straight from the paraconid to the posterolabial corner. There is no cingulid covering the base of the lingual margin of the tooth.

m2

The trigonid and the talonid are similar in both length and width, with a subrectangular occlusal outline. In this case, both paralophid and protolophid are subequal in length.Other than that, the morphological pattern of the m2 follows that of the m1.

m3

The trigonid is much longer and wider than the talonid. Contrary to m1 and m2, the metaconid does not bear a metacristid. Nor is there a well-developed entocristid. The talonid is quite reduced, although it still preserves an inner basin. In the talonid the hypoconid is the only discernible cuspid as such. The basal cingulid covers the labial side of the tooth from the paraconid to the base of the hypoconid.

REMARKS

Jovells-Vaqué et al. (2018) already noted the presence of Heterosorex neumayrianus Schlosser, 1887 in the early Aragonian locality of Las Cases de la Valenciana. As it turns out, this heterosoricid is a quite common element in the early Miocene insectivore faunas of the Vallès-Penedès, particularly in the Aragonian part of the sections.

Whereas the genus Heterosorex is a very common element in central European assemblages ( Doben-Florin 1964; Ziegler & Fahlbusch 1986; Ziegler 1989; Klietmann et al. 2014c), its occurrence in the Iberian Peninsula is far more restricted. It appears near the start of the Ramblian in the localities of Cetina de Aragon ( Van den Hoek Ostende & Furió 2005), Navarrete de Rio ( Adrover 1972, 1975) and Ramblar 1 (Van den Hoek Ostende 2003). It is also present in the Ramblian localities of Alto de Ballester ( Van den Hoek Ostende et al. 2017). In the Aragonian, scattered occurrences have been reported from O’Donell ( Van den Hoek Ostende & Furió 2005), Buñol ( Robles et al. 1991), Mas Antolino ( Agustí et al. 1988),and Montalvos 2( Hordijk et al. 2015). The most notable occurrences, however, are in the Daroca Calamocha area, where Heterosorex appears in a series of localities as a transient species during zone C ( Van der Meulen et al. 2012; Van den Hoek Ostende et al. 2016). Most finds from the Vallès-Penedès coincide with this interval, so they could be part of the same ‘ Heterosorex -event’. However, even with the limited record we have, the genus is also found in the Ramblian site of Costablanca 2. Therefore, also considering the occurrences in Buñol and Mas Antolino, it seems more plausible that the heterosoricids found more suitable habitats in the coastal region and only ventured inland during optimal conditions.