Brachypotherium brachypus (Lartet, 1851)

Koufos, George D. & Kostopoulos, Dimitris S., 2013, First report of Brachypotherium Roger, 1904 (Rhinocerotidae, Mammalia) in the Middle Miocene of Greece, Geodiversitas 35 (3), pp. 629-641 : 634-638

publication ID	https://doi.org/ 10.5252/g2013n3a6
persistent identifier	https://treatment.plazi.org/id/03F07C25-3B1F-FFCF-AEDD-D857FE2E00CD
treatment provided by	Marcus
scientific name	Brachypotherium brachypus (Lartet, 1851)
status

Treatment

TYPE LOCALITY. — Sansan, France, Early Astaracian, MN 6.

LOCALITY. — Chryssavgi, CHR, Macedonia, Greece ( Fig. 1 View FIG ).

AGE. — Late Astaracian, MN 7+8 (Middle Miocene)

MATERIAL. — Right M3, CHR-500; fragment of a left M1,2, CHR-501; left mandibular fragment with m2- m3, CHR-502.

MEASUREMENTS

M3: L = 52.1, B = 60.8;

m2: L = 52.3, Bant = 32.5, Bpost = 32.2;

m3: L = 54.0, Bant = 31.3, Bpost = 29.5.

DESCRIPTION

M3 ( Fig. 3 View FIG D-F)

It is worn with triangular occlusal outline and thick enamel; a relatively shallow parastyle furrow separates the paracone from the parastyle; large protoloph almost perpendicular to the lingual margin of the tooth; large protocone with deep mesial and distal protoconal furrow; elongated and narrow ectometaloph with slightly convex profile; presence of crochet and antecrochet; absence of crista; deep and open lingually medisinus with strong cingulum; strong mesial cingulum in the lingual half of the tooth; strong distal cingulum in the base of the hypocone.

M1-2 ( Fig. 3 View FIG A-C)

Although CHR-501is referred by Dimopoulos (1972) it is not described; it is worn lacking its mesial part. The preserved part of the ectoloph is flattened and bears a distinct cingulum; presence of crochet and antecrochet; absence of crista; well developed distal hypoconal furrow; narrow and open lingually medisinus with cingulum in its entrance; large hypocone; the post-fossette is restricted to a small pit, closed distally by the strong distal cingulum.

m2-m3 ( Fig. 4 A-C)

The teeth are worn with similar length and thick enamel; shallow buccal groove distinguishing the two lobes; small paralophid extending lingually at about the middle of the trigonid’s breadth; angular hypolophid extending lingually more than the metalophid; small, narrow and V-shaped trigonid valley; its mesial border consists of a weak cingulum running disto-lingually from the paralophid’s top to the tooth base; large, deep, U-shaped and open lingually talonid valley; clear buccal cingulum in the mesial lobe descending from the top of the paracone to the base of the protoconid; weak distal cingulum.

D ISCUSSION

The mandibular fragment CHR-502 was described as Diceros pachygnathus by Psarianos (1958: 306,

abb. 1) and considered different from Brachypotherium brachypus because of its smaller dimensions, absence of buccal cingulum and enamel morphology without, however, more explanations for the last character. Later, the mandibular fragment CHR-502 and some other upper teeth from CHR were attributed to Dicerorhinus orientalis ( Dimopoulos 1972) . The CHR material is mentioned as Rhinocerotidae indet. in the review of the large mammal succession of Greece, as well as in that of the Miocene rhinoceroses of Greece ( Bonis & Koufos 1999; Giaourtsakis 2003). In the revision of the Neogene mammal faunas of Greece the CHR rhinocerotid is reported for first time as Brachypotherium sp. ( Koufos 2006) .

Both previous studies of the CHR rhinocerotid imply a Late Miocene age ( Psarianos 1958; Dimopoulos 1972). Two main rhinos are known from the Late Miocene of Greece “ Diceros ” neumayri (Osborn, 1900) often called Ceratotherium neumayri or Diceros pachygnathus and Dihoplus pikermiensis (Toula, 1906) ; the former species is the most common. A direct comparison of the studied material with that of “ Diceros ” neumayri from Axios Valley ( Macedonia, Greece) suggests that the latter species differs from the CHR sample, having more buccally projected parastyle in the M3, absence of distal hypoconal furrow, deeper buccal groove in the lower molars, longer paralophid, absence of cingulum in the lower teeth and more hypsodont teeth. Based on the dental description and illustrations of Giaourtsakis et al. (2006) and Geraads & Spassov (2009) for Dihoplus pikermiensis it differs from the CHR material, having somewhat smaller dental size, less flattened ectoloph, a trend for separation of the protocone from the protoloph, weaker or absent cingulum in the medisinus of the M3, longer paralophid, lower molars with well developed buccal groove which continues down to the crown basis and absence of cingulum and cement. Therefore both older determinations must be abandoned.

According to Guérin (1980: 202) the genus Brachypotherium is characterized by large teeth, brachyodont cheek teeth (especially the upper ones) and strong buccal cingulum in the upper cheek teeth. Heissig (1972: 79) refers that the molars of Brachypotherium are brachyodont with strong cingula in the upper and weak buccal groove in the lower ones. Geraads & Spassov (2009: 110) mention the brachyodont molars, the absence of crista, the weak crochet and antecrochet, as well as the slightly pinched protocone and hypocone in the molars for Brachypotherium . The studied teeth have similar characters and can be referred to this genus.

Brachypotherium is well known from the Miocene of Central and Western Europe, by two species B. brachypus (Lartet 1851) and B. goldfussi (Kaup, 1834) ; the previous taxon includes the Middle Miocene and the latter one the Late Miocene brachypotheres ( Cerdeño 1993; Cerdeño & Nieto 1995; Antoine et al. 1997, 2000). The distinction of the two species is difficult as their differences are not clear ( Guérin 1980). The dental proportions, brachyodonty, frequency of the buccal cingulum and the virtual absence of the buccal groove of the lower teeth distinguish B. goldfussi from B. brachypus ( Guérin 1980) . The studied lower molars are characterized by a weak but clear buccal groove, a mesio-lingual cingulum and a well developed mesio-buccal one, as well as different proportions from B. goldfussi . The m2 and m3 of B. brachypus seem to be more robust than those of B. goldfussi . The index L × 100/B is at mean 62.2 versus 59.1 for the m2 and 56.3 versus 50.5 for the m 3 in B. brachypus and B. goldfussi respectively (the dental measurements of the two species are taken from Cerdeño [1993] and Guérin [1980]). In the CHR-502 teeth this index is 62.3 and 58.5 respectively, being closer to those of B. brachypus (for the calculation of the index the large anterior breadth is taken, when it is given). B. brachypus is well-known from Western Europe ( Ginsburg & Bulot 1984; Cerdeño 1993; Cerdeño & Nieto 1995; Antoine et al. 1997, 2000; Ginsburg 2001). Roman & Viret (1934), describing the material from the French locality La Romieu, mentioned the presence of a remarkable lingual cingulum, a well developed crochet and antecrochet and absence of the crista in the upper molars, as well as the absence of buccal groove and a well developed buccal cingulum in the lower teeth; all these characters are present in the studied teeth. Likely the CHR dental morphology fits well with the Bezian material of B. brachypus ( Ginsburg & Bulot 1984: 359, pl. III, figs 2-5). In the revision of the Middle Miocene French brachypotheres Cerdeño (1993) mentioned that the upper molars of B. brachypus have well developed crochet, variable size or absence of crista and elongated ectometaloph in the M3. The CHR teeth fit morphologically with the French B. brachypus having similar dimensions ( Fig. 5 View FIG ).

In the Eastern Mediterranean B. brachypus is known mainly from Turkey. Its presence is

A originally mentioned by Heissig (1976), who described some material (mainly isolated teeth) from various Middle Miocene localities. Based on the descriptions and figures of Heissig (1976), the CHR material is morphologically and metrically ( Fig. 5 View FIG ) similar to that from Turkey. The species is also reported by some isolated teeth from Paşalar ( Fortelius 1990); they are morphologically and metrically ( Fig. 5 View FIG ) similar to the studied material. Some postcranials of B. cf. brachypus are also mentioned from the locality of Çandır ( Geraads & Saraç 2003). Except these Middle Miocene occurrences, Brachypotherium is also reported from the Late Miocene of Bulgaria. The anterior part of a skull from Ahmatovo and a juvenile skull from Kalimantsi are referred to this genus ( Geraads & Spassov 2009). The Ahmatovo teeth differ from the studied ones having slightly pinched protocone and hypocone in the molars, weaker crochet and antecrochet, absence of crista and reduced cingula ( Geraads & Spassov 2009). The authors mentioned the similarities of the Ahmatovo skull with the African brachypotheres and B. perimense (Falconer & Cautley, 1847) from Siwaliks, contrary to the European material of the genus.

Two brachypotheres are known from the Middle Miocene of Siwaliks, Pakistan: B. perimense (Falconer & Cautley 1847) and B. fatehjangense (Pilgrim, 1910) . Based on the descriptions of Colbert (1935) and Heissig (1972) B. perimense differs from CHR in the less pinched protocone, the deeper parastyle in the M3, the deeper buccal groove in the lower molars, the narrower lower teeth ( Fig. 5 View FIG ) and the relatively more hypsodont teeth. The other Siwaliks brachypothere B. fatehjangense is considered as being very close to B. brachypus ( Antoine et al. 2000) , but Khan et al. (2010) separate it from B. brachypus by the presence of a deep buccal groove in the lower molars, the absence of crista in the upper molars, the presence of a buccal and lingual cingulum and the larger dimensions. The size of the CHR M3 is larger than B. fatehjangense and well distinguished from this taxon ( Fig. 5 View FIG ).

Two brachypotheres are reported from Africa, B. snowi Fourtau, 1918 and B. lewisi Hooijer & Patterson, 1972 ; a third species B. heinzelini Hooijer, 1963 , known from Eastern and South Africa, must be restricted to the type specimen, while the rest material referred to it can be included to B. snowi ( Geraads 2010) . The species B. snowi is characterized by large size (larger than B. brachypus ), absence of cingulum, moderately developed antecrochet and very shallow buccal groove in the lower molars ( Geraads 2010) and differs from the studied material and B. brachypus . The other African taxon B. lewisi is much larger than B. brachypus and the studied teeth are well separated from it ( Fig. 5 View FIG ).