New endemic eocene equoids from the Iberian Peninsula (Western Europe)

Badiola, Ainara, Ruiz-Colmenares Cuesta, Ángel Miguel

Description

Colecciones : DGL. Documentos de trabajo del Departamento de Geología
Fecha de publicación : 2008
[EN] A new plagiolophine equoid from the Eocene of the Iberian Peninsula, Iberolophus gen. nov., is herein reported. This new genus includes two species: I. arabensis sp. nov. (type species) from the Late Eocene (Headonian) of Zambrana (Araba, Basque Country) and I. jimenezi sp. nov. from the late Middle Eocene (Robiacian) of Mazaterón (Soria, Castilla y León). Iberolophus exhibits an unusual dental pattern that has not yet been reported in any other perissodactyl or ungulate to date. A complete (with P1/p1) and very long non-lophoid premolar series, in which premolars exhibit one (in the earlier members) or two (in the later members) high and pointed cusp(s) anteriorly and a low and long backward extended talon/talonid posteriorly, with a bumpy surface texture, is combined with a typical plagiolophine type lophodont and heterodont molar series. The new taxa are ranked as members of the endemic fauna of the Western Iberian Bioprovince. The latter includes the Eocene sites of the central and western Iberian basins (Duero, Almazán, Oviedo, and Miranda-Trebiño Basins), which have yielded Middle and Late Eocene mammal fossil assemblages (mainly perissodactyls, rodents and primates) which differ from those of the Southern Pyrenean Basins and the rest of Europe. The endemism of the perissodactyl faunas persisted during the Late Eocene in the central and western Iberian basins, on the basis that the perissodactyl fossils from the middle Headonian beds at Zambrana (Miranda-Trebiño Basin) are related to endemic taxa from the late Robiacian beds of the Duero, Almazán, and Oviedo Basins.

Sujets

• Sciences et techniques

Informations

• Publié par: Salamanca
• Nombre de lectures: 59
• Licence : En savoir +
  Paternité, pas d'utilisation commerciale, partage des conditions initiales à l'identique
• Langue: Español
• Poids de l'ouvrage: 2 Mo

Extrait

Journal of Vertebrate Paleontology 28(4):1149–1161, December 2008 © 2008 by the Society of Vertebrate Paleontology

ARTICLE

NEW ENDEMIC EOCENE EQUOIDS FROM THE IBERIAN PENINSULA (WESTERN EUROPE) AINARA BADIOLA *,1 and MIGUEL-ÁNGEL CUESTA 2 1 Departamento de Ciencias de la Tierra, Área de Paleontología, Facultad de Ciencias, Universidad de Zaragoza, Pedro Cerbuna, 12, E-50009 Zaragoza, Spain, [e-mail] 2 Departamento de Geología, Facultad de Ciencias, Universidad de Salamanca, Plaza de los Caídos s/n, E-37008 Salamanca, Spain

ABSTRACT—A new plagiolophine equoid from the Eocene of the Iberian Peninsula, Iberolophus gen. nov., is herein reported. This new genus includes two species: I. arabensis sp. nov. (type species) from the Late Eocene (Headonian) of Zambrana (Araba, Basque Country) and I. jimenezi sp. nov. from the late Middle Eocene (Robiacian) of Mazaterón (Soria, Castilla y León). Iberolophus exhibits an unusual dental pattern that has not yet been reported in any other perissodactyl or ungulate to date. A complete (with P1/p1) and very long non-lophoid premolar series, in which premolars exhibit one (in the earlier members) or two (in the later members) high and pointed cusp(s) anteriorly and a low and long backward extended talon/talonid posteriorly, with a bumpy surface texture, is combined with a typical plagiolophine type lophodont and heterodont molar series. The new taxa are ranked as members of the endemic fauna of the Western Iberian Bioprovince. The latter includes the Eocene sites of the central and western Iberian basins (Duero, Almazán, Oviedo, and Miranda-Trebiño Basins), which have yielded Middle and Late Eocene mammal fossil assemblages (mainly perissodactyls, rodents and primates) which differ from those of the Southern Pyrenean Basins and the rest of Europe. The endemism of the perissodactyl faunas persisted during the Late Eocene in the central and western Iberian basins, on the basis that the perissodactyl fossils from the middle Headonian beds at Zambrana (Miranda-Trebiño Basin) are related to endemic taxa from the late Robiacian beds of the Duero, Almazán, and Oviedo Basins.

INTRODUCTION Araba) and an older species comes from the late Middle Eocene FromthelateEarlyEocenetotheearliestOligocene,Europe b u e su ds al a d t en M t a al za p t a e t r t ó e n rn ( t A h l a m t a h z a á s n n B ot as y i e n t ,S be or e i n a) r . e T po h r e t y ed ex i h n ib a i n t y a o n th u e n r - was an archipelago inhabited by an endemic mammalian fauna, which was clearly different from the contemporary fauna in  perissodactyl or ungulate to date. On the basis of the molar series North America and Asia. Perissodactyls were one of the most  features, they have been assigned to the Plagiolophinae subfamily abundantEocenemammalianfaunaandconsistedofamainly f C a u u e n s a ta, of 19 t 9 h 4 e a. W T e h s e te n r e n w I t b a e x r a ia ar n e B ra io n p k r e o d vi a n s c m e e (s m e b e er l s as o t f s t e h c e ti e o n n d ) e . mic tapir-like group known as lophiodonts and a horse-like group  The Zambrana site is situated near the village of Zambrana known as equoids. Many of these European endemic mammals becameextinctintheearliestOligocenesynchronouslywiththe l ( o A g r ic a a b l a l , y, B t a h s e qu f e os C si o li u fe nt r r o y u ) s ,a b b e o d u s t , 7 w 0 hi k c m h s c o o u n t s h ist of of Bil p b a a lu o. str G in e e o- - appearance of Asian immigrants, in an event named by Stehlin  lacustrine coal bearing marls and marlstones, are located in one (1909) the “Grande Coupure” (e.g., Brunet, 1977; Prothero, 1985; Hooker, 1992; Blondel, 2001; Hooker et al., 2004).  of the oldest lacustrine systems from the Miranda-Trebiño Basin In the Iberian Peninsula, there was a wide diversity of peris-  (Basque-Cantabrian Region) (Astibia et al., 2000; Fig. 1A). The sodactylsduringtheEocene.Afaunallistwasincludedinthelast l d a e k p e os m it a i r o g n i a n ls w e i t t t h in a g p w e a r s ip a he s r h a a l ll s o w w a a m n p d ( l I o ri w a - r g te ra e d t ie a n l t ., fr 2 e 0 s 0 h 3) w . at T e o r synthesis on Eocene mammal faunas presented at the Paleogene biochronological congress which took place in Montpellier  date, 25 vertebrate taxa have been recovered. They consist of (France) in 1997 (see Antunes et al., 1997). This was subse-  anurans, squamates, chelonians, crocodilians, and mammals, in- quently updated by Checa (1997), Cuesta (1999, 2003), and Ba-  cluding herpetotheriid marsupials, rodents, carnivores, artiodac- diola(2004).TherecordedbiodiversityoftheIberianEocene t d y i l o s l , a a a n n d d pe C r u is e s s o ta d , ac 2 t 0 y 0 l 7 s a ( ; A B s a ti d b i i o a la et et al a ., l., 20 2 0 0 0 0 ; 2, B 2 a 0 d 0 i 5 o ) l . a, A 20 p 0 r 4 i ; m B at a e - perissodactyls is increasing. Eight new equoid taxa, of which  mandible was recently found during the most recent field work. three are new genera, have recently been reported by Badiola et al.(inpress).Detailsoftwoofthesehavealreadybeenpub- P er e a ri a ss n o d d t a h c r t e yl e s s c p o e n c s i i e st s) o a f r s e ev n e e n w e t q a u xa oid as s, m of en w ti h o ic n h ed fiv a e bo ( v t e w . o Z g a e m n- - lished; one refers to a new genus as Bepitherium jordifusalbae brana is currently the first Paleogene locality in the Iberian Pen- Checa and Colombo, 2004 and the other refers to a new species  insula to have yielded a fossil mammal assemblage belonging to as Pachynolophus zambranensis Badiola, Pereda and Cuesta, 2005.Theothernewtaxaconsistoftheunpublishedspeciesof the Th M e P M 1 a 8 z r a e t f e e r r ó e n nc si e te le i v s e s l. ituatednearthevillageofMazaterón Leptolophus Remy, 1965 and Palaeotherium Cuvier, 1804 and two new plagiolophine genera (Badiola, 2004). In this paper, one  (Soria, Castilla y León) about 40 km southeast of Soria. Geo- ofthetwonewequoidgeneramentionedpreviouslyisdescribed, l i o n g c i l c u a d ll e y d ,t w h it e hi g n re t y he m M ar a ls za t t h e a r t ón co F n o t r ai m n at t i h o e n, ve w r h t i e c b h ra c t o e n f si o s s t s s il o s f a l r a e - being represented by two species. The type species comes from theLateEocenebedsatZambrana(Miranda-TrebiñoBasin, c A u l st m r a in zá e- n pa B l a u s s i t n ri , ne wh l i i c m h e i s s to s n it e u s at a e n d d in m t a h rl e s. e I a t st i e s rn lo s c e a c t t e o d r i o n f t t h h e e Duero Basin (Fig. 1B). The depositional setting is a shallow * Corresponding author. lacustrine system, which was subjected to constant flooding and 1149