Versão online: http://www.lneg.pt/iedt/unidades/16/paginas/26/30/209 Comunicações Geológicas (2016) 103, Especial I, 117-120 ISSN: 0873-948X; e-ISSN: 1647-581X

Dinosaur tracks in the southwest Basin

Pegadas de dinossáurios no

V. F. Santos 1*

Artigo original Original Article © LNEG – Laboratório Nacional de Geologia e Energia IP

Abstract : In the Algarve Basin dinosaur tracks were discovered for the first at Praia Santa and Praia da Salema yielding theropod and time at Praia da Salema (, southwest Algarve) by Carlos Coke iguanodontian footprints (Santos et al. , 2000a,b, 2013). Iguanodontipus in 1995 during fieldwork in the area. Since then, research in this region has isp. was identified at Praia Santa. At Praia da Salema tridactyl allowed the identification of five dinosaur track levels of Early Barremian footprints with theropod affinity and an ornithpod trackway have age at Praia da Salema and Praia Santa (Vila do Bispo, southwest Algarve). been described. Here, tridactyl footprints with theropod affinity and iguanodontian footprints Before these findings Palain (1975, 1976) and Russell and assigned to Iguanodontipus isp. were identified. To the west of these sites, in the Upper Jurassic of Foia do Carro, sauropod trackways were also Russell (1977) revealed the presence of fish, primitive amphibians documented. Along this sedimentary sequence several isolated tridactyl and unknown reptiles in Triassic levels of the “Grés de Silves” footprints with ornithopod affinity were identified. Formation. Earlier fieldwork at Praia de Porto de Mós (Lagos, southwest Keywords : dinosaur footprints, Jurassic-Cretaceous, southwest Algarve, Algarve), in 1992, has allowed the geologist Pedro Terrinha to identify dinosaur teeth and longitudinal sections of vertebrae in a Resumo: Carlos Coke em 1995 fez a primeira descoberta de pegadas de layer of Aptian age that were tentatively assigned to theropods dinossáurios na Bacia Algarvia durante trabalhos de campo na Praia da Salema (Santos et al. 2000a; Santos, 2003; Santos et al., 2013). (Vila do Bispo, Barlavento Algarvio). Desde então a investigação desenvolvida na área permitiu a identificação de cinco camadas com estes icnofósseis na Praia da Salema e na baia imediatamente a oeste, na Praia Santa. Estes níveis atribuídos ao início do Barremiano têm pegadas tridáctilas de possíveis terópodes e de dinossáurios bípedes herbívoros semelhantes a Iguanodon atribuídas ao icnogénero Iguanodontipus isp. Para oeste destas jazidas, na Praia da Foia do Carro, foram detectadas pegadas de saurópodes em camadas do Jurássico Superior. Nesta sequência sedimentar também foram identificadas pegadas tridáctilas isoladas de prováveis ornitópodes. Palavras-chave : pegadas de dinossáurios, Jurássico-Cretácico, Barlavento Algarvio, Portugal

1 1Museu Nacional de História Natural e da Ciência, Rua da Escola Politécnica 58, 1250-102 Lisboa, Portugal. *Corresponding author/Autor correspondente: [email protected]

Fig. 1. Geological context of the three dinosaur tracksites from Vila do Bispo (southwest 1. Introduction Algarve); adapted from the Map 52-A (Portimão) of the Geological Map of Portugal, scale 1:50000, of the Serviços Geológicos de Portugal (Rocha et al ., 1983). Adapted During fieldwork in the Algarve Basin in 1995 the geologist Carlos from Fig. 2 in Santos et al . (2013). Coke discovered dinosaur footprints at Praia da Salema (Vila do Bispo, Fig. 1. Contexto geológico das três jazidas com pegadas de dinossáurio conhecidas no southwest Algarve) (Santos et al. 2000a; Fig. 1). Later Sebastião litoral de Vila do Bispo (Barlavento Algarvio); adaptado da Folha 52-A (Portimão) do Pernes and Maria do Carmo Ramalho told us about the location of two Mapa Geológico de Portugal à escala 1:50000 dos Serviços Geológicos de Portugal tracksites in this area, respectively at Praia Santa and at Foia do Carro (Rocha et al ., 1983). Adaptado da Fig. 2, Santos et al . (2013). (Fig. 1). A fieldtrip organized by Celestino Coutinho in 1996, has allowed the discovery of an ornithopod trackway by high-school students at Praia da Salema. With this cooperation dinosaur tracks were identified in the Upper Jurassic and Lower Cretaceous of the Algarve Basin (Santos et al ., 2000a,b; Santos, 2003). 2. Upper Jurassic sauropod tracks at Foia do Carro At Foia do Carro tracksite two levels with sauropod tracks were At Foia do Carro, a small bay towards west of Praia da Figueira identified. Five track levels of Early Barremian age were identified (Vila do Bispo, southwest Algarve), two Upper Jurassic sauropod 118 V. F. Santos / Comunicações Geológicas (2016) 103, Especial I, 117-120 track levels were identified and briefly described (Santos et al ., 2000a; Santos, 2003). At level 1 there are several faint impressions and some of them are in a sequence because they belong to one trackway. This trackway has oval impressions with 48 cm long by 33 cm wide and kidney shape prints with 28 cm wide by 18 cm long. The step length is about 1.30 m and the stride length is about 1.85 m. Inner trackway width is about 40 cm and the outer trackway width is about 1.15 cm. Track level 2 reveals a surface with a moderate trampling (according to the dinoturbation index proposed by Lockley and Conrad, 1989). Trackway with oval impressions with 80 cm long by 54 cm wide and kidney shape prints with 40 cm wide by 15 cm long. The best preserved impressions are deep with vertical margins. The step length is about 1.68 m and stride length is about 2.80 m. Inner trackway width is about 50 cm and the outer trackway width is about 1.60 cm. The general morphology of Foia do Carro tracks, their disposition along the trackway and the trackway width, allow us to assigned them to sauropods and to the Fig. 3. Seven small tridactyl footprints were identified at the east sector of Praia da ichnogenus Brontopodus . Salema (Vila do Bispo, southwest Algarve). Nowadays this slab is poorly preserved These sauropod trackways are similar to those from Pedra da due to marine erosion. Mua tracksite (Upper Jurassic, Cabo Espichel, Sesimbra) regarding Fig. 3. Sete pequenas pegadas tridáctilas foram identificadas no setor este da Praia da track morphology and trackway type (Santos, 2003). Salema (Vila do Bispo, Barlavento Algarvio). Atualmente esta laje está muito danificada pela erosão marinha. 3. Lower Cretaceous dinosaur tracks at Praia da Salema an outer indentation. Because these characteristics are like those In the west sector of Praia da Salema (Vila do Bispo, southwest endorsed to ornithopods this trackway was attributed to an Algarve) , underneath Salema school ( Escola Básica do 1º Ciclo de ornithopod, possibly an iguanodontian dinosaur with a hip height Salema ) and near the wooden stairs used to access the cliff base, a of about 2.2 m that could have been moving at 1.7 km/h, based on trackway of at least 13 very lined-up footprints with a pace Alexander’s (1976) equations (Santos et al ., 2013) . This trackway angulation value of about 170° were recognized in a horizontal slab was the first evidence of well-preserved ornithopod dinosaur (Fig. 2). footprints in Portugal (Santos et al ., 2000b). Notwithstanding the eroded impressions due to constant marine The other footprints are subcircular and they do not reveal any erosion, six of them are tridactyl and mesaxonic. They are as long morphological features. The average step and stride values are about (38 cm) as wide (37 cm), present marks of short fingers with parallel 70 cm and 1.4 m respectively but it is notable that the step shortens margins and U-shaped end and a symmetric heel mark an inner and (Santos et al ., 2013). Here it is possible to check how erosion changes the print morphology and this particular trackway reveals that sequences of subcircular impressions with a high value of pace angulation can be related at least with ornithopods. To the east of this slab along the cliff at Praia da Salema there are other levels with dinosaur footprints. One level known since 1995 yielded seven small tridactyl and mesaxonic footprints (Fig. 3): four isolated prints with long and slender digit marks and three other s that belong to a trackway (Santos et al ., 2000a; Santos, 2003). The morphology of these footprints suggests the presence of possible theropods whose posterior limbs were about 70 cm to 1 m long; one of them was walking at a speed of about 3.5 km/h (Santos, 2003). Due to constant marine erosion this occurrence is almost lost.

4. Lower Cretaceous ornithopod tracks at Praia Santa Three Lower Cretaceous dinosaur track levels were found at Praia Santa, to the west of Praia da Salema (Santos et al ., 2000b). The main level revealed four bipedal trackways and isolated prints. These are narrow sequences of tridactyl and mesaxonic footprints, almost as wide as long, with an inner and an outer indentation in the heel mark, wide and short prints of digits II, III and IV, with parallel edges and U shaped end (Santos et al ., 2013, Fig. 6). These well preserved footprints at Praia Santa reveal the characteristic morphology of ornithopod footprints and their similarity with the Fig. 2. Ornithopod trackway with at least 13 very lined-up tridactyl and subcircular prints attributed to Iguanodontipus isp. allow their inclusion in this impressions and a photograph of a segment of this sequence at Praia da Salema (Vila ichnogenus (Santos et al ., 2000b; Santos, 2003). The hip height of do Bispo, southwest Algarve). Adapted from Santos et al . (2013). these ornithopods range between 1.8 and 2.4 m and they were Fig. 2. Pista de um ornitópode com pelo menos 13 impressões tridáctilas e subcirculares walking at a speed of about 3.1 to 4.4 km/h. Dinoturbation and some muito alinhadas e fotografia de um segmento desta sequência de pegadas na Praia da isolated and poorly preserved tridactyl footprints were identified in Salema (Vila do Bispo, Barlavento Algarvio). Adaptado de Santos et al . (2013). this tracksite. Dinosaur tracks in the Algarve Basin 119

Fig. 4. A, B: Isolated tridactyl footprints with ornithopod affinity identified along the sedimentary sequence towards west of Praia da Salema (Vila do Bispo, southwest Algarve). The photographs courtesy of Sebastião Pernes. Fig. 4. A, B: Pegadas tridáctilas isoladas de prováveis ornitópodes são frequentemente encontradas na sequência sedimentar a oeste da Praia Santa (Vila do Bispo, Barlavento Algarvio). Fotografias gentilmente cedidas por Sebastião Pernes.

Along the coastline to the west of Praia da Salema there are 5. Conclusions other track levels with isolated or a sequence of two footprints with The cooperation between researchers and citizens who are aware of ornithopod affinity (Fig. 4). natural heritage has allowed the identification of dinosaur tracks in Isolated sauropod manus prints seem to be present along the the Upper Jurassic and Lower Cretaceous of the Algarve Basin, sedimentary sequence at Praia Santa (Vila do Bispo, southwest namely at Vila do Bispo shoreline (southwest Algarve). Algarve). Santos et al . (2013) referred the existence of poorly Upper Jurassic sauropod tracks were discovered at Foia do preserved kidney shaped marks which could be sauropod manus Carro, a small bay towards west of Praia da Figueira and were impressions but due to marine erosion the track morphology is not assigned to the ichnogenus Brontopodus (Santos et al ., 2000a; reliable to allow the assignment to a trackmaker. Santos, 2003). These track record put in evidence the presence in One particular isolated impression present in the sedimentary this area of a sauropod with a hip height of almost 2 m another one sequence at Praia Santa discovered by Brian Ottway seems to be a with 3 m to the hip. The estimated travel speed for these quadrupeds typical kidney shape sauropod manus print of about 20 cm wide by is about 4 km/h. 14 cm long (Fig. 5). The absence of other prints to associate them Five track levels along the Lower Cretaceous sedimentary in a trackway prevents any attempt to assign a dinosaur trackmaker sequence studied at Praia da Salema and Praia Santa (Vila do Bispo, to this print but this finding indicates a high probability to identify southwest Algarve) yielded footprints of possible theropods and sauropod tracks in this area. ornithopod footprints of Early Barremian age. Iguanodontipus isp. was identified at Praia Santa and there are evidences of the presence of iguanodontian dinosaurs with posterior limbs with a hip height of 1.8-2.4 m that moved at speeds ranging from 3.1 to 4.4 km/h. The ornithopod track record suggests that this dinosaur group was well-represented in the Iberian Peninsula and southwestern Europe during the Early Cretaceous (Santos et al ., 2013). Iguanodon , Delapparentia or other still unidentified or undescribed taxa from the Iberian Peninsula are the possible trackmakers of the footprints assigned to the ichnogenus Iguanodontipus (Santos et al ., 2013). At Praia da Salema it is possible to verify that a sequence of subcircular impressions with a high value of pace angulation can be related at least with ornithopods.

Acknowledgments Special acknowledgment are due to Diego Castanera, Carlos Neto de Carvalho and Alexandra Marçal for valuable comments that Fig. 5. The photograph is courtesy of Brian Ottway and displays an isolated typical improved this manuscript and to Sebastião Pernes and Brian Ottway kidney shape sauropod manus print of about 20 cm wide by 14 cm long (Praia Santa, who share with me photographs of dinosaur tracks from Praia da Vila do Bispo, southwest Algarve). Salema and Praia Santa. Special thanks go to Luis Santos for Fig. 5. Impressão isolada com forma de rim com cerca de 20 cm de largura por 14 cm technical help. de longitude, habitualmente atribuída à mão de um saurópode (Praia Santa, Vila do Bispo, Barlavento Algarvio). Fotografia gentilmente cedida por Brian Ottway. 120 V. F. Santos / Comunicações Geológicas (2016) 103, Especial I, 117-120

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