The Dasypodidae ( Mammalia , Xenarthra ) from the Urso Fóssil Cave ( Quaternary ) , Parque Nacional de Ubajara , State of Ceará , Brazil : paleoecological and taxonomic aspects

This paper deals with xenarthrans osteoderms assigned to Dasypus aff. D. novemcinctus, Euphractus sexcinctus and Cabassous sp. The material was collected in subsurface, from 0.10 to 0.60 m in the Urso Fóssil Cave, Parque Nacional de Ubajara, State of Ceará, northeastern Brazil. The ages of sediment samples from levels 4 and 5 (depths of 0.40 and 0.50 m) were determined by thermoluminescence technique, and indicated ages of 8,000 and 8,200 years BP for each layer respectively. The presence in these layers of early Holocene xenarthrans taxa can contribute to the understanding of the biotic evolution of the northwest region of Ceará during the last 10,000 years. Two of the three identified taxa still occur in the region: Dasypus novemcinctus and Euphractus sexcinctus. The Dasypodidae fauna here reported includes animals with generalist feeding habits and current wide geographical distribution. It is suggested, therefore, that the climatic and environmental conditions in the early Holocene were very similar the actual ones, and that the absence of Cabassous may be conditioned to other factors, such as anthropogenic action and loss of habitat by fragmentation of the vegetation.

PAULO V. OLIVEIRA, ANA MARIA RIBEIRO, ÉDISON V. OLIVEIRA and MARIA SOMÁLIA S. VIANA these families is questioned by some authors (e.g.Gaudin and Wible 2006).The Quaternary record of the Dasypodidae comes from South American Pleistocene and Holocene of Argentina, Bolivia, Brazil, Ecuador, Paraguay, Uruguay and Venezuela (Oliveira and Pereira 2009).
The armadillos are distributed from Oklahoma in the United States to south of the Strait of Magellan in Chile and were recently introduced into Florida (Eisenberg and Redford 1999).According to Wilson and Reeder (2005), the Dasypodidae includes 21 extant species distributed in nine genera that belong to three subfamilies: Dasypodinae, genus Dasypus Linnaeus, 1758; Euphractinae, genera Calyptophractus Fitzinger, 1871, Chaetophractus Fitzinger, 1871, Chlamyphorus Harlan, 1825, Euphractus Wagler, 1830and Zaedyus Ameghino, 1889;and Tolypeutinae, genera Cabassous McMurtrie, 1831, Priodontes F. Cuvier, 1825and Tolypeutes Illiger, 1811.In the Quaternary of Brazil, the Dasypodidae is represented by the genera: Propraopus Ameghino, 1881, Tolypeutes, Dasypus, Cabassous and Euphractus (Oliveira and Pereira 2009).Propraopus is an extinct taxon which occurs from the Pleistocene to the Holocene of Argentina, Brazil, Ecuador, Uruguay, Venezuela, and possibly of Bolivia and Paraguay; Tolypeutes is recorded for the Lujanian deposits (late Pleistocene) of Argentina (Paula Couto 1979); Dasypus occurs in the Pleistocene and Holocene of Argentina, Brazil, Uruguay and Venezuela (Oliveira and Pereira 2009); Cabassous is reported for the Pleistocene of Brazil (States of Minas Gerais and São Paulo; Paula Couto 1979); and Euphractus occurs in the Pampean of Argentina (Pleistocene) and it was possibly present in the Brazilian Pleistocene (Paula Couto 1979).
The material of Dasypodidae comprises several bone remains collected in the "Sala da Entrada" of the Urso Fóssil Cave, Parque Nacional de Ubajara (PNU), located in the northwest part of State of Ceará, Brazil.In the current faunal list, only Dasypus novemcinctus and Euphractus sexcinctus are recorded.The region integrating the karst system of the PNU lacks paleomastozoological studies, especially those involving smaller forms, such as armadillos.It is known that some small-sized and medium-sized species are highly specialized, and can provide important data regarding the occurrence of pronounced environmental changes during the Quaternary.Furthermore, taxonomic studies with species of these sizes are still rare in Brazil.
The main purposes of this paper are to present new records of Dasypodidae for the Quaternary mammal fauna of the Ubajara region and to provide information related to their geographical distribution and paleoecology.

GEOGRAPHIC AND STRATIGRAPHIC LOCATION
The Parque Nacional de Ubajara (PNU) is situated within the municipality of Ubajara, in the Ibiapaba cuesta, in the northwest of the State of Ceará (Figure 1).This is an area of a moist forest enclave on a plateau inserted in the Caatinga Biome, whose average elevation is around 900 m (Oliveira et al. 2011b).The Ibiapaba cuesta range runs north and south, comprising the boundary between States of Ceará and Piauí.Ibiapaba highland corresponds to the east edge of the Parnaíba Basin, which has a discordant contact with its east slope where Neoproterozoic Frecheirinha Formation (Ubajara Group, Ubajara Basin) crops out (Nascimento et al. 1981, Oliveira 2010).These outcroppings in the Ubajara region are characterized as limestone THE DASYPODIDAE FROM THE URSO FÓSSIL CAVE, CEARÁ, BRAZIL formations of exokarst.They comprise nine hills over 40 m of height (Nascimento-Junior and Paiva-Neto 2005) where 14 underground cavities with favorable conditions to the accumulation of modern and fossil organic remains, can be found (IBAMA 2002, Oliveira 2010).Among these cavities, the Urso Fóssil Cave 03°49'58''S/40°53'34.4''W in the Pendurado hill, stands out due to its high potential for paleontological studies, evidenced by the considerable accumulation of bone and dental specimens (Oliveira 2010, Oliveira et al. 2011a).The caves of the Ubajara region are less expressive in size (40 -1,120 m) when compared to other Brazilian caves (e.g.Toca da Boa Vista and Toca da Barriguda which are 107,000 m and 33,000 m long, respectively).This fact contributes to the accumulation of skeletal remains of a small and medium-sized fauna, mainly mammals.Until now there is only one reference related to the presence of Pleistocene megafauna in the region (Trajano and Ferrarezzi 1994).It is represented by a skull and mandible of Arctotherium brasiliense (= A. wingei Ameghino 1902, see Soibelzon 2004 for a systematic review of the Tremarctinae fossils in South America).
Teeth and vertebrae of reptiles were also found and reported by Hsiou et al. (2012).
The material presented here was collected in the first room of the Urso Fóssil Cave, known as "Sala da Entrada", which also includes numerous bone fragments which are still undetermined (highly fragmented), isolated teeth, seeds and gastropods already reported by Oliveira et al. (2011b).The material was collected in layers from 0.10 to 0.60 m, as shown in Figure 2. The ages of the layers 4 and 5 (0.40 and 0.50 m) were determined by thermoluminescence (TL), resulting in 8,000 ± 990 years BP and 8,200 ± 980 years BP (early Holocene), for each layer respectively.

SySTEMATICS
The semi-moveable osteoderms (specimens MDJ M-834, 949 and 1044) are from a transitional area and therefore share ornamentation patterns with both fixed and moveable osteoderms.The semi-moveable osteoderms may exhibit two sulci.Under the sulci there are some unpaired foramina, as well as some punctuations.The latter are also present in the central area between the two sulci.
The moveable osteoderms include complete specimens and fragments of several sizes.The complete movable osteoderms are elongated and have two portions (see Figure 4D-E, Table I).The anterior portion corresponds to the articulation area and it is smooth and table-like shaped, i.e., it is higher and thicker than the posterior portion.The surface of the table-like area is irregular due to the presence of dorsal ornamentations, such as foramina and sulci.The transition between the anterior and posterior portions is marked by a difference in thickness, but also by the presence of roughness.Still on the dorsal surface, on the anterior limit of the posterior portion, it is observed that two sulci originate very close to each other, but then diverge posteriorly.In some specimens these sulci seem to limit an elongated and subtriangular figure, similar to an isosceles triangle, with the basis towards the distal edge of the osteoderm.In this region of the osteoderm usually there are four foramina, possibly from hair follicles.Smaller foramina occur in the two aforementioned sulci and they can vary in number, arranged anteroposteriorly, paired or unpaired.Also, in the area between these sulci there are punctuations, smaller than the foramina.The lateral articular surfaces show strongly serrated edges in general.The ventral surface THE DASYPODIDAE FROM THE URSO FÓSSIL CAVE, CEARÁ, BRAZIL of the osteoderm may be flat or slightly concave, lacking ornamentation.The peripheral figures also show some punctuations.The specimen MDJ M-860 corresponds to the last osteoderm (right edge) of the sequence of moveable bands.The osteoderms MDJ M-862, 869, 906-909, 937, 945, 1054-1056, 1067 and 1068, belong to the first row of one of the tail rings.The anterior portion is table-like and much reduced, whereas the posterior portion is larger and exhibits the following ornamentations: one medial sulcus which branches to both sides in two sulci, in which there are two pairs of foramina.The last pair reaches the lateral edge, where two pairs of foramina are also present.
Thus, forming one pentagonal figure with an irregular surface.The distal end is V-shaped and it is articulated to the anterior end of the osteoderms from the second row of the caudal ring.The specimens MDJ M-859, 910, 911, 946 and 947 belong to the second row of the tail ring, which presents five edges and bears a V-shaped proximal end.The MDJ M-802 belongs to a ring of the distal portion of the tail and like the others, it has two portions (proximal and distal), lacking ornamentation.The ventral surface of the specimen is concave and bears some lines arranged longitudinally.However, the most distal portion of the surface is smooth, such as is observed in MDJ M-1057.which is more elongated than in other specimens.These morphological differences are due to the fact that osteoderms come from different places in the carapace.MDJ M-803 has two foramina for hair follicles, only visible in the ventral surface, due to the fragmentation of its distal end.The semi-moveable osteoderms MDJ M-1116 and 1120 belong to an intermediate zone, between the scapular portion of the carapace and the first row of moveable osteoderms.The material bears a well-marked sulcus with an inverted U-shape.From this sulcus four or five sulci reach the anterior end of the osteoderm, bordering three to four peripheral figures.The foramina for hair follicles are restricted to the end of the posterior portion and vary in number (three or four).

Osteoderm
The moveable osteoderms are represented only by fragments.The specimens MDJ M-823 and 824 are similar in morphology.Both display a very marked division of the dorsal surface into anterior and posterior regions.The anterior region apparently lacks ornamentation, whereas the posterior one is well ornamented by two sulci that originate in this medial region.Due to their poor preservation, it is not possible to observe the presence of foramina in MDJ M-823 and 824, unlike MDJ M-1119, which has its posterior portion preserved, and two sulci that contain three foramina each, as well as two other foramina for hair follicles at the distal end, can be seen.The lateral articular surfaces of the specimens present a rough area, unlike the ventral surface which is smooth, convex laterally and medially concave.The specimen MDJ M-872 belongs to the lateral edge of the carapace and differs from other moveable osteoderms by the lack of ornamentation and by its irregular shape.The dorsal surface of the specimen is convex and the ventral one is concave.Both surfaces have a smooth aspect.The specimen MDJ M-820 corresponds to a molariform tooth, which is semicircular in occlusal view and cylindrical in lingual and labial views.The tooth presents two crests located on the most anterior region; one crest is vestibular and the other lingual.Description.The MDJ M-1113 is slightly hexagonal, but its surface is of a different size, contributing to an anteroposteriorly elongated aspect.The specimen possibly belongs to the second or third row of the scapular portion of the carapace and its dorsal surface is marked by small and shallow punctuations and a wellmarked sulcus in an inverted U-shape.Concerning the moveable osteoderms, they are rectangular in THE DASYPODIDAE FROM THE URSO FÓSSIL CAVE, CEARÁ, BRAZIL shape, their dorsal surface is ornamented and the ventral surface is smooth and slightly lowered at the center in longitudinal axis.The anterior portion is table-like, smooth and smaller than the posterior portion.Between the anterior and posterior portions, there is an ornamented area, although the posterior portion itself does not have ornamentation, but only some punctuations and foramina for hair follicles at the distal end.The measurements of the specimens are in Table III

DISCUSSION AND CONCLUSIONS
The analysis of the osteoderms from the Urso Fóssil Cave was carried out by comparison with extant Dasypodidae taxa of the region, as well as by comparison with those recorded for the late Pleistocene and Holocene of Brazil, and belonging to the following taxa: Dasypus, Cabassous, Euphractus, Tolypeutes and Propraopus.The specimens studied here are diverse in shape, size and ornamentation, reflecting the characteristics of different species, and the different positions they occupied in the carapace.
Based on a literature review concerning the studies of the Caatinga and its fauna, which was published between the years 1887 and 2000, Oliveira et al. (2003) provided a list of mammal species that occur in the Caatinga.According to this list, Dasypus septemcinctus, D. novemcinctus, Cabassous sp., Euphractus sexcinctus and Tolypeutes tricinctus occur in the States of Alagoas, Bahia, Ceará, Minas Gerais, Paraíba, Pernambuco, Piauí, Rio Grande do Norte and Sergipe.Although they are taxa with broad current distribution in Brazil, their occurrence as fossils is rather scarce (see Figure 5).
Regarding the deficiency in data related to small and medium-sized fossil mammals, we believe this happens because most publications are concerned with the study of megafauna, and because of the lack of use of specific methods to collect remains of small animals.Eisenberg and Redford 1999).In evidence the fossil occurrences according to Ameghino (1907), Paula Couto (1973, 1979, 1983), Guérin et al. (1996), Faure et al. (1999), Salles et al. (2006), Oliveira and Pereira (2009)

Figure 1 -
Figure 1 -Location map of the National Park of Ubajara, State of Ceará (above) and the limestone outcroppings (below) indicated by arrows.Modified from Oliveira et al. (2011b).

TABLE I Measurements (mm) of preserved osteoderms assigned to Dasypus aff. D. novemcinctus. Abreviations: TL, total length; PW, proximal width; DW, distal width; PT, proximal thickness; DT, distal thickness. When n >1, first line is mean ± standard deviation, second line is observed range, and third line is number of specimens measured (n).
The specimen MDJ M-803 differs from the other fixed osteoderms due to the absence of foramina and the presence of a shallow sinuous sulcus, PAULO V. OLIVEIRA, ANA MARIA RIBEIRO, ÉDISON V. OLIVEIRA and MARIA SOMÁLIA S. VIANA

TABLE II Measurements (mm) of preserved osteoderms assigned to Euphractus sexcinctus. Abbreviations: TL, total length; PW, proximal width; DW, distal width; PT, proximal thickness; DT, distal thickness. When n >1, first line is mean ± standard deviation, second line is observed range, and third line is number of specimens measured (n).
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