Lourinhasaurus alenquerensis, (LAPPARENT & ZBYSZEWSKI, 1957)

Mocho, Pedro, Royo-Torres, Rafael & Ortega, Francisco, 2014, Phylogenetic reassessment of Lourinhasaurus alenquerensis, a basal Macronaria (Sauropoda) from the Upper Jurassic of Portugal, Zoological Journal of the Linnean Society 170 (4), pp. 875-916 : 879-897

LOURINHASAURUS ALENQUERENSIS ( LAPPARENT & ZBYSZEWSKI, 1957)

1957 Apatosaurus alenquerensis Lapparent & Zbyszewski, 1957

1990a? Camarasaurus alenquerensis McIntosh, 1990a

1990b? Camarasaurus alenquerensis McIntosh, 1990b

1996b? Camarasaurus alenquerensis McIntosh et al. 1996b

1998 Lourinhasaurus alenquerensis Dantas et al. 1998

2003 Lourinhasaurus alenquerensis Antunes & Mateus, 2003

Lectotype: Partial skeleton ( Fig. 2D ) housed in MG LNEG composed by: cervical vertebrae remains (MG4956, MG30373, MG30377, and MG30379), 12 dorsal vertebrae and several neurapophyses fragments (MG4956: 11 dorsal centra; MG30378: the cranialmost dorsal centra; MG30384: neurapophyses fragments), several cranial-to-caudal dorsal ribs (MG30370), five sacral vertebrae (MG4956), sacral ribs (MG30380)* and three sacral neural spines (MG30376)*, three proximal vertebrae and two proximal caudal neurapophyses (MG4956, MG30374, MG30388), chevron fragments (MG30387)*, left (MG 5780) and right (MG30371) scapulae, left (MG5780) and right (MG30372) coracoids, left (MG30383) and right (MG30382) sternal plates*; left (MG2) and right (MG30381) humeri, left radius (MG4979), left ulna (MG4979), carpal II (MG30385), left ilium (MG5781), right (MG4975) and left (MG4970) pubis, left and right ischia (MG4957), left femur (MG4931), left tibia (MG4983), left fibula (MG4984), left astragalus (MG30375), pedal (?) phalanx 2 (MG30386)* and other several indeterminate fragments without explicit acronyms. All these elements are labelled and related to a unique individual, but some elements (marked with an asterisk) were not explicitly referred to in the original description ( Lapparent & Zbyszewski, 1957); and there are some elements, originally quoted by these authors, that cannot be recognized in the available set of elements.

Emended diagnosis: Macronarian having the following autapomorphies: (1) cranial-to-middle dorsal vertebrae with transversely concave ventral face bounded by longitudinal smooth crests; (2) sagittal keel in dorsal margin of sacral neural spines; (3) when the sacral neural spines are vertical becomes significantly higher caudally, and the dorsal margin bears a marked cranial slope; (4) prespinal process with a sagittal lamina (prespinal lamina) in the dorsal sector of the sacral spine subdividing a smooth prespinal fossa; (5) circular and deep spinoprezygapophyseal fossa on proximal caudals (also shared by Jobaria ); (6) the dorsal surface of the most proximal caudal spine slopes cranially transiting continuously to the cranial face of the spine, and the caudal edge produces a transverse hooked-like process in lateral view; (7) circular process on distal surface of carpal II; (8) longitudinal crest in ventral margin of ilium postacetabular process near ischiatic peduncle; (9) caudal orientation of the postacetabular process with the chord through the ischiatic and pubic articulations passing through ventral margin of the postacetabular process; (10) axis of pubic peduncle and ischiatic articulation parallel; (11) marked crest and groove bordering the lateral margin of acetabulum in the ischium; (12) tibia and fibula of equal length, implying a more distal position of the fibula relative to the tibia for the reception of the astragalus; (13) marked deflection of the entire femoral shaft without lateral bulge.

Etymology: Lourinhasaurus, Lourinha , from Lourinhã, a municipality north of Lisbon where one of the specimens related to this taxon was found ( Dantas et al., 1998), later considered as the holotype of Dinheirosaurus lourinhanensis ( Bonaparte & Mateus, 1999) ; saurus, greek for lizard; and alenquerensis , from Alenquer, a municipality north of Lisbon where the lectotype specimen of the taxon was found.

Horizon and locality of the lectotype: Moinho do Carmo, Alenquer municipality, north of Lisbon, Sobral Formation (or Sobral Member of the Farta Pão Formation sensu Schneider et al., 2009), upper Kimmeridgian to lower Tithonian, Lusitanian Basin.

DESCRIPTION

AXIAL SKELETON

Cervical vertebrae: A cranial-to-middle (MG30377, Fig. 3A, B ) and a middle-to-caudal (MG30373, Fig. 3C, D ) cervical vertebra as well as several fragments (e.g. MG4956) were identified. The most complete centrum (slightly fractured caudally, MG30373) is transversely constricted in the middle sector and shows an elongation index (sensu Upchurch, 1998) of 1.8. The ventral face is flat to slightly concave and is limited by marked lateral margins resembling crests ( Fig. 3D ). The pleurocoels are deep, occupying most of the length of the centrum, and are separated by a 20-mm-thick sagittal plate. Each pleurocoel is laterally divided by at least one vertical lamina, creating two main cavities. Internally, the pleurocoels are divided into several cavities. Considering the morphological categories defined by Wedel, Cifelli & Sanders (2000), the cervical vertebrae of Lourinhasaurus bears polycamerate pneumaticity.

MG30377 ( Fig. 3A, B ) and a caudal cervical neurapophysis lacking the distal portion of the spine and the parapophyses, pre- and postzygapophyseal processes (MG30379, Fig. 4 ), were identified. In MG30377, the neurapophysis is displaced and slightly rotated relative to its original position. In lateral view, dorsal to the pleurocoel margin, there is a marked posterior centrodiapophyseal lamina (pcdl) that has an arched profile and slopes lateroventrally. In MG30377, below the pcdl, there is a centrodiapophyseal fossa (cdf) that is subdivided into two smooth subfossae. These subfossae are considered homologous to two deep circular foramina below the pcdl present in MG30379, and in the later element (MG30377) being separated by a stout vertical accessory lamina emerging from the pcdl. In the most cranial vertebrae (MG30377), the postzygodiapophyseal lamina (podl) emerges from the diapophysis, whereas in the caudalmost cervical neurapophyses (MG30379) this lamina has a more caudal position, emerging from the pcdl at an angle of 45°. The podl is smoother in MG30379, becoming more prominent caudally. The pcdl and podl border a subtriangular postzygapophyseal centrodiapophyseal fossa (pocdf) that consists of two sectors, a cranial sector facing laterally and a caudal sector facing more caudolaterally to which the cranial sector progressively transits. In the most cranial cervical vertebra (MG30377), there is a smooth accessory lamina between the pcdl and the podl that emerges from the diapophysis and is orientated parallel to the pcdl. In caudal view, the pocdf displays a smooth subfossa in its dorsal sector.

In MG30379, the podl bifurcates into two laminae, a cranial and subhorizontal lamina that is interpreted as the epipophyseal–prezygapophyseal lamina (eprl) and a caudal and subhorizontal lamina that is the caudal continuation of the podl toward the postzygapophyses (this sector is not preserved in the most cranial vertebrae). The eprl divides the sector above the diapophysis into two fossae, the dorsal spinodiapophyseal fossa 1 (sdf1), which is bordered at least by the eprl and the podl, and the ventral spinodiapophyseal fossa 2 (sdf2), which is located cranially to the podl and is bordered dorsally at least by the eprl. In a lateral view of MG30377, unlike in MG30379, there is no subdivision of the sdf. In MG30377, it is possible to recognize two other laminae, the prezygodiapophyseal lamina (prdl) and an accessory vertical lamina that emerges from the prdl and divides the sdf into two fossae. This accessory lamina emerges from prdl and is craniodorsally developed being considered non-homologous of the eprl observed in MG30379. The eprl is a lamina that connects the epipophyses to the prezygapophyses ( Wilson, 2012). Therefore, the two subfossae observed in the sdf are not considered homologous to sdf1 and sdf 2 in the most caudal cervical spine.

The cranial and caudal sectors of both cervical neurapophyses are not well preserved. In cranial view, one can observe the presence of a spinoprezygapophyseal fossa (sprf) with a smooth surface limited by the spinoprezygapophyseal laminae (sprl) that diverge laterally.

Dorsal vertebrae: Herein, on the basis of the pictures and quarry map in Lapparent & Zbyszewski (1957), the relative positions of the 12 preserved dorsal centra are tentatively assigned ( Fig. 5 ). The total number of dorsal vertebrae is unknown for this specimen. Each centrum is described by its relative position, from cranialmost (DV1) to caudalmost (DV12) centrum. Because the centra show strong and variable deformation, it is difficult to obtain reliable values for the elongation index (EI). The leastdeformed centrum (DV10) has an EI of 1.12. Every dorsal centrum is strongly opisthocoelous and has a central circular depression in the cranial articulation. The centra are transversely constricted at midlength and have transverse subcircular outlines ( Fig. 6A–C ). The centra from DV3 to DV6 bear a craniocaudal concavity along their ventral faces, a feature that is considered an autapomorphy of Lourinhasaurus alenquerensis ( Figs 5 , 6D ). In DV5, this concavity is restricted to the cranial sector of the ventral face. The craniocaudal concavities are laterally limited by craniocaudal crests, producing a biconvex transverse outline of the centrum ventral face. In the DV2 and from the DV7–DV12 centra, the ventral face is slightly flat-to-convex and transits continuously toward the lateral face. In general, the radial length of the caudal face is larger than that of the cranial face. Every vertebra bears deep pleurocoels located craniodorsally on the lateral face of its centrum and occupying ½ to 2 ⁄ 3 of the lateral central length. The pleurocoels of the cranial dorsal centra have elliptical outlines that are compressed dorsoventrally and taper cranially and caudally, becoming progressively rounded and smaller toward the most caudal centra. The pleurocoels are ventrally expanded and are separated by a sagittal lamina 20 mm thick that is quite constant along the dorsal sequence. Cranially, the pleurocoels become deeper and more complex with few ramifications in the cranial and caudal zones of the centrum ( Fig. 7 ). The dorsal vertebrae of Lourinhasaurus bear a polycamerate to camerate pneumaticity (sensu Wedel et al., 2000). The neural arches are placed cranially and do not occupy the caudal part of the dorsal face of the centrum. In the last preserved dorsal centra, DV11 and DV12, the neural arches occupy the entire craniocaudal extension.

The most cranial dorsal centrum preserves the left parapophysis and is located near the craniodorsal margin of the pleurocoel. Below the parapophysis, two laminae emerge from its caudoventral margin, a cranial subvertical lamina that slopes backwards and a medial subhorizontal caudal lamina. These laminae border the excavated region below and behind the parapophyses, displaying a subtriangular contour. The cranial subvertical lamina and the medial subhorizontal caudal lamina are probably homologous to the anterior centroparapophyseal lamina (acpl) and the posterior centroparapophyseal lamina (pcpl), respectively. This fossa probably communicates with the pleurocoel caudally or corresponds to a subdivision of the pleurocoel. Above the ‘pcpl’, there is a small subtriangular fossa. The parapophysis surface is excavated and has a transverse subrectangular outline.

Some remains of neurapophyses (DV6 – MG4956, in which the neurapophysis is collapsed, and MG30384 fragments) were identified and were assigned to middle centra ( Fig. 8 ). On these fragments, it is possible to observe the presence of a stout acpl that bifurcates ventrally near the dorsal margin of the pleurocoel where the caudal branch reaches the caudoventral margin of the neural arch. Between the two branches of the acpl, there is a smooth fossa that lies craniodorsal to the pleurocoel. Caudal to the caudal branch of the acpl, a pcdl bifurcates ventrally into two branches that border a small but well-marked teardrop-shaped fossa. The caudal branch reaches as far as the caudal margin of the neurocentral junction. The acpl structure and pcdl limit another fossa, the parapophyseal centrodiapophyseal fossa (pacdf). A second cranially directed lamina is broken, and it is difficult to determine whether this lamina represents the ppdl.

The prezygapophyses are robust and are supported ventrally by a cprl and a prpl. The cprl is bifurcated dorsally close to the prezygapophyses. Between the cprl and the prpl, there is an accessory lamina (al), dorsoventrally developed, that begins considerably below the prezygapophysis. The preserved sector of the centroprezygapophyseal fossa (cprf) is deep and flat (DV6 – MG4956 and MG30384). The postzygapophyses are circular in contour, and their surfaces are flat to concave. The centropostzygapohyseal lamina (cpol) is columnar and delimits a shallow centropostzygapophyseal fossa (cpof).

The unique preserved neural spine is probably a fragment of the 6th or 7th dorsal spine ( Fig. 9 , MG30384), based on comparison with the dorsal series of Camarasaurus (e.g. Osborn & Mook, 1921). This spine is basally constricted and transversely expanded in the dorsal direction. The dorsal margin of the neural spine bears a sagittal concavity, laterally bounded by two small round rod-like dorsal processes 35 mm in height. Comparing several dorsal vertebrae series with non-bifid and bifid neural spines (e.g. Hatcher, 1901, 1903; Osborn & Mook, 1921; Janensch, 1929; Gilmore, 1936; Powell, 1992; McIntosh et al., 1996a, b; Tang et al., 2001; Ikejiri, 2004; Campos et al., 2005; McIntosh, 2005; Curry Rogers, 2009), the presence of a concavity in the dorsal margin corresponds to the transition between bifid and non-bifid neural spines. Laterally, these processes extend downward into the triangular rounded lateral process. The morphology of the spine in cranial or caudal view is roughly rhombus-like. The lateral boundary is probably an spol laminae tapering ventrally. The caudal surface is concave and rough. The cranial face is convex and broken in the prespinal area, lacking the prespinal process.

Dorsal ribs: Several distal to proximal fragments of dorsal ribs were identified. Only one caudal dorsal rib (a right one) preserves part of the capitulum and lacks the tuberculum in the proximal zone ( Fig. 10A, B ). All preserved dorsal ribs present a solid bone tissue. The caudal and the cranial face of proximal section are both concave and there is no sign of a pneumatopore in the caudal surface. The proximal sections of cranialmost ribs display a pronounced and laterally displaced crest (it probably meets with the tuberculum) on the cranial face and a concave caudal face. In cross-section those proximal sections show a ‘T’ outline ( Fig. 10C ). The middle and the distal sectors of the ribs are ‘plank’-like bearing an elliptical cross-section (the craniocaudal length is three times the lateromedial length) in their distal portions.

Sacral vertebrae: The sacral region is composed of five fused vertebrae ( Fig. 11A, B ). The sacrum shows a slight curvature (convexity faces ventrally); consequently, the last sacral caudal articulation faces craniodorsally. The centra are as tall as they are long and are transversely constricted at midlength. Beneath the surface of the broken transverse processes, a wide depression occupies much of the lateral face, but only the first sacral vertebra bears a true pleurocoel that is craniocaudally shorter than the dorsal pleurocoels. The lateral face of the centrum slopes medioventrally and passes continuously to the ventral face. The ventral face is mediolaterally narrow, as occurs in other sauropods such as Tastavinsaurus (Royo-Torres, 2009) and Lusotitan (P. Mocho, pers. observ., 2011).

The first sacral centrum is strongly convex cranially. The state of the other sacral centra is unknown because they are fused. Excluding the first sacral vertebra, it is possible to recognize, at the dorsocranial area of the lateral face, the presence of transverse processes that are broken at their bases. These transverse processes project craniolaterally and have subrectangular to elliptical cross-sections that are craniocaudally elongated. These structures maintain the same shape and size along the entire sacral sequence.

There is a sequence of three neural spines (two of them fused) that are constricted at their bases ( Fig. 11C ). The lateral face of these spines presents a smooth subrectangular fossa that is limited by sprl and spol. The triangular dorsal processes of the spines develop toward the lateral face, converging to a pronounced spdl. The spdl is closer to the spol than to the sprl. The dorsal margin of these spines is acute, producing a craniocaudal crest along the dorsal margin of the sacral neural spines. This is considered an autapomorphy of Lourinhasaurus alenquerensis ( Fig. 11D–F ). When the spines are verticalized, the dorsal margin of the sacral spines slopes cranially in lateral view, because the spines become higher caudally ( Fig. 11C ). Another possibility it is to consider that the dorsal margin of the sacral spines is horizontal, resulting in an important cranial slope of the sacral neural spines, also uncommon in sauropod sacrums (e.g. Osborn, 1904; Osborn & Mook, 1921; Janensch, 1929; Suteethorn et al., 2009). Therefore, the marked cranial slope of the dorsal margin of the fused sacral neural spines when verticalized is a unique feature of Lourinhasaurus alenquerensis . This configuration could be related to the caudal dorsal deflection of the sacrum. The most caudal sacral spine bears a broad spinopostzygapophyseal fossa (spof) bordered by a thick spol. The cranial and caudal surfaces of this spine are rough, and there is a shallow and wide prespinal process. The dorsal sector of this prespinal process is excavated by a smooth fossa subdivided by a sagittal lamina, considered here as a prespinal lamina ( Fig. 11D, E ). This configuration is exclusive to Lourinhasaurus alenquerensis .

Two fragments of the iliac bar (MG30380) are preserved; they are strongly expanded distally, showing oval outlines in distal view.

Caudal vertebrae: Lapparent & Zbyszewski (1957) recognized five caudal vertebrae. In fact, three proximal caudal vertebrae and two non-corresponding proximal neural spines, as well as several fragments, were identified ( Fig. 12 ). The largest caudal centrum preserves part of its neural arch. The size of the preserved centra compared with that of the sacral centra and the morphology of the neurapophyseal system, which displays an incipient triangular transverse process, suggests that these centra represent proximal caudal vertebrae. By comparison with Camarasaurus ( Osborn & Mook, 1921) and taking into account the presence of two isolated neural arches ( Fig. 12F–K ) that are more proximal than the preserved centra (i.e. placed more dorsally and with more pronounced triangular transverse processes), these centra occupy positions between 3 and 8 in the caudal series. The three centra have concave cranial articular surfaces and flat caudal surfaces. The caudal face becomes slightly concave in the centre such as in Tastavinsaurus (Royo-Torres, 2009) . In general, the centra are craniocaudally short (the ratio between the length and height of the centrum is ≈ 0.58). The centra are slightly transversely constricted at midlength. In cranial and caudal views, the centra are subcircular, narrowing ventrally. Their ventral faces have a slight mediolateral concavity, bordered by smooth crests located at a break of the slope between ventral and medial faces. The lateral faces present neither pleurocoels nor foramina. The transverse processes are laterally projected. The most proximal transverse process found in situ (MG4956) bears a distal expansion that is not observed in more caudal isolated available transverse processes (MG30388).

The neural arches are cranially displaced and occupy a large part of the dorsal face of the centrum. The bases of the arches are craniodorsally projected, exceeding the cranial limit of the centrum. In the most proximal caudal centrum, the transverse processes reach the lateral face of the neural arches through a triangular process very similar to the triangular process of Camarasaurus ( Osborn & Mook, 1921) ; this process tends to be shallower in more caudal proximal centra. The base of the neural arches is one-third the height of the centrum and encloses a neural canal with a circular cross-section. Distally, the prezygapophyses exceed the level of the cranial articular surface of the centrum. Above and between the prezygapophysis there is an unusually small, circular, deep and well-limited spinoprezygapophyseal fossa (sprf) that is considered an autapomorphy of Lourinhasaurus alenquerensis ( Fig. 12A, G ) but has also been described in Jobaria ( Sereno et al., 1999) . The hyposphene ridge, which is slightly fractured, is developed above the neural canal. The prezygapophyses are connected to the centrum by a stout structure (cprl) that borders medially the subrectangular prezygapophyseal centrodiapophyseal fossa (prcdf)). This fossa is limited by the lateral margin of the triangular process (probably homologous to the centrodiapophyseal lamina), which emerges dorsally from a knob present in the lateral face of the neural spine.

The most cranial neural spine bears a significant degree of sacralization, suggesting a more cranial position in the series and the possibility that it may be a caudosacral spine ( Fig. 12J, K ). Nevertheless, it is considered a caudal neural spine because of its overall morphology, the presence of an incipient knob-like process in the lateral face of the base of the neural spine that can be related to other caudal transverse processes with short dorsal bars, and the caudal deflection of the dorsal spine edge. The presence of dorsal bars in the two isolated neural spines suggests the existence of a marked triangular transverse process, at least up to the two first caudal vertebrae.

These two neural spines are robust; the ratio of the height of the most complete neural spine to that of the preserved proximal caudal centra is less than 2. The distal parts of the spines are more expanded transversely than craniocaudally. In cranial view, the most proximal neural spine shows a rounded dorsal margin, while the other has a fan-shaped dorsal margin. The dorsal surface of the most proximal caudal spine slopes cranially, transiting continuously to the cranial face of the spine, and its caudal edge produces a transverse hook-like process in lateral view ( Fig. 12K ). This feature is not observed in the other preserved spine, which exhibits a straight dorsal edge in lateral view; thus, it is considered a possible autapomorphy. The neural spines display deep spinopostzygapophyseal fossae (spof) that occupy their entire caudal faces. The fossa is bordered by two thick and deep spinopostzygapophyseal laminae (spol) that expand ventrally, giving place to the postzygapophyses, which are not well preserved. The cranial faces of both spines are marked by wide prespinal processes with rough and striated surfaces. These prespinal processes are bordered by grooves and crests that are reminiscent of the sprl.

The most cranial spine shows a more complex structure in the dorsal sector of its transverse process; a smooth spinodiapophyseal lamina (spdl) and a probable prezygodiapophyseal lamima (prdl) emerge from the dorsal bar. These laminae limit a small and smooth spinodiapophyseal fossa (sdf). Between the spdl and the spol there is a smooth fossa, a subtriangular to subrectangular postzygapophyseal spinodiapophyseal fossa (posdf) that disappears toward the dorsal area. This fossa is bordered ventrally by a marked, arched, short centropostzygapophyseal lamina (cpol) that in lateral view marks a circular recess that is not present on the left side. Medially to this lamina, a small circular fossa is present.

Chevrons: Only a few distal and proximal fragments of chevron were identified in the sample ( Fig. 12D, E ). It is possible to recognize the absence of a bridge connecting the proximal ends, at least, in the middle

chevrons. The proximal facet has an elliptical outline with a medial process.

APPENDICULAR SKELETON

Left and right scapulae: The complete left scapula and the proximal part of the right scapula are preserved ( Fig. 13A, D, E ). This element is laterally convex and has a significant expanded acromion process that is twice the maximum height of the scapular blade. This process is thicker at its ventral edge (in the glenoid) and becomes thinner craniodorsally. In lateral view, the acromion process has a semicircular to subrectangular outline with a straight caudodorsal edge. The acromial ridge close to the acromion caudal margin has a dorsoventral orientation and deflects cranioventrally, becoming less pronounced towards the ventral margin. Caudal to the acromial ridge, the surface of the acromion process is concave. The scapular fossa has a dorsoventral elliptical outline and occupies nearly two-thirds of the acromion process. The proximal surface, facing cranially, is rough and bears a lenticular to ‘D’-shaped crosssection with a straight lateral edge ( Fig. 13E ). Above the glenoid, it is possible to identify a concavity in the proximal surface that corresponds to the indentation between the scapula and the coracoids. The glenoid faces ventrally. In the ventral margin of the scapular blade, near the acromion process, there is a protuberance ( Fig. 13A, D ) from which a rough crest departs, giving a slightly acute profile to the ventral margin. The lateral side of this crest is bordered by a groove. The scapular blade is expanded distally. This expansion is subquadrangular and bears a distoventral hook-like protuberance. Its distal surface is rough. The scapular blade is thicker near its ventral edge, resulting in a D-shaped cross-section. The lateral face of the scapular blade is slightly convex craniocaudally and strongly convex dorsoventrally, and the medial surface is flat to concave.

Left and right coracoids: The left and the right coracoids were found in anatomical connection with their respective scapulae ( Fig. 13A–C ). Currently it is not possible to reconstruct the dorsal margin of any of them, but they had a subquadrangular outline, as can be interpreted from the photographic record of the Lourinhasaurus excavation ( Lapparent & Zbyszewski, 1957: plate VI, fig. 2). The cranial edge of both coracoids is convex in lateral view and the dorsal margin of coracoids does not surpass the dorsal margin of the scapula. The coracoids are dorsolaterally elongated and thicker at the glenoid sector, producing a concave surface on both sides of the coracoids. The glenoid is thick and laterally projected ( Fig. 13C ) bearing a rough, flat and sigmoid facet, facing ventrally. Cranial to the glenoid, there is a circular recess of the coracoid ventral margin. Between the glenoid and the coracoidal foramen, the caudal margin bears a concavity corresponding to the attachment area for the scapula. The coracoidal foramen is elliptical, elongated craniocaudally and with a caudomedial development.

Sternal plates: In the sample are two sternal plates ( Fig. 14 ) not referred to by Lapparent & Zbyszewski (1957). These two elements have a similar mediolateral width and probably correspond to the right and left sternal plates. The left one could correspond to a cranial sector of the sternal plate and the right one to the caudal sector. With both fragments it is possible to infer a craniocaudally elongated oval outline for the complete sternal plate. In ventral view, the medial margin is convex and the lateral margin is straight to slightly concave. In the medial edge of the right sternal plate (MG30382) it is possible to observe the zone of articulation between both sternal plates. The region for the attachment of sternal ribs is not preserved. The sternal plates become thicker near the lateral and cranial margin. These plate-like elements are dorsally concave and ventrally convex. The axis of this convexity is close to the lateral margin. In the surface of these bones there is a particular bone texture formed by cross-linked fibres. The margins of these plates are rough. Cranially it is possible to identify a triangular phalanx-like process.

Left and right humeri: The humerus is slightly curved, with a convexity caudal and laterally directed ( Fig. 15A–E ). The diaphysis has an elliptical crosssection, craniocaudally compressed. The proximal section is strongly expanded mediolaterally with proximal, lateral, and medial margins cranially projected producing a wide and deep teardrop-shaped depression. The cranial face of the proximal section bears a small circular depression near the proximal margin. The humeral head is proximomedially projected. The proximolateral corner is rounded. A deltopectoral crest runs along the lateral edge of the humerus from the proximal margin up to its midlength. This crest is craniolaterally projected and its transverse outline is subrectangular. The proximal surface is rough and the humeral head occupies two-thirds of this surface (with an oval to elliptical proximal outline). The distal portion of the left humerus is well preserved (but covered with plaster) and some fragments of the right humerus distal section were also identified. The distal section has a slight mediolateral expansion (corresponding to two-thirds of the proximal portion of the mediolateral expansion). The cranial and caudal faces of the distal region are flat and flat-to-concave, respectively. The craniolateral sector of the distal region bears two rough protuberances. The distal surface is flat and rough and the ulnar and radial condyles are not separated by a marked intercondylar groove. The radial condyle is more expanded and polygonal than the ulnar condyle. The humerus/femur length ratio is 0.82.

Left radius: The radius ( Fig. 16A–E ) is cylindrical and arched longitudinally with its convexity cranially orientated. The proximal portion is expanded in a craniomedial-to-caudolateral direction, and its cranial margin exhibits an acute profile. Parting from the cranial edge of the proximal surface is a crest that disappears distally and is replaced by another more medial crest. The latter crest ends in a triangular facet. In proximal view, the outline of the proximal surface is elliptical, with a concave and rough surface ( Fig. 16A ). The diaphysis is compressed craniolaterally to caudomedially. In the caudal face, from the diaphysis towards the distal portion, there is a proximodistal groove bordered by two crests. In distal view, this groove has a semicircular outline with a straight cranial margin; it has a rough and convex surface.

Left ulna: The left ulna is preserved and is associated with the left radius ( Fig. 16A–E ). In proximal view, the ulna has a triradiate outline ( Fig. 16A ) composed of three vertices: (1) a craniolateral process (distal sector slightly damaged), (2) a cranial process (distally damaged), and (3) a rounded caudal apex. Although partially broken, the cranial process is longer and more robust than the craniolateral process. This triradiate outline extends to the midlength of the ulna. The proximal surface is convex with its highest point located on its centre. The surfaces of the cranial and craniolateral processes are flat and present straight profiles in medial and caudolateral views. The ulnar shaft has an oval-to-circular transverse section. On the cranial face of the ulnar shaft, there is a proximodistal crest that extends distally to the vertex of a triangular facet, the distal portion of which projects slightly toward the medial side. The distal surface of the ulna is rough and convex with an oval outline elongated mediolaterally and has an acute margin on the craniomedial side.

Carpal II: The carpus is poorly known in sauropods ( Upchurch et al., 2004) and the interpretation was based in some previous occurrences (e.g. Osborn, 1904; Ostrom & McIntosh, 1966; Bonnan, 2003; Royo-Torres et al., 2006; R. Royo-Torres, pers. observ., 2013). The element MG30385 is considered as carpal II ( Fig. 17 ). Lapparent & Zbyszewski (1957) noted the existence of a carpal II in Lourinhasaurus , but it was never described before and probably corresponds to the same bone. This element is blockshaped, with a flat proximal surface which could be interpreted as the area for reception of the distal portion of the ulna and a concave distal surface. The putative distal surface, with a D-shaped outline in proximal view, bears a central circular process that could be considered an autapomorphy of Lourinhasaurus alenquerensis ( Fig. 17D, E ).

Left ilium: The outline of the iliac blade is semicircular ( Fig. 18 ). The lateral face of the ilium cannot be described because is in exhibition and covered by a plaster platform. The iliac blade is vertical with a slight medial slope and has a convex dorsal margin that becomes straight toward the postacetabular process. The preacetabular process is thick, craniolaterally orientated and has a subtriangular outline in medial view. The postacetabular process is caudally orientated, and the chord through the ischiatic and pubic articulations passes through the ventral margin of the postacetabular process. This combination is considered an autapomorphy of Lourinhasaurus alenquerensis . The medial surface of the ilium, corresponding to the area of attachment of the sacral ribs, has a few dorsoventral crests that reach the dorsal margin of the iliac blade. In the ventral margin of the postacetabular process there is a rough and oval craniocaudal crest, a feature that is considered an autapomorphy of Lourinhasaurus alenquerensis ( Fig. 18B ). A strong pubic peduncle is laterally expanded and subrectangular in cranial view with a convex-to-acute cranial surface. The caudal surface of this peduncle is markedly concave, and the outline of its distal surface is semicircular to teardrop-shaped. The ischiatic peduncle is weakly developed and laterally orientated. In the base of the pubic peduncle, an oval protuberance is observed.

Left and right pubis: The two pubis of the type individual were recovered ( Fig. 19 ). The iliac peduncle is dorsally projected and radially expanded with a rough and flat surface and a heart-shaped to elliptical outline in proximal view ( Fig. 19C ). The semicircular acetabulum is an individualized and well-marked surface that is distinguishable from the iliac and ischiatic peduncles. The obturator foramen is closed and has an elliptical outline that is craniocaudally elongated. The pubic blade lies in the same plane as the proximal plate and has a teardrop-shaped crosssection. The pubic blade has the same orientation as the ischiatic peduncle (i.e. they are parallel), a feature that is considered an autapomorphy of this taxon ( Fig. 19A ). In caudal view below the ischiatic peduncle, the pubic blade becomes thinner and deflects medially, producing a caudal margin with an s-shaped profile ( Fig. 19B ). The cranial edge of the iliac peduncle is flat and bears a triangular striated facet. The distal part of the pubis is expanded, forming an oval, rough, convex tip. The distal part of the pubic blade has a mediocranial expansion and displays a hookshaped profile in lateral view resulting from the dorsal projection of the cranial tip.

Left and right ischia: The two ischia are preserved but slightly fractured in the ventral margin of the proximal plate ( Fig. 20 ). The iliac peduncle is oval, is compressed mediolaterally (more pronounced on the right ischium), and has a convex and rough surface. The pubic peduncle has an arched profile in lateral view; in cranial view it presents a rough surface with a subrectangular outline where its width decreases ventrally. This surface has, at midlength, a lip-like structure on its lateral edge. The two peduncles are separated by a deep and well-differentiated acetabulum. The lateral edges of this surface are uplifted, producing a crest that is caudally flanked by a marked groove. The presence of this crest is considered an autapomorphy of Lourinhasaurus alenquerensis ( Fig. 20C, E ). The ischiatic blade twists nears its distal end and the ischiatic blades become almost co-planar. The distal symphysis is short and has a teardrop outline. Near the pubic peduncle, the ventral margin of the ischiatic proximal plate has a v-shaped symphysis. The cross-section of the ischiatic blade has a teardrop outline with an acute ventral edge (the ventral margin bears a longitudinal crest). The angle between the ischiatic blade and the pubic peduncle is approximately 80° (the long axis of the blade passes through the pubic peduncle). On its lateral face near its dorsal margin and close to the proximal plate, the ischiatic blade bears a small tuberculum (50 mm) bordered by a parallel groove. The medial face of the ischiatic blade also bears a proximodistal crest that runs through it from its dorsal (proximal) to its ventral (distal) edge. The distal part of the ischium is slightly expanded; in distal view, it shows a subrectangular arched outline with a concavity facing dorsally. The distal surface is flat and rough ( Fig. 20B ).

Left femur: The femur is straight and craniocaudally compressed, resulting in an elliptical cross-section (craniocaudal/mediolateral length ratio: 0.58). The femoral shaft shows a marked medial deflection without a lateral bulge ( Fig. 21A, B ), a unique combination in sauropods (see explanation in fibula description). In the femur of Lourinhasaurus , the diaphysis makes an angle of approximately 10° with the vertical axis when the distal condyles are situated in the horizontal plane ( Fig. 21B ). Proximally, on the lateral face of the femur, there is a shallow crest at the location of the lesser trochanter. The femoral head, being medially wide, is slightly proximomedially projected. The 4th trochanter is elongated proximodistally and located at the medial edge of the femoral caudal face. Its distal tip is situated at midshaft. The 4th trochanter is bordered laterally by a proximodistal elliptical concavity and medially by a wide and smooth concavity. The proximal surface of the femur is rough and is lacking part of the femoral head cranial edge ( Fig. 21C ). The distal part of the femur becomes larger medially and laterally, bearing the tibial and the fibular condyles with convex and rough proximal surfaces. The tibial condyle is caudally projected; in caudal view, it presents a subtriangular outline that is lateromedially compressed. The distal outline of the fibular condyle is more polygonal than the outline of the elliptical tibial condyle ( Fig. 21D ). On the caudal surface of the tibial distal section, there is a deep intercondylar groove that continues to the caudal surface. The cranial face of the distal section is smoothly concave, and the condyles are not present in this region.

Left tibia: The tibial diaphysis is straight and has an elliptical to subcircular cross-section (craniolaterally to caudomedially elongated) ( Fig. 22A–D ). The proximal portion, which has a slightly fractured lateral margin of the proximal section (the proximal sector of the fibular articulation) does not permit testing for the presence of a projected edge (‘second cnemial crest’ sensu Bonaparte, Heinrich & Wild, 2000), a feature that is present in other sauropods ( Mannion et al., 2013). The expansion of the distal section is less pronounced than the proximal expansion and, in distal view, it is subrectangular and slightly compressed transversally. The posteroventral process is suboval, craniocaudally elongated and separated from the articular surface for the ascending process by a groove with a subcircular outline ( Fig. 22D ). This groove is evident on the caudal face of the distal section. The distal surface of the posteroventral process and the articular surface for the ascending process tibia are rough and convex. The ratio between tibia and femur lengths is 0.65.

edge, is expanded, and the craniocaudal diameter of the proximal end is only 8% greater than its transverse diameter ( Fig. 22C ). The proximal surface is rough and flat to concave. At the cranial margin of the proximal section stands the subtriangular cnemial crest, which is laterally projected (the vertex of this crest also has a lateral orientation). The fibular articulation is well defined and bears a rough surface. It is separated from the cnemial crest by a proximodistal groove. The preservation of the lateral Left fibula: The fibula has a general incipient sigmoid form; it is almost straight, with expanded proximal and distal ends ( Fig. 22E–J ). In cranial view ( Fig. 22G ), the fibula shows a generally straight profile with a slight laterocaudal deflection of its proximal portion at the level of the lateral trochanter. The lateral trochanter presents a proximodistal development and a sigmoid shape, with its distal tip directed toward the shaft caudal margin. In lateral view, the proximal and distal edges are straight and semicircular, respectively ( Fig. 22I, J ). The anterior trochanter is placed at the proximal third of the fibula. It is rounded and proximodistally elongated; it is craniomedially directed and does not produce a crest-like structure. The proximal sector of this trochanter is absent. The medial face of the proximal section is flat and somewhat eroded. Despite this erosion, it is possible to recognize the limits of the triangular tibial articular surface with its distal tip above the apex of the anterior trochanter ( Fig. 22H ). In cross-section, the fibular shaft is elliptical (elongated craniocaudally). In proximal view ( Fig. 22E ), the fibula is subrectangular (fractured cranially) and slightly arched, with its convexity orientated laterally. The distal surface is convex and has a transverse semicircular outline ( Fig. 22F ). The medial face of the distal section is medially projected and bears a proximodistal groove. The tibia and the fibula are of equal length, implying a more distal position of the fibula relative to the tibia for the reception of the astragalus, a feature considered an autapomorphy of Lourinhasaurus alenquerensis . In sauropods, the fibula is generally taller than the tibia because it has an area for the reception of the lateral face of the astragalus. Nevertheless, in Lourinhasaurus alenquerensis , the tibia and fibula are similar in height and when the proximal sections of both elements are at the same level, the astragalar articular face of the fibula are at the same level as the tibial distal section, and cannot articulate with the astragalus. This could be related to the medial deflection of the femur shaft described above. If the femur shaft is in vertical position, the fibular condyle occupies a more distal position than the tibial condyle, resulting in a more distal position of the fibula relative to the tibia. With a more distal position of the fibula, the astragalar articulation face could articulate with the lateral face of the astragalus.

Left astragalus: The available astragalus is a robust element, fragmented at its medial edge ( Fig. 23 ). The distal face is rough and transversally convex ( Fig. 23C ). In cranial view, it has a wedge-shaped format (higher at the lateral edge). By contrast, in lateral view, the astragalus bears a semicircular outline and has subcircular concavity (= fibula articular surface) ( Fig. 23B ). The posterior astragalar fossa slopes caudally. In this fossa there is a deep and circular foramen ( Fig. 23D ) that pierces the concave caudal surface of the ascending process. The ascending process of the astragalus is broken caudally, and it is thus impossible to interpret if this process reaches the caudal edge of thge astragalus. In distal view, just behind the caudomedial edge of the ascending process, the caudal margin becomes slightly acute. Parting from the caudomedial corner of the ascending process is a crest that borders medially the circular foramen referred to above and subdivides the posterior astragalar fossa.

Right pedal (?) phalanx II: Besides the reference to a manual phalanx found from Moinho do Carmo quarry ( Lapparent & Zbyszewski, 1957), we considered this phalanx more similar to pedal phalanges, probably a pedal phalanx II ( Fig. 24 ). This phalanx (ventral face strongly damaged) has a proximodistal/mediolateral width ratio close to 1. Along its proximodistal length the phalanx are lateromedially constricted. The lateral edge is shorter proximodistally than the medial edge. The proximal surface is slightly concave, smooth and with some grooves. In proximal view, the dorsal edge of this surface bears a concavity that has small expression in the proximal sector of the phalanx dorsal surface. The distal surface is probably convex, but the preservation does not allow describing it in detail.

Figures

Figure 2. A, geological map (adapted from Oliveira et al., 1992) showing the Portuguese Mesozoic levels. B, geological map of the Alenquer region (adapted from Leinfelder & Wilson, 1989) with the location of the Moinho do Carmo site. C, stratigraphy of Arruda sub-basin sensu Kullberg et al. (2006) (*sensu Schneider et al., 2009, 2010); CHR, chronostratigraphy. D, Moinho do Carmo quarry map (adapted from Lapparent & Zbyszewski, 1957) and its interpretation: 1, scapulae girdle; 2, left humerus; 3, left radius and ulna; 4, cranial-to-middle dorsal vertebrae (DV1 to DV5); 5, right humerus; 6, sternal plates (?); 7, middle dorsal-to-sacral vertebrae (DV7 to DV12 and the sacral centra); 8 and 9, proximal caudal vertebrae; 10, left femur; 11, left tibia, fibula and astragalus; 12, ischia; 13, pubis; 14, left ilium; 15, middle dorsal vertebrae (DV6).

Figure 3. Cervical vertebrae of L. alenquerensis. Cranialto-middle cervical centrum (MG30377) in right view (A) and its schematic interpretation (B); middle-to caudal cervical centrum (MG30373) in left (C) and ventral (D) view. Traced line: broken borders; fill in traced pinstripes: broken or eroded areas.

Figure 4. Partial neural arch of caudal cervical vertebra of L. alenquerensis (MG30379) in cranial (A), right lateral (B), and caudal (C) views and their respective interpretations (D, E, F). Traced line: broken borders; fill in traced pinstripes: broken or eroded areas.

Figure 5. Dorsal vertebrae series of L. alenquerensis (MG4956 and MG30378) in left (first and third lines) and ventral (second and fourth lines) views.

Figure 6. Caudal dorsal vertebrae DV10 (MG4956) of L. alenquerensis in caudal (A) and cranial (B) views and its schematic figuration (C) showing the circular depression on the cranial articular surface. Ventral surface of the cranial dorsal vertebra DV3 (MG4956) bearing its ventral concavity (D), an autapomorphy of L. alenquerensis. Traced line: broken borders.

Figure 7. Change in the pneumaticity along the dorsal series of L. alenquerensis. Lateral view of the dorsal series (A) and the cross-section of DV2, DV8, and DV12 (B, without scale). The traced line indicates lost bone.

Figure 8. Middle neural spine of L. alenquerensis (probably from the 6th or 7th dorsal vertebra, MG30384) in cranial view (A) and its schematic interpretation (B); and in right view (C) and its schematic interpretation (D). Neural arch of L. alenquerensis DV6 in left view (E) and its schematic interpretation (F). Traced line, broken borders; fill in traced pinstripes, broken or eroded areas. G, Camararasaurus dorsal vertebrae (Osborn & Mook, 1921: pl. LXX) with boxes indicating the relative position of the figured Lourinhasaurus neural arch fragments.

Figure 9. Fragment of a middle neural spine of L. alenquerensis in cranial (A) and caudal (B) views.

Figure 10. Dorsal rib of L. alenquerensis (MG30370). Proximal section of a caudal dorsal rib in caudal (A) and cranial (B) view; and the cross-section of a proximal-to-middle sector of cranial dorsal rib (C).

Figure 11. Sacral remains of L. alenquerensis. Sacral centra (MG4956) in left view (A) and its schematic interpretation (B). Sacral neural spines (MG30376): left view (C) and the most caudal available sacral spine in cranial view (D) with its schematic interpretation (E), and caudal view (F).

Figure 12. Proximal caudal vertebrae of L. alenquerensis. Proximal caudal centra (MG4956) in cranial (A), left (B), and caudal (C) views. Middle chevron articulation of L. alenquerensis (MG30387) in caudal (D) and cranial (E) views. Two proximal caudal neural spines (MG30374) in cranial (F and J), caudal (G and I) and left (H and K) views. Traced line: broken borders; fill in traced pinstripes: broken or eroded areas.

Figure 13. Scapular girdle of L. alenquerensis. Left scapula and coracoid (MG5780) in lateral view, right scapula (MG30371) in medial (D, black line: cross section of scapular blade) and proximal (E) views and right coracoid (MG 30372) in lateral (B) and ventral (C) views.

Figure 14. Sternal plates of L. alenquerensis. Right (MG30382) (A) and left (MG30383) (B) sternal plates in ventral view and the cross-section of the right one (C). The traced line indicates lost bone.

Figure 15. Forelimb of L. alenquerensis. Left humerus (MG2) in caudal (A), cranial (B), lateral (C), medial (D), and proximal (E) views. The traced line indicates lost bone.

Figure 16. Left radius and ulna (MG4979) in proximal (A), lateral (B), cranial (D), caudal (E) views, and the outline of the distal view (C). Traced line: broken borders.

Figure 17. Carpal II of L. alenquerensis (MG30385) in medial? (A), lateral? (B), cranial? (C), caudal? (D), distal (E), and proximal (F) views.

Figure 18. Left ilium of L. alenquerensis (MG5781) in medial view (A). The base of postacetabular process (poap) in ventral view (left) noted in a schematic figuration of the ilium (right) (B). Traced line: broken borders or superimposing bone.

Figure 19. Left pubis of L. alenquerensis (MG 4970) in lateral (A), caudal (B), and proximal (C) views.

Figure 20. Ischia of L. alenquerensis (MG4957). Left ischium in distal (B), lateral (C) and cranial (D) views, and right ischium in medial (A) and lateral (E) views.

Figure 21. Left femur of L. alenquerensis (MG4931) in caudal (A) and proximal (C) views, and the outline of distal view (D). Outline of L. alenquerensis femur without scale, showing the marked medial deflection of the femur shaft when the tibial and fibular condyles are in the horizontal plane (B). Traced line: broken borders.

Figure 22. Left tibia (MG4983) and fibula (MG4984) of L. alenquerensis. Tibia in lateral (A), cranial (B), and proximal (C) views, and the outline of distal view (D). Fibula in proximal (E), cranial (G), medial (H), and lateral (I) views, schematic interpretation of lateral view (J) and the outline of its distal view (F). Traced line: broken borders.

Figure 23. Left astragalus of L. alenquerensis (MG30375) in medial (A), lateral (B), ventral (C), and dorsal (D) views.

Figure 24. Right pedal (?) phalange II of L. alenquerensis (MG30386) in dorsal (A), lateral (B), and proximal (C) views.