In June 1949 a partial skeleton of a large sauropod, found by American geologist Harold Weston Robbins, was excavated in a locality near Alenquer.

It was discovered in layers of the Praia da Amoreira-Porto Novo Member of the Lourinhã Formation, dated from the late Kimmeridgian, and therefore slightly older than the Moinho do Carmo specimen.The skeleton is composed of nine neural spines, 12 complete posterior cervical and dorsal vertebrae, 12 dorsal ribs from both sides of the animal and other fragmentary material from the appendicular skeleton.

[6] In 2014, Mocho and colleagues published a complete re-description of the Moinho do Carmo specimen, including elements never described before, and also provided a phylogenetic revision of Lourinhasaurus.

[2] The higher humerus/femur length ratio of Lourinhasaurus, pointed by John Stanton McIntosh, might've suggested a slightly more verticalized posture compared to Camarasaurus.

[14] Notably, John Stanton McIntosh in 1990 proposed for the first time that the Moinho do Carmo specimen represented a new species with close affinity to Camarasaurus.

[9][10][11] McIntosh later suggested the possibility that the skeleton might represent its own genus, based on the higher humerus/femur length ratio compared to Camarasaurus.

The phylogenetic hypotheses proposed by that work suggest that Lourinhasaurus is a basal member of the Macronaria closely related to Camarasaurus, in agreement with McIntosh's earlier views.

[2]Jobaria tiguidensis Haplocanthosaurus Rebbachisaurus garasbae Limaysaurus Nigersaurus taqueti Amargasaurus cazaui Dicraeosaurus Apatosaurus Diplodocus Barosaurus lentus Tehuelchesaurus benitezii Lourinhasaurus alenquerensis Camarasaurus Giraffatitan brancai Phuwiangosaurus sirindhornae Euhelopus zdanskyi Venenosaurus dicrocei Cedarosaurus weiskopfae Tastavinsaurus sanzi Titanosauria Mocho et al. 2014 strict consensus cladogram obtained from Wilson’s (2002) data matrix.