Your Friends The Titanosaurs, part 15: Lirainosaurus, Lohuecotitan, and Loricosaurus

This and the next few posts are going to be spending significant time outside of the South American titanosaur stronghold. Only Loricosaurus scutatus will be representing South America this time, with the other two slots filled by the unusually small Lirainosaurus astibiae and larger Lohuecotitan pandafilandi, both from the Upper Cretaceous of Spain.

This map, part of Figure 1 from Díez Díaz et al. (2011), shows the distribution of European titanosaur cranial material, but also happens to show the discovery locations of Lirainosaurus astibiae, Lohuecotitan pandafilandi (Lo Hueco), and species assigned to Magyarosaurus, which is coming up quickly. CC-BY-4.0.

Lirainosaurus astibiae

Lirainosaurus astibiae is one of the best-represented and certainly most thoroughly described titanosaurs. Aside from the original description (Sanz et al. 1999), there are also publications devoted to its bone histology (Company 2011; albeit referred material), the braincase (Díez Díaz et al. 2011), the teeth (Díez Díaz et al. 2012), the axial skeleton (Díez Díaz et al. 2013a), the appendicular skeleton and osteoderms (Díez Díaz et al. 2013b), and the tail alone (Vidal and Díez Díaz 2017), along with additional records (Company et al. 2009; Díez Díaz et al. 2015) and an entire dissertation (Díez Díaz 2013). It also shows up in just about every publication on European titanosaurs in general.

Despite our exhaustive knowledge of this animal, it's not notably familiar outside of research circles. Even there, it's oddly under-represented in recent phylogenetic analyses (6 out of 22 checked for 2015 to 2019), in which it tends to show up as a moderately derived to very derived lithostrotian. (Díez Díaz et al. 2018 give it its own lithostrotian clade, Lirainosaurinae, with Ampelosaurus and Atsinganosaurus.) Argentinosaurus huinculensis, known from far fewer bones and with basically one anatomical description under its ample belt, turns up in 15 of those papers. While I can't speak to its relative lack of popularity in phylogenetics, its low public visibility probably has to do with the lack of a well-publicized "hook", such as a "first", a "biggest", a "smallest", some odd anatomical feature, etc. I say "well-publicized", because apparently it's not widely appreciated just how small L. astibiae was. (Maybe it's because Magyarosaurus got there first.)

L. astibiae was described 20 years ago, in Sanz et al. (1999), which actually makes it fairly "old" for a titanosaur. The original material was found at the Laño quarry, a sand quarry between Laño and Albaina in Condado de Treviño, Castile and Leon, north-central Spain (Díez Díaz et al. 2015). The geologic unit of interest has been described under various names, and apparently lacks a formal name; the Paleobiology Database calls it the Vitoria Formation, which is a bit odd because no primary source seems to do so. We *can* say, though, that L. astibiae fossils are found in three horizons of the unit at the Laño quarry (Sanz et al. 1999), and it dates to the latest Campanian (Corral et al. 2016). Some 3,500 macrofossils were recovered from the Laño quarry between 1988 and 1997, of which about 150 fossils can be assigned to L. astibiae. Among the haul were multiple braincases, scapulae, coracoids, humeri, ilia, femora, tibiae, and fibulae, indicating at least five L. astibiae individuals (two in L1A, two in L1B, and one in L2) (Díez Díaz et al. 2015).

L. astibiae pectoral bones, Figure 2 in Díez Díaz et al. (2013b) (see for full caption). CC-BY-4.0.

The genus name is derived from the Basque "lirain", meaning "slender", and the species name honors Dr. Humberto Astibia, who led the work at Laño (Sanz et al. 1999). This gives us "Humberto Astibia's slender lizard." The holotype is a first? caudal vertebra, MCNA 7458, at the time of description "provisionally kept" at the Museo de Ciencias Naturales de Alava, Vitoria-Gasteiz, Spain (Sanz et al. 1999). With everything from Laño, it is possible to build up a pretty good picture of the animal's proportions and anatomy from the shoulders back; missing parts include much of the skull, the mandible, most of the neck, the radius, the hands, the ischium, the sacrum, and most of the feet. The site is interpreted as a braided river in an alluvial system (Díez Díaz et al. 2013a), which presumably has something to do with the rarity or absence of small parts such as chevrons and hand and foot bones.

The two known braincases appear to have come from subadults, based on incomplete fusion of bones (Díez Díaz et al. 2011). Teeth assigned to L. astibiae appear to change from juveniles to adults, beginning as fairly simple small cylinders (<13 mm crown height, or about 0.5 in) with smooth enamel, and ending up tapered with more ornamented enamel. The changes may indicate feeding differences between juveniles and adults (Díez Díaz et al. 2012). Concerning the axial skeleton, one cervical centrum, 13 dorsal vertebrae, and 40 caudals have been found, along with four dorsal ribs and one chevron. The cervical doesn't reveal too much, but is relatively long at 18 cm (7 in), heavily pneumatized, and apparently opisthocoelous. The dorsals are mostly represented by centra or neural arches, and again are heavily pneumatized and opisthocoelous. Caudals are pneumatized, but not as strongly as in saltasaurs, and are typically procoelous transitioning to amphiplatyan, with the neural arches on the anterior part of the centra. Ribs are also pneumatic (Díez Díaz et al. 2013a). Vidal and Díez Díaz (2017) made a 3D reconstruction of the first 20 vertebrae of the tail and found they could produce a moderate upward bend (42 degrees), somewhat more of a downward curve (57.5 degrees), and close to a half-circle bend laterally. The neutral position was slightly inclined downward.

Concerning the appendicular skeleton, multiples of most of the large bones are known from Laño. There are some accessory ridges on the shoulder and pectoral bones that appear to be diagnostic, and the largest scapula is 72.2 cm long (28.4 in) (Díez Díaz et al. 2013b). The limb bones are noted for their gracility; Sanz et al. (1999) regarded the femur as among the most slender in Sauropoda. The largest femur reaches the grandiose length of 81.6 cm (31.2 in), and the largest humerus is estimated at 66 cm long (26 in) (Díez Díaz et al. 2013b). The ilium is only partially known, but is pneumatized (Díez Díaz et al. 2013b), and it appears that the anterior part is expanded, flaring out laterally (Sanz et al. 1999). A couple of chunks of osteoderms are known, perhaps belonging to "roots" of root-and-bulb osteoderms (Díez Díaz et al. 2013b).

L. astibiae long bones of the leg, Figure 5 in Díez Díaz et al. (2013b) (see for full caption). CC-BY-4.0.

In addition to the Laño quarry, another group of fossils from outcrops of the Sierra Perenchiza Formation near Chera in Valencia, Spain, is regarded as Lirainosaurus cf. astibiae (Company et al. 2009; Díez Díaz et al. 2015). The sites are thought to pertain to a freshwater marshy environment . The remains of at least six individual titanosaurs are present at the most productive locality, with another three at three other localities (Díez Díaz et al. 2015). It was originally thought that all of the titanosaurian fossils belonged to one taxon (Company et al. 2009; Company 2011), but it now appears that there are two taxa in the material (Díez Díaz et al. 2015). Ortega and Pérez-García (2009) assigned a caudal from Sacedón, Guadalajara, to cf. Lirainosaurus sp., but Díez Díaz et al. (2015) considered this indeterminate. Several femora from southern France potentially belong to Lirainosaurus astibiae, one of which had been misidentified as belonging to Rhabdodon by Lapparent, which gives you an idea of the size we're dealing with (Vila et al. 2012). Díez Díaz et al. (2013b) noted that these bones differed from L. astibiae in several features, though.

So, about the size. We've already seen from the cited measurements that L. astibiae was not particularly large. Based on the Laño sample, Díez Díaz et al. (2013b) suggested adult individuals had a range of 4 to 6 m for length (13 to 20 ft) and 2 to 4 metric tons for mass (2.2 to 4.4 US tons), which seems a bit heavy for a gracile-limbed and heavily pneumatized animal with a significant neck and tail, but there you go. That's a toy sauropod. That's the length of a large Camptosaurus. We're talking about a sauropod that could hide in a corn field if it kept its head down, one you could put on a leash and take for a walk without feeling absurdly dwarfed. (There is a downside, though. Because L. astibiae is so much closer to human scale than some 30-meter, 50-ton flesh barge of a super-titanosaur, if it decides it doesn't like you, it can be a lot more direct about letting you know.) Why should L. astibiae be so small? Spain and southern France were a large island at the time (the Ibero-Armorican Island or Domain), but the landmass was plenty large enough to support 15-m-long Ampelosaurus atacis. Presumably L. astibiae found a niche that could be filled by a toy sauropod instead of one of the contemporaneous ornithopods, similar to the diminutive saltasaurs of South America, but what that was isn't clear yet.

Lohuecotitan pandafilandi

Lohuecotitan pandafilandi is another titanosaur of recent vintage, having been described in Díez Díaz et al. (2016). The genus name refers to the Lo Hueco site in Spain, and the species name is a reference to Pandafilando de la Fosca Vista ("Panphilanderer of the Menacing Gaze"), a fictional giant in "The Ingenious Gentleman Don Quixote of La Mancha" (by which I mean the giant is a hoax within the book). This gives us something like "Pandafilando's titan from Lo Hueco".

As noted, L. pandafilandi was found at the Lo Hueco fossil site. This locality is near Fuentes, in the province of Cuenca in Castilla–La Mancha (providing another link to Don Quixote), east-central Spain. The bones are from the upper Villaba de la Sierra Formation, deposited in the late Campanian–early Maastrichtian time frame of the Late Cretaceous. The Lo Hueco site, discovered in 2007, is interpreted as a muddy floodplain near the coast, and crossed by sandy distributary channels. At least two types of titanosaurs are represented, with "multiple partial skeletons in anatomical connection or with a low dispersion of their skeletal elements" (Díez Díaz et al. 2016). Sauropods are reported as the most abundant vertebrates at Lo Hueco, but the site has also yielded fossils of fish, amphibians, turtles, lizards, crocs, and non-sauropod dinosaurs (Díez Díaz et al. 2016).

L. pandafilandi is based on one of these associated skeletons, collectively cataloged as HUE-EC-01 (Lo Hueco collection at the Museo de Paleontología de Castilla–La Mancha in Cuenca, Spain), but with individual elements getting their own numbers (Díez Díaz et al. 2016). It showed up briefly in Díez Díaz et al. (2015) as the "EC1" skeleton. HUE-EC-01 includes three cervical centra, cervical neural arch fragments, six dorsals, sacral fragments and dorsal ligament, 20 caudals, ribs and chevrons, most of the pelvis, the left ulna, the right leg except for the ankle and foot, and indeterminate pieces. Overall, coverage is pretty good; the main sections that aren't represented are the head, shoulder girdle, hands, and feet. It's possible that we do have teeth and braincase remains for L. pandafilandi at the Lo Hueco site, because examples from two different titanosaur taxa are represented, but neither type was found associated with the type L. pandafilandi individual (Díez Díaz et al. 2016). Neither type is Lirainosaurus, either, which shows there were at least three different taxa in Spain near the end of the Cretaceous (Díez Díaz et al. 2015). L. pandafilandi was not as small or gracile as Lirainosaurus, which is not a difficult thing for a sauropod; I estimate from the figures that femur HUE-03108 of L. pandafilandi was about 110 cm long (43 in).

A lifesize model of L. pandafilandi in Fuentes, Cuenca, found on Wikimedia Commons, taken by user PePeEfe. CC-BY-SA-4.0. L. pandafilandi has inspired several lifesize models already; not too shabby for a 2016 naming.

The original phylogenetic analysis by Díez Díaz et al. (2016) found L. pandafilandi to be a basal lithostrotian, which was also found by Díez Díaz et al. (2018), where it paired with Paludititan nalatzensis. On the other hand, Sallam et al. (2018) found it to be a very derived lithostrotian (although in the same neighborhood as Paludititan again), and Gorscak and O'Connor (2019) found it to not only be a very derived lithostrotian, but also nested rather deeply within Lognkosauria in one analysis and paired with Nemegtosaurus mongoliensis in another. (In other words, "situation normal" for titanosaurs.)

Loricosaurus scutatus

"Isn't that just Neuquensaurus?" shouts some wise guy in the back row. That's never been proven, pal, and it's my blog. ("What about Lametasaurus indicus?" shouts some other wise guy. Lametasaurus indicus doesn't count because it's actually a savory dish of many Lameta Formation animals. So there.)

Anyway, Loricosaurus scutatus has already briefly appeared in the series on titanosaur osteoderms. It originated in von Huene's 1929 monograph on the Cretaceous dinosaurs of Argentina. Von Huene described L. scutatus from Cinco Saltos, which has also produced "Titanosaurus" australis (=Neuquensaurus) and the holotype of recent guest Laplatasaurus araukanicus. That should mean the horizon is the Anacleto Formation, as established for Laplatasaurus araukanicus (Gallina and Otero 2015). The genus name is derived from the Latin "lorica", or "body armor", and the species name "scutatus" is a reference to a Roman shield. It's a bit redundant, but it works out to something like "shielded armored lizard". (The mysterious Internet "Loricosaurus noricus" is probably a slip of the pen for Leipsanosaurus noricus, a genuine ankylosaur and one of what feels like a hundred dubious names that are probably synonyms of Struthiosaurus austriacus. Just to confuse things a bit more, there is also a stegosaur named Loricatosaurus.)

The type series consisted of 26 scutes and plates, assigned catalog numbers C.S. 1210, 1213–1215, 1218–1221, 1226, 1228–1232, 1235, 1237, 1470–1477, 2006, and 2010 (Huene 1929; the catalog numbers are also known under MPL-C.S., meaning they are in the Cinco Saltos collection of the Museo de la Plata). If you've got your copy of "The Illustrated Encyclopaedia of Dinosaurs" handy, you can see C.S. 1215 illustrated on page 94 as "Laplatasaurus". The osteoderms are of the "oatmeal cookie" scute variety rather than bulb-and-root using the Vidal et al. (2014) scheme, or the ellipsoidal, cylindrical, and mosaic categories of the D'Emic et al. (2009) scheme. They range from 1.3 to 15 cm in diameter (0.6 to 5.9 in) and 0.5 to 7 cm thick (0.2 to 3 in). The larger examples have prominent longitudinal keels, which von Huene depicted as dorsal but are now interpreted as ventral. Von Huene also reported a rather thin and more sharply edged specimen from near Rancho de Avila, which he assigned to aff. Loricosaurus sp. Armored sauropods not yet being taken seriously, von Huene thought he was looking at a "polacanthid" or "acanthopholid" (not different things; the family names were used interchangeably). In following this idea, he suggested that some additional fossils, a metacarpal from Cinco Saltos (C.S. 1200) and a sacrum, may have come from L. scutatus because they appeared to also be ankylosaurian.

L. scutatus was basically forgotten as a taxon after von Huene's description, even after Bonaparte and Powell (1980) brought respectability to armored sauropods with Saltasaurus loricatus. Bonaparte and Powell were noncommittal on the proper assignment of the L. scutatus osteoderms, suggesting they more likely belonged to Titanosaurus australis or T. robustus (=Neuquensaurus) than to Laplatasaurus, but Powell (1980) suggested they belonged to Laplatasaurus based on size. Powell appears to have later reconsidered, because he did not mention osteoderms when discussing Laplatasaurus araukanicus in Powell (2003). D'Emic et al. (2009) did not assign the Loricosaurus osteoderms to any genus or species.

It's quite likely that at least some of the osteoderms belong to Neuquensaurus australis. The larger osteoderms basically look the same as saltasaur osteoderms (see Figure 5 in D'Emic et al. 2009), at least one L. scutatus osteoderm is reported to have been associated with N. australis (Salgado 2003), and N. australis is known to have been armored from a different specimen (Salgado et al. 2005). Hold off on that synonymization party, though.* As mentioned previously, the Cinco Saltos sauropod material also includes Laplatasaurus araukanicus. Von Huene did not designate a singular specimen from the L. scutatus osteoderms as a holotype, and since we know that osteoderms are widespread among titanosaurs, there's no reason to assume that all of the type series belongs to one taxon. Therefore, the type series could very well include osteoderms from two (or more; we're dealing with titanosaurs in Argentina, after all) titanosaur species.

*By the way, if you were to consider the osteoderms diagnostic, Loricosaurus is an older name than Neuquensaurus, which could then also swallow Saltasaurus in the bargain if you're also of the party that lumps Neuquensaurus and Saltasaurus. They're all younger than Microcoelus, though. Unfortunately for Loricosaurus, titanosaur osteoderms are not known to be diagnostic for taxonomic purposes.

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