51 MUSEO DE HISTORIA NATURAL Y CULTURAL DEL DESIERTO DE ATACAMA CALAMA, CHILE FIGURE 4. Ophthalmosauridae indet. MUHNCAL.20189. A, Partial cast of the most anterior block preserving teeth. B, anatomical interpretation of the previous. C, detail of one of the teeth preserved in A. D, cervical centrum and its respective neural arch. E, presacral centrum. F, middle caudal centrum. Anatomical Abbreviations: acas, striated acellular cemental ring; an, neural arch; c, rib; cc?, cervical rib?; ccm, middle caudal centrum; cec, cervical centrum; co, crown; cn, neural canal; cps, presacral centrum; dp, diapophysis; dr, replacement tooth; fan, facets of neural arch; fcc, facet of cervical rib; m, maxilla; no, notochordal canal; p, premaxilla; pp, parapophysis; qv, ventral keel; ra, root; si, synapophysis; vy, gypsum veins. Scale bar = 5 cm, except C = 1 cm. Ribs―Proximal fragments of at least eight ribs are exposed in the recovered blocks. These feature different cross sections ranging from nearly square to oval, probably reflecting different points along different ribs. Square sections indicate fragments proximal to the double-headed joints in the ribs, while oval sections correlate with a more distal position within the rib. Several fragments of fine ribs occur associated with the presacral fragmentary centra and preserved median caudals.
52 MUSEO DE HISTORIA NATURAL Y CULTURAL DEL DESIERTO DE ATACAMA CALAMA, CHILE OPHTHALMOSAURIDAE INDET. (Figs. 5-7) Material―MUHNCAL.20187, the right posterior part of a skull. Locality, horizon and age―Informal locality of Biese 3, southwest of the city of Calama, Atacama desert, northern Chile. Cerro Campamento Formation, early Oxfordian. FIGURE 5. Ophthalmosauridae indet. MUHNCAL.20187. A, skull in right lateral view. B, anatomical interpretation of the previous. C, right lateral view of the skull, removing block 2 that preserves the elements posterior to the orbit. D, anatomical interpretation of the previous. Anatomical Abbreviations: as, sclerotic ring; esd, right stapes; fr, frontal; gs, salt gland; l, lacrimal; n, nasal; ne, external naris; opd, right opisthotic; pa, parietal; pf, postfrontal; po, postorbital; prf, prefrontal; ptd, right pterygoid; s, supratemporal; sut, suture; y, jugal. Scale bar = 5 cm. Description of MUHNCAL.20187 Preservation―The skull is three-dimensionally preserved. The posteromedial part of the skull (block 1) and the posterior portion of the orbit (block 2) are currently separated, but in the original concretion both fragments were in contact through the matrix before preparation. A third fragment (block 3) was recovered after preparation from a loose block of the same original concretion. This corresponds to the medioposterior part of the skull, conserving the posterior part of the right pterygoid and most of the right stapes. Block 1 is internally filled with limestone, preserving various internal bone casts or part of the internal periosteal tissue. All three blocks show slight dorsoventral flattening. The right opisthotic in block 1 is displaced dorsally from its anatomical position and obliquely exposes part of the otic capsule. Ontogeny―the right stapes is well fused with the posterior portion of the opisthotic, preserving a suture line; however, both elements make up a synostotic unit. Dorsally, internal sutural scars between the right parietal, right frontal, and right nasal are visible. Especially between the frontal and the nasal, the suture is interdigitated. In addition, the presence of an almost completely filled sclerotic
53 MUSEO DE HISTORIA NATURAL Y CULTURAL DEL DESIERTO DE ATACAMA CALAMA, CHILE ring is a characteristic that is considered indicative of a juvenile stage (Fernández et al., 2005; Bennett, 2015). On the other hand, the well-defined shape of the otic capsule, plus the elongated stapes axis and well-developed distal facet, are features seen in large juvenile and adult ichthyosaurs, as exemplified in the genus Stenopterygius (Miedema and Maxwell, 2019: figs.3 and 5). Based on these considerations, the specimen is interpreted here as a subadult individual. Skull―In right lateral view of block 1 (Fig. 5A, B) it can be seen that the contour of the internal naris is delimited by the dorsal surface of the nasal and by a descending septum of the same element. The middle part of this septum has a suture and its most ventral portion is interpreted here as a fragment of the lacrimal. The nasal extends posteromedially, with a posterior process visible in right lateral view. The highest (dorsal) part of block 1 is represented by the right parietal. The posterior half of the right eyeball is preserved, with the posterior half of the articulated sclerotic ring. Four sclerotic bones are articulated, suggesting that the entire ring was probably composed of eight to nine bones. The orbital portion of each scleral plate is flattened. The posterior orbital counterpart is preserved in block 2 as an internal cast below the postorbital. Block 3 is a small fragment that includes the right stapes, the posterior fragment of the right opisthotic, part of the basioccipital, and the posterior part of the right pterygoid (Fig. 5C, D). In dorsal view (Fig. 6A, B) the frontal can be seen as a small element, slightly prominent in the midline and bordered anteriorly by the prefrontal and nasal. The frontal is subtriangular and has a rounded anterior suture with the nasal. Posteriorly, the frontal is excluded from the anterior margin of the supratemporal fenestra by the contact between the parietal and the prefrontal. The prefrontal contacts the nasal through a non-interdigitated suture. A notable feature of the prefrontal is the presence of a distinctive structure that correlates with a salt gland (see Discussion). The postfrontal extends over the margin of the superior orbit. In the lateroventral part of block 2 a suture can be seen, here interpreted as the contact between the postorbital and the jugal. The posterior part of the jugal is slender and not expanded. The postorbital shows a prominent dorsal orbital rim. The posterodorsal part of block 2 preserves part of the supratemporal, but its fragmentary condition makes it impossible to evaluate its contour. In the right lateral view of block 3, the most posterior elements available include most of the right stapes, the posterior part of the right opisthotic, and the posterior part of the right pterygoid. In dorsal view (Fig. 6A, B) it can be seen that most of the available cranial roof corresponds to the right nasal, which extends posteromedially and encloses the external nostril. The nasal also extends posteromedially, suggesting that the two frontals do not meet in the midline. However, the preserved elements correspond to internal septa and do not necessarily reflect the external (dorsal) topology of the cranial elements. The right frontal contacts anteriorly with the right nasal through a simple rounded suture. Judging from the preserved
54 MUSEO DE HISTORIA NATURAL Y CULTURAL DEL DESIERTO DE ATACAMA CALAMA, CHILE cast, the anteromedial extension of the frontal has a rounded edge and a rough inner surface. On the other hand, the right parietal is a thick vertical tabular element that briefly overhangs the anterior margin of the temporal fossa. The contact between the frontal and the parietal has a posterior medial extension that can be correlated with the temporal process on the external surface of the frontal; however, the preserved portion reflects the internal relationship of these elements, while their external sutural topology could differ. The posterior contact of the parietal is delimited by an incomplete laterally expanded element, being consistent with the supraoccipital. However, this bone does not present any informative anatomical features. In dorsal view, two bones of the sclerotic ring can be seen, being convex and recurved in the midline, thus enveloping the eyeball. The anterior part of the temporal fossa is bounded by the parietal, prefrontal, and postfrontal. In dorsal view, block 2 shows a small cast fragment of the squamosal and postfrontal+postorbital. After preparation, part of the limestone matrix was kept to mark the relative position between blocks 1 and 2. In ventral view (Fig. 6C, D), most of the right pterygoid can be assessed by fragments preserved in blocks 1 and 3. In block 1, the lateral (outer) margin of the pterygoid is preserved as mineralized bone tissue, while that part of the medial surface has been lost, but retains its contour. The medial portion of the pterygoid is preserved as a cast, representing a negative of the actual dorsal surface of the bone. A rounded convex structure reflects the mold of the concave pterygoid fossa (Fig. 6D), as described by Yin et al. (2021: fig.4I). The posterior part of the pterygoid preserved in block 1 has a medial suture contact with an incomplete element, interpreted as a basiesphenoid fragment. The posterior portion of the right pterygoid present in block 3 is missing a small section of its most posterior margin; however, it allows distinguishing the presence of two posterior projections (Fig. 6D) which correlate with the forked process described by Fischer et al. (2012). Considering the information present in all the pterygoid fragments, it is possible to recognize that the ventral face of said element corresponds to an elongated, triangular, flattened bone, with a medial constriction at the level of the posterior margin of the orbit and with a posterior extension with two projections. The right pterygoid moved medially from its anatomical position during burial. Ventrally, block 1 shows three sclerotic bones, as well as the basal section of the epipterygoid (this is best seen in the occipital view) and the basal section of the dorsal lamina of the pterygoid (Fig. 6D). In the middle part of block 1, two axially aligned bone fragments are preserved. These are interpreted as fragments of a mandibular ramus. Its fragmentary state does not provide relevant anatomical characteristics.
55 MUSEO DE HISTORIA NATURAL Y CULTURAL DEL DESIERTO DE ATACAMA CALAMA, CHILE FIGURE 6. Ophthalmosauridae indet. MUHNCAL.20187. A, dorsal view of the skull. B, anatomical interpretation of the previous. C, ventral view of the skull. D, anatomical interpretation of the previous. Anatomical Abbreviations: as, sclerotic ring; bs, fragment of the basesphenoid; ept, epipterygoid; esd, right stapes; fr, front; fmc, concave medial pterygoid fossa; fra, mandibular ramus fragments; i?, indeterminate bone; ldpt, dorsal lamella of pterygoid; n, nasal; ne, external naris; opd, right opisthotic; pa, parietal; pf, postfrontal; po, postorbital; pr, prefrontal; ptd, right pterygoid; s, supratemporal; so, supraoccipital; sptb, pterygoid/basisphenoid suture. Scale bar = 5 cm.
56 MUSEO DE HISTORIA NATURAL Y CULTURAL DEL DESIERTO DE ATACAMA CALAMA, CHILE In dorsal view of block 3, a suture is observed between the medial head of the stapes and an anterior element that correlates anatomically with the posterior part of the right prootic, although no relevant anatomical features are observed here (Fig. 7A). Taphonomically, it appears that the right stapes is deformed by dorsoventral compression. The stapedial axis is very slender and tabular, with a dorsal square outline and a prominent square facet anteriorly. The sutures between the stapes and the opisthotic are visible in the posterior and lateral views. The last two elements are crushed dorsoventrally on the posterior fragment of the right pterygoid (Fig. 7B, C). The occipital view of block 1 (Fig. 7D, E) shows several basicranial elements. Medially, the supraoccipital is in contact with the right opisthotic, since the latter is displaced dorsally from its anatomical position. The right opisthotic is exposed in cross section, with its posterior attached to the right stapes in block 3. The right opisthotic has a suboval outline with a deep lateroventral indentation that correlates with the groove for transmission of the hyomandibular branch of the facial nerve. (VII) or the glossopharyngeal nerve (XI) (see Zverkov and Prilepskaya, 2019: Fig. 10G, H). In addition, the opisthotic preserves the posterior three-dimensional cast of the otic capsule. The latter shows the impression of the posterior vertical semicircular canal and the horizontal semicircular canals forming a “V-shaped” structure. Both canals taper towards the dorsal border of the bone. The posterior view of block 1 also shows the dorsal lamina of the right pterygoid and a vertical bone between the pterygoid and the orbit, here interpreted as the epipterygoid. The posterior view of the sclerotic ring shows that this element is well preserved, with no relevant signs of deformation.
57 MUSEO DE HISTORIA NATURAL Y CULTURAL DEL DESIERTO DE ATACAMA CALAMA, CHILE FIGURE 7. Ophthalmosauridae indet. MUHNCAL.20187. A, dorsal view of block 3; B, occipital view of block 3; C, anatomical interpretation of the previous; D, occipital view of block 1; E, anatomical interpretation of the previous. Anatomical Abbreviations: am, ampulla; as, sclerotic ring; bs, basisphenoid (articulation with the pterygoid); cme, medial head of right stapes (fragment); ept, ectopterygoids; esd, right stapes; fc, right square facet; fppt, triradiate process (forked process) of the right pterygoid; icsh, impression of the horizontal semicircular canal of the right opisthotic; icsp, impression of the posterior vertical semicircular canal of the right opisthotic; ldpt, dorsal lamella of pterygoid; llpt, lateral lamella of pterygoid; pa, parietal; ptd, right pterygoid; opd, right opisthotic; so, supraoccipital; yn; groove for the transmission of the hyomandibular branch of the facial (VII) or glossopharyngeal (XI) nerve; su, suture (stapes/opisthotic). Scale bar = 5 cm.
58 MUSEO DE HISTORIA NATURAL Y CULTURAL DEL DESIERTO DE ATACAMA CALAMA, CHILE DISCUSSION Taxonomic determination of MUHNCAL.20189 ―The presence of a striated acellular cementum ring in the teeth of MUHNCAL.20189 is a condition similar to that previously described in other ophthalmosaurids (Fischer, 2016: fig. 1). In addition, the robust, triangular and striated crown with an oval basal section and narrower than its respective root, are characteristics commonly observed among ophthalmosaurids worldwide (Arkhangelsky, 1998: fig. 2; Kear, 2005: fig. 16; Fischer et al. al., 2011: Fig. 4; Fischer, 2016: Fig. 1; Moon and Kirton, 2016: Fig. 18; Tyborowski, 2016: Fig. 4; Prasad et al., 2017: Figs 6, 7; Delsett et al. ., 2018: Fig. 6; Zverkov and Efimov, 2019: Fig. 8; Zverkov and Prilepskaya, 2019: Fig. 11; Jacobs and Martill, 2020: Fig. 12). Therefore, MUHNCAL.20189 is here referred to the clade Ophthalmosauridae. Its incomplete nature precludes a more meaningful determination for the time being. However, its juvenile ontogenetic stage and comparatively large size suggest that it belongs to a different taxon than MUHNCAL.20187. Salt gland in MUHNCAL.20187―Remains of ichthyosaur salt glands have been previously recognized in Ophthalmosaurus natans (Marsh, 1878), from the Bajocian-Oxfordian of the Sundance Formation in the United States (Wahl, 2012). In addition, the presence of a subdivided nasal opening has been related to functions of respiration and salt excretion (Massare et al., 2021). The existence of a circular posterior region of the external naris, formed by different bones in several Lower Jurassic genera (i.e., Temnodontosaurus, Leptonectes, Excalibosaurus, Hauffiopteryx) was considered the ancestral condition that led to the specialized separate naris. However, the circular posterior region of the external naris (possible basal condition), already reflected the existence of a specialized structure, probably related to the presence of salt glands (Massare et al., 2021). MUHNCAL.20187 appears to be the first documented case of a threedimensionally preserved salt gland in ichthyosaurs. The tissue here interpreted as a salt gland is consistently located in a dorsal position, anterior to the orbit, but posterior to a descending nasal septum. The preserved edge of the external naris is anterior to this septum. The bones posterior to the septum are missing, although these leave enough space for the anterior half of the orbit and for a probable second nasal opening. In that case, this opening would be located directly below the salt gland. Structurally, the tissue studied here (Fig. 8A, B) presents a botryoidal surface remarkably similar to that described by Fernández and Gasparini (2000) for an endocranial cast referred to the metriorhynchid Cricosaurus araucanensis (Gasparini and Dellapé, 1976), from the Tithonian of the Argentinian Patagonia. Such morphology reinforces its adscription to a salt gland, further suggesting that the nature, function and topology of this gland could be similar in both Ophthalmosauridae and Metriorhynchidae. Records of ichthyosaurs from Chile―The oldest ichthyosaur remains found in Chile were reported by Suárez and Bell (1992), who described a single tooth associated with other unidentified bone elements, all recovered from the Upper Triassic Quebrada del Salitre Formation, Región de Atacama, northern Chile. Suárez and Otero (2010) described two indeterminate ichthyosaur specimens
59 MUSEO DE HISTORIA NATURAL Y CULTURAL DEL DESIERTO DE ATACAMA CALAMA, CHILE found in two different Lower Jurassic localities of northern Chile. The first generic determination of an ichthyosaur from the Jurassic of Chile was provided by Otero and Sepúlveda (2020) who referred to Temnodontosaurus sp. a large fragmentary rostrum from the Hettangian-Sinemurian of the Región de Antofagasta. Burmeister and Giebel (1861) described an isolated vertebra from levels of Bajocian age exposed southeast of Copiapó, assigning the material to a new species, ‘Ichthyosaurus leucopetraeus’ (nomen dubium, currently considered as Ichthyosauria indet.; see Pardo-Pérez et al., 2015). Tavera (1981) described new associated remains from Bajocian levels southeast of Copiapó, referring them to the species Ichthyosaurus acutirostris Owen, 1840 and to ‘Ichthyosaurus posthumus’ (Wagner, 1852; nomen dubium). Later Gasparini et al. (2000) recognized a skull belonging to a Metriorhynchoidea, while Otero et al. (2020a) identified vertebrae from an indeterminate plesiosaur, all among the bony elements originally described by Tavera (1981). The rest of the ichthyosaur material positively identified by Tavera (1981) is not sufficient to ensure a generic or specific identification and should be kept as Ichthyosauria indet. (Pardo-Perez et al., 2015). Philippi (1895) proposed a new species, ‘Ichthyosaurus immanis’, based on material of Tithonian-age from Cajón el Durazno, then considered Chilean territory (currently located in central-western Argentina). Within the hypodigm of ‘Ichthyosaurus immanis’, the redescription of the material made it possible to verify that the ichthyosaur remains belonged to two different individuals, additionally including an isolated plesiosaur vertebra, which is why the species was considered a nomen dubium (Otero et al. ., 2015). Indeterminate ichthyosaur finds have also been reported in Oxfordian levels of central Chile (Pardo-Pérez et al., 2015). Biese (1961) reported the presence of ichthyosaur remains at various Middle to Upper Jurassic levels at Cerritos Bayos, northern Chile. Subsequently, Chong and Gasparini (1976) added several finds of indeterminate ichthyosaurs, with a total of eight localities in northern Chile, whose ages range from Early Jurassic to Late Jurassic. Despite these frequent occurrences, no taxonomic determinations or descriptions of the material were provided. However, both the work of Biese (1961) and that of Chong and Gasparini (1976) are fundamental references for future research on marine vertebrates of the Jurassic in the Atacama desert. The most relevant paleontological site with ichthyosaurs in Chile is the Tyndall Glacier, in the extreme south of the country. In this place, an accumulation of ichthyosaurs of Valanginian-Hauterivian age has provided several dozen specimens, being able to identify the species Platypterygius hauthali (von Huene, 1927) as well as still undetermined ophthalmosaurids (Shultz et al., 2003; PardoPérez et al. ., 2012; 2015; Stinnesbeck et al., 2014). Paleoecology―Available rostral elements from MUHNCAL.20035 show that this ichthyosaur had a very thin and sharp rostrum and jaw. Among Upper Jurassic ichthyosaurs, these proportions are unusual. In contrast, such ratios are common among Lower Jurassic Leptonectidae, such as Eurhinosaurus, Excalibosaurus, Leptonectes, or Wahlisaurus (Maisch and Matzke, 2000; McGowan, 1986; Lomax, 2017). The late Oxfordian age of MUHNCAL.20035 represents an important
60 MUSEO DE HISTORIA NATURAL Y CULTURAL DEL DESIERTO DE ATACAMA CALAMA, CHILE chronostratigraphic gap with the known Leptonectidae. Apart from the unusually thin rostrum and jaw, there are no diagnostic features that would allow a meaningful determination. However, even in its broad taxonomic determination (Neoichthyosauria indet.), MUHNCAL.20035 represents an ichthyosaur with a remarkably graceful rostrum, comparable to extant sailfishes and swordfishes (Nakamura, 1985). The rostrum and specialized mandibles suggest a specific and convergent trophic adaptation with the Cenozoic-Recent Istiophoridae Gracilirostra (De Gracia et al., 2022). The juvenile ontogenetic stage of MUHNCAL.20189 and its relatively large size contrast with the near-adult stage and considerably smaller comparative size of MUHNCAL.20187. This suggests that each specimen belongs to a different taxon within the Ophthalmosauridae. MUHNCAL.20189 is characterized by comparatively small teeth with robust crowns, without evidence of significant wear. These characteristics have been considered typical of generalist ophthalmosaurids (sensu Fischer et al., 2016: fig. 1). MUHNCAL.20187 does not preserve the teeth, which makes it difficult to establish trophic relationships based on the available material. Despite this, the size and proportions of the preserved elements of MUHNCAL.20187 suggest a total skull length close to 50 cm (Fig. 8C-E), which is consistent with an estimated body length of between 3 and 4 meters. In summary, the three ichthyosaur specimens from northern Chile represent three different ecomorphotypes, including a relatively large and generalist form, a still indeterminate, highly derived form with a very slender face and jaw, and a possible smaller form within Ophthalmosauridae. FIGURE 8. A, antero-dorsal view of MUHNCAL.20187 skull, indicating the location of the salt gland in the anterior margin of the temporal fenestra. B, detail of the salt gland. C, outline of the skull elements preserved in MUHNCAL.20187, in right lateral view. D, outline of the same elements in dorsal view. E, Estimated body size based on the MUHNCAL.20187 skull.
61 MUSEO DE HISTORIA NATURAL Y CULTURAL DEL DESIERTO DE ATACAMA CALAMA, CHILE Paleobiogeography―The presence of Ophthalmosauridae in the Oxfordian of the Atacama Desert was expected, considering their previously known records from southern Gondwana. These include an indeterminate Ophthalmosauridae from the Aalenian-Bajocian of Argentina (Fernández, 2003), Mollesaurus perialus, from the Bajocian of Neuquén, Argentina (Fernández, 1999), and the Tithonian records of Caypullisaurus bonapartei Fernández (1997), Arthropterygius thalassonotus Campos et al. (2020), Catutosaurus gaspariniae Fernández et al. (2021) and Sumpalla argentina (Campos et al., 2021b), also in Neuquén. Indeterminate Ophthalmosauridae are known from the Valanginian-Hauterivian Agrio Formation in the same area (Lazo et al., 2018). Complementing the Gondwanan record, materials referable to Ophthalmosauridae have also been recorded from the Upper Kimmeridgian of India (Prasad et al., 2017). Specimens attributable to indeterminate ophthalmosaurids have been described from the Upper Jurassic of Madagascar and the Tithonian of the Ameghino Formation in the Antarctic Peninsula (Campos et al., 2021a). In turn, several dozen individuals referable to Ophthalmosauridae have been recorded in the ValanginianHauterivian of southernmost Chile, including some specimens referable to Platypterygius hauthali (Pardo-Pérez et al., 2012; 2015). Records of Ophthalmosauridae in northern Gondwana and the Caribbean include indeterminate forms recovered from Late Oxfordian units in Cuba (Fernández and Iturralde-Vinent, 2000), as well as ‘Platypterygius’ sachicarum (PáramoFonseca, 1997; Maxwell et al. , 2019; assigned to Kyhytysuka sachicarum by Cortés et al., 2021) and Muiscasaurus catheti (Maxwell et al., 2016; PáramoFonseca et al., 2021), both from the Hauterivian-Aptian of Colombia. The close relationships between the marine fauna of the Tethys and that of the seas of southeastern Gondwana during the Callovian-Oxfordian are largely linked to the fully functional Caribbean Marine Seaway (sensu Iturralde-Vinent, 2003). This has been supported by records of marine invertebrates (Damborenea and Manceñido, 1979), especially ammonoids (Riccardi, 1991), as well as vertebrates including Osteichthyes (Arratia, 2008; 2015), Metriorhynchidae crocodiles (Gasparini, 1996; Gasparini et al. ., 2000), Cryptoclididae plesiosaurs (Otero et al., 2020b), Ophthalmosauridae ichthyosaurs (Fernández and Iturralde-Vinent, 2000; Fernández, 2003; Prasad et al., 2017), Chondrichthyes (Otero et al., 2021) and even Rhamphorhynchinae pterosaurs (Alarcón-Muñoz et al., 2021). However, growing evidence also points to faunal exchange through the Trans-Erythrean Seaway as early as the Tithonian. This hypothesis is supported by recent records of ichthyosaurs in the Late Jurassic in India (Prasad et al., 2017), as well as in Madagascar and Antarctica (Campos et al., 2021a), while other marine diapsids such as plesiosaurs also support this biogeographical connection during the Tithonian (O’Gorman et al., 2018). Thus, a more complex biogeographic picture of marine faunal exchange during the Upper Jurassic is complemented.
62 MUSEO DE HISTORIA NATURAL Y CULTURAL DEL DESIERTO DE ATACAMA CALAMA, CHILE The present contribution describes new ichthyosaur material recovered in the Atacama desert, northern Chile. A very thin, fragmentary rostrum and jaw are here determined as Neoichthyosauria indet.; its rostral proportions are unusual among ichthyosaurs known during the Oxfordian, suggesting the presence of a highly specialized form, similar in general morphology to the Lower Jurassic Leptonectidae ichthyosaurs, and convergent to the extant Istiophoridae Gracilirostra swordfishes. This specimen represents a new ecomorphotype in the Upper Jurassic of northern Chile. On the other hand, two additional specimens constitute the first local evidence of the clade Ophthalmosauridae. One of them corresponds to a fragmentary face of a relatively large young individual, with distinctive dentition typical of the group. This specimen was recovered from upper Oxfordian levels of the Cerro Campamento Formation. A second specimen corresponds to a fragmentary skull of an almost adult individual, from Lower Oxfordian levels of the Cerro Campamento Formation. The specimens reported here represent three different ecomorphotypes and probably three different taxa, suggesting considerable ichthyosaur diversity in southeastern Gondwana during the Oxfordian. MUHNCAL.20187 highlights the preservation of an anatomical structure, whose shape and location are consistent with the presence of a salt gland. Apparently, this finding would correspond to the first record in Ichthyosauria of a salt gland preserved in three dimensions, thus confirming previous inferences regarding this organ, established on the basis of osteological characteristics. CONCLUSIONS
63 MUSEO DE HISTORIA NATURAL Y CULTURAL DEL DESIERTO DE ATACAMA CALAMA, CHILE RAO, SSA and JAM had the support of the Corporación de Cultura y Turismo de Calama (Culture and Tourism Corporation of Calama, Chile) and the Proyecto Anillo (Ring Project) ACT-172099 ANID-Chile. JAM and SSA were also supported by the ANID Scholarship Program for PhD studies in Chile. JPP was supported by ANID Project PAI77200036 “Revealing the diversity and paleobiology of Cretaceous ichthyosaurs from a fossil deposit in the Magallanes Region, southern Chile”. The preparation of MUHNCAL.20187 was carried out in the facilities of the Laboratorio de Ontogenia y Filogenia, Departamento de Biología, Facultad de Ciencias, Universidad de Chile (Santiago, Chile). Thanks to I. Ramírez (Corporación de Cultura y Turismo de Calama) for his valuable help with photographs during the lockdown time in 2020. ACKNOWLEDGMENTS
64 MUSEO DE HISTORIA NATURAL Y CULTURAL DEL DESIERTO DE ATACAMA CALAMA, CHILE REFERENCES Alarcón-Muñoz, J.; Otero, R. A.; Soto-Acuña, S.; Vargas, A. O.; Rojas, J.; Rojas, O. 2021. First record of a Late Jurassic Rhamphorhynchine pterosaur from Gondwana. Acta Palaeontologica Polonica 66: 571–583. Arkhangensky, M. S. 1998. On the ichthyosaurian genus. Paleontological Journal 32: 611–615. Arratia, G. 2008. The varasichthyid and other crossognathiform fishes, and the break-up of Pangaea. Geological Society (London), Special Publications 295:71–92. Arratia, G. 2015. Los peces osteíctios fósiles de Chile y su importancia en los contextos paleobiogeográfico y evolutivo. En: Rubilar-Rogers, D., R.A. Otero, A. Vargas, and M. Sallaberry (eds.), Vertebrados Fósiles de Chile, pp. 35–83. Publicación Ocasional del Museo Nacional de Historia Natural 63. Santiago, Chile. Baur, G. 1887. On the morphology and origin of the Ichthyopterygia. American Naturalist 21: 837–840. Bennett, S. P. 2015. An investigation into ichthyosaur ontogeny, sexual dimorphism and body size evolution. Thesis submitted for the degree of Doctor of Philosophy, Royal Holloway College, 303 p. Benson, R. B. J.; Evans, M.; Smith, A. S.; Sassoon, J.; Moore-Faye, S.; Ketchum, H. F.; Forrest, R. 2013. A Giant Pliosaurid Skull from the Late Jurassic of England. PLOS ONE 8: e65989. 34 p. Biese, W. 1957. Der Jura von Cerritos Bayos, Calama, República de Chile, Provinz Atacama. Geologische Jahrbuch 72:439–493. Biese, W. 1961. El Jurásico de Cerritos Bayos. Instituto de Geología (Chile), publicación n° 19, Universidad de Chile, Santiago, Chile, 61 pp. Burmeister, H.; Giebel, C. 1861. Die Versteinerungen von Juntas im Thal des Rio Copiapo. Abhandlungen der Naturforschenden Gesellschaft zu Halle 6:122– 132. Campos, L.; Fernández, M.; Herrera, Y. 2020. A new ichthyosaur from the Late Jurassic of northwest Patagonia (Argentina) and its significance for the evolution of the narial complex of the ophthalmosaurids. Zoological Journal of the Linnean Society 188:180–201. Campos, L.; Fernández, M. S.; Herrera, Y.; Garrido, A. 2021a. Morphological disparity in the evolution of the ophthalmosaurid forefin: new clues from the Upper Jurassic of Argentina. Papers in Palaeontology, doi:10.1002/spp2.1374. 26 p.
65 MUSEO DE HISTORIA NATURAL Y CULTURAL DEL DESIERTO DE ATACAMA CALAMA, CHILE Campos, L.; Fernández, M. S.; Herrera, Y.; Talevi, M.; Concheyro, A.; Gouiric-Cavalli, S.; O’Gorman, J. P.; Santillana, S. N.; Acosta-Burlaille, L.; Moly, J. J.; Reguero, M. A. 2021b. Bridging the southern gap: First definitive evidence of Late Jurassic ichthyosaurs from Antarctica and their dispersion routes. Journal of South American Earth Sciences 109:103259. 12 p. Carter J. 1846. Notice of the jaws of an Ichthyosaurus from the chalk in the neighborhood of Cambridge. Reports of the British Association for the Advancement of Science 1845: 60. Cortés, D.; Maxwell, E. E.; Larsson, H. C. 2021. Re-appearance of hypercarnivore ichthyosaurs in the Cretaceous with differentiated dentition: revision of ‘Platypterygius’ sachicarum (Reptilia: Ichthyosauria, Ophthalmosauridae) from Colombia. Journal of Systematic Palaeontology 19:969–1002. Chong, G.; Gasparini, Z. 1976. Los vertebrados mesozoicos de Chile y su aporte geopaleontológico. En: Actas del IV Congreso Geológico Argentino. Bahía Blanca: 45–67. Damborenea, S.; Manceñido, M. 1979. On the palaeogeographical distribution of the pectinid genus Weyla (Bivalvia, Lower Jurassic). Palaeogeography, Palaeoclimatology, Palaeoecology 27:85–102. de Blainville, H.M.D. 1835. Description de quelques espèces de reptiles de la Californie précédé de l’analyse d’un système général d’erpétologie et d’amphibiologie. Nouvelles Annales du Muséum d’Histoire Naturelle de Paris (Série 3) 4:233–296. De Gracia, C.; Correa-Metrio, A.; Carvalho, M.; Velez-Juarbe, J.; Přikryl, T.; Jaramillo, C.; Kriwet, J. 2022. Towards a unifying systematic scheme of fossil and living billfishes (Teleostei, Istiophoridae). Journal of Systematic Palaeontology 20:1, 2091959. 13 p. Delsett, L. L.; Druckenmiller, P. S.; Roberts, A. J.; Hurum, J. H. 2018. A new specimen of Palvennia hoybergeti: implications for cranial and pectoral girdle anatomy in ophthalmosaurid ichthyosaurs. PeerJ 6: e5776. 57 p. Duhart, P.; Muñoz, J.; Quiroz, D.; Mestre, A.; Varas, G. 2018. Carta Sierra Gorda, Región de Antofagasta. Servicio Nacional de Geología y Minería, Carta Geológica de Chile, Serie Geología Básica 198, 1 mapa escala 1:100.000. 1 CD con anexos. Santiago, Chile. Fernández, M. S. 1997. A New Ichthyosaur from the Tithonian (Late Jurassic) of the Neuquén Basin, Northwestern Patagonia, Argentina. Journal of Paleontology 71:479–484. Fernández, M. S. 1998. Nuevo material de Caypullisaurus bonapartei Fernández (Reptilia: Ichthyosauridae) del Jurásico Superior de la Cuenca Neuquina, Argentina. Ameghiniana 35: 21–24.
66 MUSEO DE HISTORIA NATURAL Y CULTURAL DEL DESIERTO DE ATACAMA CALAMA, CHILE Fernández, M. S. 1999. A New Ichthyosaur from the Los Molles Formation (Early Bajocian), Neuquen Basin, Argentina. Journal of Paleontology 73:677–681. Fernández, M. S. 2003. Ophthalmosauria (Ichthyosauria) forefin from the Aalenian-Bajocian boundary of Mendoza Province, Argentina. Journal of Vertebrate Paleontology 23:691–694. Fernández, M. S.; Gasparini, Z. 2000. Salt glands in a Tithonian metriorhynchid crocodyliform and their physiological significance. Lethaia 33:269–276. Fernández, M. S.; Iturralde-Vinent, M. 2000. An Oxfordian Ichthyosauria (Reptilia) from Viñales, western Cuba: paleobiogeographic significance, Journal of Vertebrate Paleontology 20:191–193. Fernández, M. S.; Archuby, F.; Talevi, M.; Ebner, R. 2005. Ichthyosaurian Eyes: Paleobiological Information Content in the Sclerotic Ring of Caypullisaurus (Ichthyosauria, Ophthalmosauria). Journal of Vertebrate Paleontology 25:330– 337. Fernández, M. S.; Campos, L.; Maxwell, E. E.; Garrido, A. C. 2021. Catutosaurus gaspariniae, gen. et sp. nov. (Ichthyosauria, Thunnosauria) of the Upper Jurassic of Patagonia and the evolution of the ophthalmosaurids. Journal of Vertebrate Paleontology e1922427: 14 p. Fischer, V. 2016. Taxonomy of Platypterygius campylodon and the diversity of the last ichthyosaurs. PeerJ 4: e2604. 21 p. Fischer, V.; Clément, A.; Guiomar, M.; Godefroit, P. 2011. The first definite record of a Valanginian ichthyosaur and its implications on the evolution of postLiassic Ichthyosauria. Cretaceous Research 32:155–163. Fischer, V.; Maisch, M. W.; Naish, D.; Kosma, R.; Liston, J.; Joger, U.; Krüger, F. J.; Pardo-Pérez, J.; Tainsh, J.; Appleby, R. M. 2012. New Ophthalmosaurid Ichthyosaurs from the European Lower Cretaceous Demonstrate Extensive Ichthyosaur Survival across the Jurassic–Cretaceous Boundary. PLOS ONE 7: e29234. 23 p . Fischer, V.; Bardet, N.; Benson, R. B. J.; Arkhangelsky, M. S.; Friedman, M. 2016. Extinction of fish-shaped marine reptiles associated with reduced evolutionary rates and global environmental volatility. Nature Communications 7:10825. 12 p. Gasparini, Z. 1996. Biogeographic evolution of South American crocodilians. En: Arratia, G.; Cione, L. A. (eds.), Contributions of southern South America to vertebrate paleontology, pp. 159–184. Münchner Geowissenschaftliche Abhandlungen Reihe A Geologie und Paläontologie. Verlag Dr. Friedrich Pfeil, Munich, Germany. Gasparini Z.; Dellapé, D. 1976. Un nuevo cocodrilo marino (Thalattosuchia, Metriorhynchidae) de la Formación Vaca Muerta (Jurasico, Tithoniano) de la
67 MUSEO DE HISTORIA NATURAL Y CULTURAL DEL DESIERTO DE ATACAMA CALAMA, CHILE Provincia de Neuquén (República Argentina). Congreso Geológico Chileno 1: c1–c21. Gasparini, Z.; Vignaud, P.; Chong, G. 2000. The Jurassic Thalattosuchia (Crocodyliformes) of Chile: a paleobiogeographic approach. Bulletin Société Géologique de France 171:657–664. Houssaye, A.; Nakajima, Y.; Sander, P. 2018. Structural, functional, and physiological signals in ichthyosaur vertebral centrum microanatomy and histology. Geodiversitas 40:161–170. Huene, F. von. 1927. Beitrag zur Kenntnis mariner mesozoischer Wirbeltiere in Argentinien. Zentralblatt für Mineralogie, Geologie und Paläontologie, B 1927:22–29. Iturralde-Vinent, M. 2003. A brief account of the evolution of the Caribbean seaway: Jurassic to present. En: Prothero, D.; Ivany, L. C.; Nesbitt, E. A. (Eds.) From Greenhouse to Icehouse: The Marine Eocene-Oligocene Transition, pp. 386−396. Colombus University Press, New York. Jacobs, M. L.; Martill, D. 2020. A new ophthalmosaurid ichthyosaur from the Upper Jurassic (Early Tithonian) Kimmeridge Clay of Dorset, UK, with implications for Late Jurassic ichthyosaur diversity. PLOS ONE 15: e0241700. 38 p. Kear, B. P. 2005. Cranial morphology of Platypterygius longmani Wade, 1990 (Reptilia: Ichthyosauria) from the Lower Cretaceous of Australia. Zoological Journal of the Linnean Society 145:583–622. Lazo, D. G.; Talevi, M.; Cataldo, C. S.; Aguirre Urreta, B.; Fernández, M. S. 2018. Description of ichthyosaur remains from the Lower Cretaceous Agrio Formation (Neuquén Basin, west-central Argentina) and their paleobiological implications. Cretaceous Research 89:8–21. Lira, G. 1989. Geología del área pre-Andina de Calama, con énfasis en la estratigrafía y paleogeografía del Mesozoico, 22° a 22° 40′ latitud Sur, Región de Antofagasta. Tésis, Departamento de Geología, Universidad de Chile, Santiago. 211 pp. Inédito. Lomax, D. R. 2017. A new leptonectid ichthyosaur from the Lower Jurassic (Hettangian) of Nottinghamshire, England, UK, and the taxonomic usefulness of the ichthyosaurian coracoid, Journal of Systematic Palaeontology, 15: 387–401. Maisch, M. W.; Matzke, A. T. 2000. The Ichthyosauria. Stuttgarter Beiträge zur Naturkunde Serie B (Geologie und Paläontologie) 298:1–159. Marsh, O. C. 1878. A new Order of Extinct Reptiles (Sauronodonta), from the Jurassic Formation of the Rocky Mountains. American Journal of Science (Third Series) 17:85–86.
68 MUSEO DE HISTORIA NATURAL Y CULTURAL DEL DESIERTO DE ATACAMA CALAMA, CHILE Massare, J. A.; Wahl, W. R.; Lomax, D. R. 2021. Narial structures in Ichthyosaurus and other Early Jurassic ichthyosaurs as precursors to a completely subdivided naris. Paludicola 13:128–139. Maxwell, E. E. 2010. Generic reassignment of an ichthyosaur from the Queen Elizabeth Islands, Northwest Territories, Canada, Journal of Vertebrate Paleontology 30:403–415. Maxwell, E. E.; Dick, D. G.; Padilla, S.; Parra, M. L. 2016. A new Ophthalmosaurid Ichthyosaur from the Early Cretaceous of Colombia. Papers in Palaeontology 2:59–70. Maxwell, E. E.; Cortés, D.; Patarroyo, P.; Parra-Ruge, L. 2019. A new specimen of Platypterygius sachicarum (Reptilia, Ichthyosauria) from the Early Cretaceous of Colombia and its phylogenetic implications. Journal of Vertebrate Paleontology 39: e1577875. 12 p. McGowan, C. 1986. A putative ancestor for the swordfish-like ichthyosaur Eurhinosaurus. Nature 322:454−456. Miedema, F.; Maxwell, E. E. 2019. Ontogeny of the braincase in Stenopterygius (Reptilia, Ichthyosauria) from the Lower Jurassic of Germany. Journal of Vertebrate Paleontology e1675164:11 p Moon, B. C.; Kirton, A. E. 2016. Ichthyosaurs of the British Middle and Upper Jurassic, Part I, Ophthalmosaurus. Memoir of the Palaeontographical Society, London, 84 pp., pls. 1–30. Motani, R. 1997. Temporal and spatial distribution of tooth implantation in ichthyosaurs. pp. 81-103 in J. M. Callaway, E. L. Nicholls (eds.), Ancient Marine Reptiles. Academic Press, San Diego. 501 p. Motani, R. 1999. Phylogeny of the Ichthyopterygia. Journal of Vertebrate Paleontology, 19:473–496. Nakamura, I. 1985. An annotated and illustrated catalogue of marlins, sailfishes, spearfishes, and swordfishes known to date. Fao Fisheries Synopsis 5:1–65. O’Gorman, J.P.; Gouiric-Cavalli, S.; Scasso, A. E.; Reguero, M.; Moly, J. J.; AcostaBurlaille, L. 2018. A Late Jurassic plesiosaur in Antarctica: Evidence of the dispersion of marine fauna through the Trans-Erythraean Seaway? Comptes Rendus Palevol 17:158–165. Ossa-Fuentes, L.; Soto-Acuña, S.; Otero, R. A.; Alarcón, J.; Rojas, O. 2015. Nuevos ejemplares de peces óseos (Osteichthyes: Actinopterygii) del Jurásico Superior de Cerritos Bayos, Calama, norte de Chile. XIV Congreso Geológico de Chile, Actas Vol. III, Área Temática 5, Bioestratigrafía y Paleontología Andina, pp. 694–697. Octubre 4–8, 2015, La Serena, Chile.
69 MUSEO DE HISTORIA NATURAL Y CULTURAL DEL DESIERTO DE ATACAMA CALAMA, CHILE Otero, R. A.; Sepúlveda, P. 2020. First temnodontosaurid (Ichthyosauria, Parvipelvia) from the Lower Jurassic of the Atacama Desert, northern Chile. Journal of South American Earth Sciences 98:102459. 7 p. Otero, R.A.; Soto-Acuña, S; Salazar, S. 2015. Revisión taxonómica de Ichthyosaurus immanis Philippi 1895, del Jurásico Superior de la Cuenca Andina. XIV Congreso Geológico de Chile, La Serena. 4 p. Otero, R.A.; Pardo-Pérez, J.; Rojas, O.; Rojas, J. 2018. Ictiosaurios oftalmosáuridos (Ichthyopterygia, Ophthalmosauridae) del Oxfordiano del norte de Chile. Primer Congreso de Paleontología de Chile, Punta Arenas, Libro de Resúmenes, pp. 354‒357. Punta Arenas, Chile. Otero, R. A.; Soto-Acuña, J.; Rojas, J.; Rojas, O. 2020a. Primer registro de un plesiosaurio del Jurásico Medio de Ojo Opache, Calama, norte de Chile, con comentarios sobre registros similares en la Región de Atacama. Publicación Ocasional n° 2. Museo de Historia Natural y Cultural del Desierto de Atacama, Calama, Chile. 29 p. Otero, R. A.; Alarcón-Muñoz, J.; Soto-Acuña, S.; Rojas, J.; Rojas, O.; Ortíz, H. 2020b. Cryptoclidid plesiosaurs (Sauropterygia, Plesiosauria) from the Upper Jurassic of the Atacama Desert. Journal of Vertebrate Paleontology 40: e1764573. 15 p. Otero, R. A.; Figueroa Bravo, C.; Soto-Huenchumán, P.; Fernández Colleman, S.; Valenzuela Toro, A.; Gutstein, C. S. 2021. First record of Ischyodus (Chondrichthyes, Holocephali) from the Upper Jurassic of southwestern Gondwana. Acta Palaeontologica Polonica 66:623–630. Owen, R. 1840. Report on British fossil reptiles. Part I. – Report of the British Association for the Advancement of Science (Birmingham) 9:43–126. Páramo-Fonseca, M. E. 1997. Platypterygius sachicarum (Reptilia, Ichthyosauria), nueva especie del Cretácico de Colombia. Revista Ingeominas 6:6–12. Páramo-Fonseca, M. E.; García-Guerrero, J.; Benavides-Cabra, C. D.; PadillaBernal, S.; Castañeda-Gómez, A. J. 2021. A benchmark specimen of Muiscasaurus catheti from the upper Aptian of Villa de Leyva, Colombia: New anatomical features and phylogenetic implications. Cretaceous Research 119:104685. 22 p. Pardo-Pérez, J.; Frey, E.; Stinnesbeck, W.; Fernández, M. S.; Rivas, L.; Salazar, C.; Leppe, M. 2012. An ichthyosaurian forefin from the Lower Cretaceous Zapata Formation of southern Chile: implications for morphological variability within Platypterygius. Palaeobiodiversity and Palaeoenvironments 92:287–294. Pardo-Pérez, J.; Otero, R.A., Suárez, M.E. 2015. Síntesis del registro fósil de ictiosaurios (Reptilia: Ichthyosauria) en Chile. pp.: 113–150 in Rubilar-Rogers, D.; Otero, R. A.; Vargas, A. O.; Sallaberry M. (eds.), Vertebrados Fósiles de Chile. Publicación Ocasional del Museo Nacional de Historia Natural (Chile) 63. Santiago. 467 p.
70 MUSEO DE HISTORIA NATURAL Y CULTURAL DEL DESIERTO DE ATACAMA CALAMA, CHILE Parent, H. 2006. Oxfordian and Late Callovian ammonite faunas and biostratigraphy of the Neuquén-Mendoza and Tarapacá Basins (Jurassic, Ammonoidea, Western South-America). Boletín del Instituto de Fisiografía y Geología 76:1–70. Parent, H.; Schweigert, G.; Meléndez, G. 2006. Oxfordian perisphinctid ammonites from Chacay Melehue, Argentina. Paläontologische Zeitschrift 80:307–324. Philippi, R. A. 1895. Ichthyosaurus immanis Ph., nueva especie sudamericana de este jénero. Extracto de los Anales de la Universidad de Chile. Imprenta Cervantes, Calle de La Bandera 73, Santiago, Chile. 8 p. Prasad, G. V. R.; Pandey, D. K; Alberti, M.; Fürsich, F. T.; Thakkar, M. G.; Chauhan, G. D. 2017. Discovery of the first ichthyosaur from the Jurassic of India: Implications for Gondwanan palaeobiogeography. PLOS ONE 12(10): e0185851. 31 p. Riccardi, A. C. 1991. Jurassic and Cretaceous marine connections between the Southeast Pacific and Tethys. Palaeogeography, Palaeoclimatology, Palaeoecology 87:155‒189. Sander, P. M. 2000. Ichthyosauria: their diversity, distribution, and phylogeny. Paläontologische Zeitschrift 74:1–35. Sassoon, J.; Foffa, D.; Marek, R., 2015. Dental ontogeny and replacement in Pliosauridae. Royal Society Open Science 2:150384. 15 p. Shultz, M. R.; Fildani, A.; Suárez, M. E. 2003, Occurrence of the southernmost South American ichthyosaur (Middle Jurassic–Lower Cretaceous), Parque Nacional Torres del Paine, Patagonia, southernmost Chile. Palaios 18:69–73. Soto-Acuña, S.; Otero, R. A.; Alarcón, J.; Ossa-Fuentes, L.; Rojas, O. 2015. Presencia de cocodrilos marinos (Thalattosuchia: Metriorhynchidae) en la Formación Cerritos Bayos (Oxfordiano), Cuenca de Tarapacá, Región de Antofagasta. Congreso Geológico de Chile N° XIV, Actas Vol. III, pp. 690–693. Octubre 4-8, 2015, La Serena, Chile. Soto-Acuña, S.; Otero, R. A.; Orrego, R.; Salazar, C. 2016. Nuevo hallazgo de reptiles marinos en el Cretácico Inferior de Formación Lo Valdés, Cuenca Andina. V Simposio de Paleontología de Chile, Libro de Resúmenes, 63–66. Stinnesbeck, W.; Frey, E.; Rivas, L.; Pardo-Pérez, J.; Leppe, M.; Salazar, C.; Zambrano, P. 2014. A Lower Cretaceous ichthyosaur graveyard in deep marine slope channel deposits at Torres del Paine National Park, southern Chile. Geological Society of America Bulletin 126:1317–1339. Suárez, M.; Bell, C. M. 1992. The oldest South American ichthyosaur from the late Triassic of northern Chile. Geological Magazine 129: 247‒249.
71 MUSEO DE HISTORIA NATURAL Y CULTURAL DEL DESIERTO DE ATACAMA CALAMA, CHILE Suárez, M. E.; Otero, R. A. 2010. Dos nuevas localidades con presencia de ictiosaurios (Reptilia, Ichthyosauria) en el Jurásico Inferior del Norte de Chile. Actas del II Simposio Paleontología en Chile. Concepción, Chile. p. 53. Suárez, M. E.; Otero, R. A. 2011. First record of a neoselachian shark in the Jurassic of Chile. IV Congreso Latinoamericano de Paleontología de Vertebrados, San Juan, Argentina, 21 al 24 de septiembre. Ameghiniana 48: R213. Tavera, J. 1981. Ichthyosaurus de la Formación Lautaro, en el área de Manflas, Región de Atacama. Comunicaciones nº 33, Departamento de Geología, Universidad de Chile. 16 p. Tyborowski, D. 2016. A New Ophthalmosaurid Ichthyosaur from the Late Jurassic of Owadów-Brzezinki Quarry, Poland. Acta Palaeontologica Polonica 61:791–803. Wagner, A. 1852. Neu-aufgefundene Saurier-Überreste aus den lithographischen Schiefern und dem obern Jurakalke. Abhandlungen der Mathematisch-Physikalischen Classe der Königlich Bayerischen Akademie der Wissenschaften 6:661-710. Wahl, W. 2012. Salt gland structures identified in a Late Jurassic ichthyosaur, Ophthalmosaurus natans. Paludicola 8:252–262. Yin, Y-L.; Ji, C.; Zhou, M. 2021. The anatomy of the palate in Early Triassic Chaohusaurus brevifemoralis (Reptilia: Ichthyosauriformes) based on digital reconstruction. PeerJ 9: e11727. 19 p. Zittel, K.A. von. 1890. Handbuch der Palaeontologie I. Abtheilung Palaeozoologie III. Band. Vertebrata (Pisces, Amphibia, Reptilia, Aves). Verlag von R. Oldenbourg. München and Leipzig, XII + 900 pp. Zverkov, N. G.; Efimov, V. M. 2019. Revision of Undorosaurus, a mysterious Late Jurassic ichthyosaur of the Boreal Realm. Journal of Systematic Palaeontology 17:1183–1213. Zverkov, N. G.; Prilepskaya, N. E. 2019. A prevalence of Arthropterygius (Ichthyosauria: Ophthalmosauridae) in the Late Jurassic-earliest Cretaceous of the Boreal Realm. PeerJ 7: e6799. 70 p.