Phalarodon sp.

Klug, Christian, Sivgin, Timur, Miedema, Feiko, Scheffold, Beat, Reisdorf, Achim G., Stössel, Iwan, Maxwell, Erin E. & Scheyer, Torsten M., 2024, Swiss ichthyosaurs: a review, Swiss Journal of Palaeontology (31) 143 (1), pp. 1-29 : 9-24

Phalarodon sp.

Figure 7

Material: PIMUZ T1311, NMB S. Tr. 12 ( Fig. 7 ). Locality: Monte San Giorgio TI, Laufenburg AG Stratigraphic position: Besano Formation, and Lower Muschelkalk, Anisian, Middle Triassic

Short description: PIMUZ T1311 is almost complete and articulated, although the skull is somewhat disrupted, whereas NMB S. Tr. 12 displays the incomplete left premaxilla, maxilla, vomer, quadrate and dentary. NMB S. Tr. 12 lacks the supra- and subnarial processes of the premaxilla, supporting referral to Mixosauridae ( Roberts et al., 2022) . Characteristically for the genus Phalarodon ( Roberts et al., 2022) , both NMB S. Tr. 12 and PIMUZ T1311 show a mandibular heterodonty with posterior teeth being larger, and stouter with thecodont implantation.

Remarks: Te fragmentary skull from Aargau (NMB S. Tr. 12) was published by Maisch and Matzke (2005) and assigned to Phalarodon major . McGowan and Motani (2003) considered P. major to be a nomen dubium based on a non-diagnostic lectotype. Phalarodon currently has three valid species, P. atavus (revision by Liu et al., 2013), P. fraasi , and P. callawayi , with only P. atavus documented from the Muschelkalk Group. Te Laufenburg skull is here referred to Phalarodon sp. pending further revision of the Lower Muschelkalk Group forms. Brinkmann (2004) described a small specimen from Monte San Giorgio that was referred to Phalarodon sp. (PIMUZ T1311).

Hueneosauria Maisch & Matzke, 2000 Cymbospondylidae Huene, 1948

Cymbospondylus buchseri Sander, 1989

Figures 8 , 9

Material: Holotype PIMUZ T 4351 ( Fig. 8 ).

Locality: Cava Tre Fontane near Serpiano and Meride (Ticino)

Stratigraphic position: Besano Formation, Anisian, Middle Triassic

Short description: Te holotype and only referred specimen shows the anterior half of the skeleton with three-dimensionally preserved bones. Te posterior half was lost during mining. Te body length of C. buchseri can be reconstructed to about 5.5 m ( Rieppel, 2019; Sander, 1989). However, bone histology suggests that the holotype animal was still growing at time of death ( Sander, 1989). C. buchseri had a comparatively high and broad rostrum (see reconstruction in Fig. 9 ), and a long and slender body. Te caudal fin was likely poorly developed as in C. petrinus ( McGowan & Motani, 2003; Merriam, 1908).

Remarks: While the osteologically immature holotype reached only about 5.5 m, other members of the genus are estimated to have reached 17 m body length ( Sander et al., 2021). McGowan and Motani (2003) mention that the skull is also poorly ossified, which is typical for immature individuals.

As in several other ichthyosaur fossils, especially from the Jurassic ( Delsett et al., 2016; Wahl, 2009), the snout of the holotype is severely fractured. As demonstrated by Wetzel and Reisdorf (2006), ichthyosaur carcasses usually sank head-first. Te pointed rostrum would have penetrated more or less deeply into the soft sediment on impact, and the force of impact is likely to have resulted in fracturing of the delicate rostral bones ( Delsett et al., 2016; Wahl, 2009). We are unaware of other reasonable explanations of such snout deformations. To our knowledge, there is no documentation of any actualistic case of such cranial fracturing caused by an impact into the seabed. Te stomach content ( Fig. 9b, c ) of the holotype comprises arm hooks and beaks of numerous phragmoteuthid coleoids ( Brinkmann, 1997).

Merriamosauria Motani, 1999

Shastasauridae Merriam, 1895

Besanosaurus leptorhynchus Dal Sasso & Pinna, 1996

Figures 9 , 10

Material: Holotype BES SC 999, PIMUZ T 4376

( Fig. 10 ) and additional materials (see Bindellini et al., 2021).

Locality: Holotype found near Besano ( Italy), further specimens known also from localities close to Serpiano and Meride (Ticino)

Stratigraphic position: Besano Formation, Middle Triassic, Anisian

Short description: Tis ichthyosaur attained large sizes of up to 8 m body length (e.g., the strongly flattened specimen PIMUZ T 4847). Several complete skeletons of juvenile individuals ( Fig. 9 ) are available in Zurich and Milan. Te species is characterized by an elongate, rather slen- der body and a slender snout with small teeth.

Remarks: Mikadocephalus gracilirostris ( Maisch & Matzke, 1997) is a junior synonym of Besanosaurus leptorhynchus according to Bindellini et al. (2021).

Shastasauridae gen. et sp. indet.

Figures 11 , 12

Material: PIMUZ A/ III 670, 744 ( Figs. 11 , 12 ) and additional referred materials (see Sander et al., 2022).

Locality: Graubünden

Stratigraphic position: Kössen Formation (Schesaplana Member), Late Norian to Rhaetian, Triassic

Short description: Te Swiss specimens are isolated bones, teeth and disarticulated parts of skeletons including a large vertebra and several ribs ( PIMUZ A/ III 744). A fragmentary tooth ( PIMUZ A/ III 670), interpreted herein as also belonging to a shastasaurid ( Figs. 11 , 12 ), preserves a diameter of about 50 mm and had a reconstructed apicobasal height of 150 to 200 mm (see tentative reconstruction in Fig. 12a, c ). Te vertebra ( PIMUZ A/ III 744a; Fig. 11 ) associated with the ribs measures about 250 mm in diameter and suggests a body length of up to 20 m, similar to that of Shonisaurus ( Nicholls & Manabe, 2004) . Shastasauridae is famous for the giant adult body size of several of its genera and species, which belong to the largest ichthyosaurs known ( Nicholls & Manabe, 2004; Sander et al., 2021).

Remarks: Triassic ichthyosaurs are known for both their diversity and their disparity in body size. Camp (1976, 1980), Nicholls and Manabe (2004), and Kelley et al. (2022) reported giant shastasaurids from North America, which reached approximately 20 m body length. Some decades ago, remains of huge latest Triassic (Rhaetian) shastasaurids were found in the mountains of eastern Switzerland; these remains have recently been described along with other Shastasauridae vertebrae from the upper Norian-lower Rhaetian Alplihorn Member of the Kössen Formation ( Furrer, 1993; Sander et al., 2022). In contrast to Shonisaurus sikanniensis ( Nicholls & Manabe, 2004) but similar to S. popularis ( Kelley et al., 2022) , at least some Swiss shastasaurids had huge teeth ( Fig. 12 ).

Jurassic

Parvipelvia Motani, 1999

Ichthyosauridae Bonaparte, 1841

Protoichthyosaurus Appleby, 1979

Protoichthyosaurus cf. applebyi Lomax et al., 2017

Figure 13

Material: SMF 46 ( Fig. 13 ).

Locality: Frick AG, possibly also large specimens from Grellingen BL.

Stratigraphic position: Beggingen Member, Staffelegg Formation, Lower Sinemurian, Jurassic

Short description: Te Frick skull is three-dimensionally preserved but lacks much of the snout ( Maisch et al., 2008). Protoichthyosaurus is a moderate-sized ichthyosaur with robust dentition, a rostrum that is shorter than in more derived genera such as Stenopterygius or Eurhinosaurus , a dorsal region intermediate in length between, e.g., Cymbospondylus and Ophthalmosaurus , and moderately long forefins with three elements in the proximal carpal row. Protoichthyosaurus has two named species, P. applebyi and P. prostaxalis (Lomax et al., 2017) . Only two specimens of P. applebyi are known, reaching a skull length of ~ 40 cm; however, the more abundant species P. prostaxalis could reach skull lengths of 80 cm ( Lomax et al., 2019).

Remarks: Te Frick specimen was originally referred to Ichthyosaurus communis by Maisch et al. (2008). Since then, our understanding of ichthyosaur diversity from the Hettangian-Sinemurian interval has changed drastically, with specimens previously referred to Ichthyosaurus having been split into two genera and eight species (Lomax & Massare, 2017; Lomax et al., 2017). Based on the participation of the parietal in the parietal foramen, as described by Maisch et al. (2008), the Frick specimen is inconsistent with Ichthyosaurus (see Lomax et al., 2020), but Protoichthyosaurus remains a possibility. Based on the limited exposure of the maxilla ventral to the nares, the Frick skull is most likely attributable to P. cf. applebyi ( Lomax & Massare, 2018; Lomax et al., 2017, 2020). Te specimen from Frick ( Fig. 13 ) was probably much larger than documented specimens of P. applebyi , with a skull length estimated at 60 cm ( Maisch et al., 2008), but within the range of Protoichthyosaurus skulls. Isolated bones that, based on their size may also belong to this taxon, occur occasionally in other Swiss localities ( Peyer & Köchlin, 1934; Maisch et al. 2008).

Temnodontosauridae

Temnodontosaurus Lydekker, 1889

? Temnodontosaurus sp.

Figure 14

Material: NAT19310.001-0.003 ( Fig. 14 ).

Locality: Beggingen (Schaffhausen).

Stratigraphic position: Beggingen Member, Staffelegg Formation, Lower Sinemurian, Lower Jurassic

Short description: A partial caudal skeleton (NAT19310.001-0.003) was referred to? Temnodontosaurus based on the dimensions of the vertebrae. Temnodontosaurus is a large ichthyosaur (up to 15 m in length: McGowan, 1996) with robust jaws and skull. Te forefin has three digits and one postaxial accessory digit.

Remarks: NAT19310.001-0.003 was excavated by Früh (1962) in the 1960s. It is tentatively included in? Temnodontosaurus because of the large size of the vertebrae (up to 120 mm in diameter) and stratigraphic age. While the Sinemurian-aged Leptonectes solei has equally large anterior caudal vertebrae (~ 140 mm in diameter in the holotype), the vertebrae of this species are proportionately longer than those of the Schaffhausen specimen (EEM, pers. observ.), making a referral to Temnodontosaurus more plausible. Te vertebrae are on display in the Museum Allerheiligen in Schaffhausen.

Leptonectidae Maisch 1998

Eurhinosaurus Abel, 1909

Eurhinosaurus longirostris (Mantell, 1851)

Figure 15

Material: PIMUZ A/III 749 ( Fig. 15 ), on display at the Naturama in Aarau.

Locality: Staffelegg AG

Stratigraphic position: Rietheim Member, Toarcian, Jurassic

Short description: Te specimen from Staffelegg is a slightly deformed incomplete skull, which preserves the huge orbits with the sclerotic ring and the base of the very slender rostrum ( Reisdorf et al., 2011). Eurhinosaurus is one of the most remarkable ichthyosaurs because of its outstanding morphology with an extremely elongate, tooth-bearing upper jaw that is about twice as long as the lower jaw (e.g., Maisch & Matzke, 2000; McGowan & Motani, 2003); its huge orbits give the skull a mosquito-like appearance. Also, the slender body of this genus reached impressive lengths of just over 7 m ( McGowan & Motani, 2003), with long paired fins (e.g., Maisch & Matzke, 2000).

Remarks: Jobbins et al. (2024) compared this ichthyosaur with other vertebrates with extremely elongated upper or lower jaws because of its pronounced overbite (e.g., Maisch & Matzke, 2000; McGowan & Motani, 2003). Tis discrepancy in upper versus lower jaw length may be linked to “to strike and confuse prey” ( Jobbins et al., 2024: p. 11).

Parvipelvia, Unnamed clade ( Maxwell & Cortés, 2020) Hauffiopteryx Maisch, 2008

Hauffiopteryx typicus (von Huene, 1931)

Figure 16

Material: NMO 26575 ( Fig. 16 ).

Locality: Unterer Hauenstein SO

Stratigraphic position: Müsenegg Bed, Breitenmatt Member, Staffelegg Formation, Pliensbachian, Jurassic

Short description: Te specimen NMO 26575 was embedded in a quite common position with the skull vertically sticking in the sediment ( Maisch & Reisdorf, 2006a, b). Te anterior postcranium was oriented subvertically behind it. It is limited to some articulated vertebrae, neural arches, ribs, gastralia, and phalanges. Te rest of the postcranium likely came to rest on the sediment surface. Hauffiopteryx reached a body length of up to 3 m ( Maxwell & Cortés, 2020). Its skull bore a short and quite slender rostrum (upper jaw slightly longer than the lower jaw) and big eyes. Te dorsal region is moderately short and moderately slender (between Cymbospondylus and Ophthalmosaurus ). Te tail is approximately as long as the dorsal region and bears a narrow symmetrical caudal fin.

Remarks: Te specimen was originally referred to the Hettangian-Sinemurian species Leptonectes tenuirostris by Maisch and Reisdorf (2006a, b), although inconsistencies in phalangeal shape were noted. Tis aspect, in addition to details of skull morphology, led to the specimen being reassigned to the Toarcian species Hauffiopteryx typicus by Maxwell and Cortés (2020). Remarkably, the vertically embedded skull and the surrounding concretion at least partially diagenetically penetrated three ammonite zones ( Wetzel & Reisdorf, 2006). Both the posterior skull and the postcranium were exposed to scavenging over a prolonged time. Te left supratemporal bears five holes ( Fig. 16F ), which lack indications for healing. It is unclear, what made these holes, but it was quite likely post mortem, which fits with the vertically embedded skull and the posterior being exposed over a long time. Superficially, the holes resemble bite traces produced by reptile predators or scavengers (e.g., Scheyer et al., 2024), but they may as well have formed by erosion or some diagenetic process (future examination might clarify the origin of these holes). It is also noteworthy that several specimens of the minute gastropod Coelodiscus accumulated between the postcranial elements.

Baracromia Fischer et al., 2013.

Stenopterygiidae Woodward in von Zittel, 1932.

Stenopterygius Jaekel, 1904 , emend. Von Huene, 1922.

Stenopterygius sp.

Figures 17 , 18

Material: Nearly complete skeleton NMBE5014842. Bone-bearing slabs MGL 42002, 42003, 42004, 40947, 40950, 40948, 40949 ( Weidmann, 1981).

Locality: Creux de l’Ours, Teysachaux FG; Le Ruisseau du Chalevay, South of Col de Soladier, 3 km northeast of Avants/Montreux, VD; Asuel JU.

Stratigraphic position: Teysachaux FG—Soladier Member, Staldengraben-Formation, and Asuel JU—Rietheim Member, Staffelegg Formation, Toarcian, Early Jurassic.

Short description: Te skeleton NMBE5014842 from Teysachaux FG ( Fig. 17 ) is nearly complete and over 2 m long, although poorly preserved ( von Huene, 1939). A much more fragmentary specimen (MGL 42002, 42003, 42004, 40947, 40950, 40948, 40949) may also belong to Stenopterygius and was briefly described by Weidmann (1981). It comprises three vertebrae between 36 and 45 mm in diameter and remains of at least 15 ribs. It lacks clearly diagnostic bones. A nearly complete skull with three-dimensionally preserved bones in a nodule was found in a valley near Asuel ( Fig. 18 ). Te nodule with the skull is only partially prepared, and hence the assignment is somewhat uncertain. Stenopterygius is a midsized ichthyosaur with adults between 2.0 and 3.75 m in length, characterized by a long rostrum (almost as long as in Ophthalmosaurus ) with variably reduced teeth, and a moderately regionalized vertebral column.

Remarks: NMBE5014842 was acquired from the finder Joseph Cardinaux in 1870 by the Natural History Museum of the Burgergemeinde Bern for 120 Francs. In 1934, the numerous fragments of the huge C-shaped concretion were sent to Bernhard Hauff in Holzmaden, Germany, who was then considered the most experienced preparator. Von Huene (1939), also based in Germany, described this specimen, which is mainly remarkable for its geographic origin. Tis might be the source of the rumour that the skeleton might be German rather than Swiss. Furrer (1960) and Menkveld-Gfeller (1998) provided numerous lines of independent evidence that the skeleton indeed comes from the alpine equivalent of the Posidonienschiefer Formation (Soladier Mb.) in the Teysachaux region. Due to extensive reconstruction and poor preservation, the specimen cannot be referred to species level (Maisch, 2008).

Ophthalmosauria Motani, 1999

Argovisaurus Miedema et al., 2024

Argovisaurus martafernandezi Miedema et al., 2024

Figures 19 , 20 )

Material: Holotype PIMUZ A/ III 5279 .

Locality: Auenstein, Oberegg quarry AG

Stratigraphic position: Lower Acuminata beds, Hauptrogenstein Formation, Middle Jurassic, subfurcatum/ niortense zone of the Middle Bajocian ( Meyer, 1988).

Short description: Te disarticulated skull and most of the dorsal region are known based on the holotype and only known specimen; the limbs and tail are not preserved

( Fig. 20 ). With a skull length of about 1.3 m, Argovisaurus was a large early-diverging ophthalmosaurian. Its skull bore robust jaws and moderately large eyes. It appears to have been rather deep-bodied.

Remarks: Based on taphonomic evidence such as disarticulation, traces of scavenging and oyster overgrowth on a vertebra, Miedema et al. (2024) indicate that the carcass was covered by sediment after a rather long exposure time. Te excellent three-dimensional preservation of the bones permitted the reconstruction of the skull. Tis species is important because it was found in the stratigraphic interval (stage) with the poorest ichthyosaur record of the Jurassic ( Fischer et al., 2021). Additionally, the Argovisaurus holotype is the largest and most complete skeleton of the Bajocian. It is of special importance because of its position at the base of the Ophthalmosauria ( Miedema et al., 2024), the clade to which most Late Jurassic and Cretaceous ichthyosaurs belong, that originated in the early Middle Jurassic.

Platypterygiinae

Figure 21

Material: NMO-26330, -26,734 ( Fig. 21 ). Dubbed «Bornsaurier» because of its origin.

Locality: Born near Ruppoldingen SO

Stratigraphic position: Wettingen Member, Burghorn Formation, Kimmeridgian, Jurassic

Short description: Te main slab ( Fig. 22a ) preserves some of the extremely slender jaw bones, teeth, a left quadrate in lateral view, as well as vertebrae and ribs. Te tooth roots are quadrangular in cross-section, allowing referral to Platypterygiinae ( Fischer et al. 2021). Platypterygiine ichthyosaurs are characterized by broad forefins and moderate body sizes of up to 7 m in length; within the clade there is relatively high anatomical disparity.

Remarks: Generally, the post-Toarcian fossil record of ichthyosaurs is meagre in Switzerland. Te partial skeleton from the Born near Ruppoldingen (NMO-26734) is currently the only identifiable ichthyosaur from the Late Jurassic of Switzerland. Remarkably, it was kept unprepared since 1905 in the Naturmuseum Olten, where it was over many years considered to be crocodile remains. Maisch (2014) described it as Brachypterygius mordax , a presumed error since he went on to state that B. extremus and Grendelius mordax represented the same taxon, and therefore the Swiss specimen should have been referred to the senior synonym B. extremus . Because of the quadrangular tooth roots, the specimen can confidently be referred to the ophthalmosaurian subfamily Platypterygiinae , which includes Brachypterygius / Grendelius . However, several Late Jurassic taxa with quadrangular tooth roots have been documented, including B. extremus / G. mordax , G. alekseevi, Acuetzpalin carranzi, and Undorosaurus spp. (see Barrientos-Lara & Alvarado-Ortega, 2021). Tus, this character cannot be considered diagnostic at even the generic level.

Te collection of the University of Zurich also keeps some isolated bone fragments ( Fig. 21b–d ), which perhaps belong to the same taxon. Te locality further yielded remains of chondrichthyans, marine crocodiles and pliosaurids.

Cretaceous

Isolated remains have been recovered from the Cretaceous of Switzerland (see below), but to date no remains diagnostic to genus level have been described. See the section below.

Fragments unidentifiable on genus and species level Because of the fragmentary nature of the materials listed below, we refrain from providing descriptions of the entire animal.

Mixosauridae indet.

Figure 22

Material: PIMUZ A/III 175, 177, 1508, 1509 ( Fig. 23 ).

Locality: Laufenburg AG

Stratigraphic position: Lower Muschelkalk, Anisian, Middle Triassic

Short description: Te vertebrae in the collections of the University of Zurich display the characteristic slightly hexagonal outline of mixosaurid vertebrae and are of a moderately small size (up to 32 mm high).

Remarks: Von Huene (1916) described several isolated ichthyosaur vertebrae (on his plate V, some re-figured here in Fig. 22 ) stored in the collections of the Palaeontological Institute of the University of Zurich, for some of which he introduced the species “ Mixosaurus helveticus ”. McGowan and Motani (2003) follow Mazin (1983) in considering M. helveticus a nomen dubium. Centrum size and shape are reminiscent of a small mixosaurid like M. cornalianus , although this material is older than the material from the Besano Formation. A generic assignment is not possible given the lack of vertebral characters differentiating Mixosaurus and Phalarodon .

? Shastasauridae gen. et sp. indet.

Figures 23 , 24

Material: Nat19309 ( Fig. 23 ), PIMUZ A/III 4601

( Fig. 24 ).

Locality: Mining area at the slope of the Wutach valley, ca. 1 km E of Schleitheim SH.

Stratigraphic position: Upper Muschelkalk Group, Schinznach Formation, “Trochitenkalk”, Anisian.

Short description: Nat19309 is a single subcircular bone measuring about 120 × 125 mm, which was collected from scree. It was acid prepared and shows the characteristic lateral concavity of a humerus, but it could also be a coracoid. One side is slightly corroded, showing the characteristically lightly built ichthyosaur spongiosa

( Fig. 23 ).

Remarks: Te specimen is kept at the Museum zu Allerheiligen in Schaffhausen. A vertebra had been assigned to “ Pessosaurus suevicus ” and is kept in Zurich with the number PIMUZ A/III 4601 ( Fig. 24 ). “ Pessosaurus suevicus ” is a nomen dubium, with type material consistent with? Shastasauridae indet. ( Maisch & Matzke, 2000); the referred vertebra is consistent with this assessment.

Figures

Fig. 7 Phalarodon sp. (von Huene, 1916), NMB S.Tr.12, Wellenkalk of Schwaderloch AG; skull fragment preserving parts of the dentary (bottom), premaxilla,maxilla, vomer, and quadrate (see Maisch & Matzke, 2005: Fig.1). The slab also bears the bivalves Plagiostoma lineata (ribbed) and Hoernesia socialis. Photo modified after Loïc Costeur (Basel)

Fig. 8 Cymbospondylus buchseri Sander, 1989, PIMUZ T 4351, Holotype, Besano Fm., Anisian,Middle Triassic,Cava Tre Fontane TI, on display in the Natural History Museum of the University of Zurich. a The entire skeleton. b Detail showing the fins and parts of the thorax with stomach content. c Detail of the stomach content with some phalanges and ammonoids (probably not part of the stomach content)

Fig. 9 Besanosaurus leptorhynchus Dal Sasso & Pinna, 1996 (left) and Cymbospondylus buchseri Sander,1989 (right), Anisian,Middle Triassic; skeletal reconstructions by Beat Scheffold; Besanosaurus after Nosotti and Teruzzi (2008: Fig. 12B) and Bindellini et al., (2024:Fig. 11)

Fig. 10 Besanosaurus leptorhynchus Dal Sasso & Pinna,1996, PIMUZ T 4376,one of the most complete specimens of this species

Fig. 11 Shastasauridae sp. A. of Sander et al. (2022), dorsal vertebra, PIMUZ A/III 744a, Rhaetian, Schesaplana Member, Fil da Stidier ridge,Filisur, Grisons.a Dorsal; b posterior; c lateral, d ventral views.Figures labelled with 2 were retrodeformed using PhotoShop

Fig. 12 Fragmentary tooth (base and minor parts of the crown) of a giant shastasaurid PIMUZ A/III 670, Rhaetian Schesaplana Member, Crachenhorn Mountain, Davos-Monstein, Grisons. a Lingual;b apical; c mesial or distal; d basal views. In a and c, a possible tooth outline is reconstructed (grey surface)

Fig. 13 Protoichthyosaurus cf. applebyi Lomax et al., 2017, SMF 46, incomplete skull, dorsal view, upper Beggingen Member (“Arietenkalk”), semicostatum ammonite zone, Gruhalde,Frick AG

Fig. 14?Temnodontosaurus sp., NAT19310.001-.003, Staffelegg Formation, Lower Sinemurian, Beggingen (Schaffhausen).The vertebral column is on display in the Museum Allerheiligen SH.Photo by Urs Weibel

Fig. 15 Eurhinosaurus longirostris (Mantell, 1851), PIMUZ A/III 749, Rietheim Member,Toarcian,Early Jurassic, Staffelegg (Aargau), photos were taken by Alexandra Wegmann (Zurich)

Fig. 16 Hauffiopteryx typicus (von Huene, 1931), NMO 26575,Pliensbachian, Unterer Hauenstein (Solothurn). A dorsal; B left lateral;C ventral; D right lateral; E posterior view of the articulated skull. F Detail showing potential bite marks on the supratemporal. G Postcranial elements including about ten thoracal vertebrae, neural arches,thoracal ribs and a few pectoral fin elements

Fig. 17 Stenopterygius sp., NMBE5014842 (inventarized in Bern, on display in Fribourg), Soladier Member, Staldengraben-Formation,Toarcian, Teysachaux FG,photo by Hans-RÜdiger Siegel

Fig. 18?Stenopterygius sp., Rietheim Member, Staffelegg-Formation, Toarcian,Asuel JU, photo by Bernhard Hostettler

Fig. 19 Argovisaurus martafernandezi Miedema et al., 2024, PIMUZ A/III 5279, Bajocian, Auenstein, Oberegg quarry (Aargau)

Fig. 20 Argovisaurus martafernandezi Miedema et al., 2024, skeletal reconstruction by Beat Scheffold

Fig. 21 Skeletal remains of Platypterygiinae indet. from the Kimmeridgian of the Born near Ruppoldingen SO. a NMO-26734, disarticulated partial skeleton. b to d PIMUZ A/III 863, isolated bones (skull remains and a vertebra)

Fig. 22 Isolated vertebra centra of “Mixosaurus helveticus” (a–o) and Cymbospondylus sp. (p–s), Wellendolomit Member, Lower Muschelkalk Group, Laufenburg AG.a–h PIMUZ A/III 177, showing all sides and the external moulds of both facets.i–m PIMUZ A/III 1509. o PIMUZ A/III 1508, vertically sectioned vertebra.p–s PIMUZ A/III 175

Fig. 23 Humerus or coracoid of a?shastasaurid from the Trochitenkalk (lower part of the Upper Muschelkalk Group), Nat19309,NE of Schleitheim. Left:after preparation. Right: unprepared

Fig. 24 Vertebra of a?shastasaurid (“Pessosaurus suevicus”), PIMUZ A/III 4601,Trochitenkalk (lower part of the Upper Muschelkalk Group),Auhald, Schleitheim. a, c Lateral; b dorsal; e ventral; d, f anterior and posterior views