Moltrasio Formation

{{Short description|Geological formation in Italy and Switzerland}}

{{Infobox rockunit

| name = Moltrasio Formation

| image = Calcare di Moltrasio Campo dei Fiori.JPG

| caption = Outcrop

| type = Geological formation

| age = Middle Sinemurian-Lower Pliensbachian
~{{fossil range|196|188}}

| period = Sinemurian

| prilithology = Limestone

| otherlithology =

| namedfor = Moltrasio

| namedby = Antonio StoppaniStoppani A. (1857). Studi geologici e paleontologici sulla

Lombardia. 461 pp. Tipografia Turati, Milano

| year_ts = 1857

| region = Lombardy

| country = Italy, Switzerland

| coordinates = {{coord|46.0|N|9.1|E|display=inline,title}}

| paleocoordinates = {{coord|33.2|N|15.6|E|display=inline}}

| unitof = Monte Generoso Basin

| subunits = Osteno Outcrop

| underlies = Domaro Formation

| overlies = *Saltrio Formation

Sedrina Limestone

| thickness = 200 m

| extent =

| area =

| map = {{Location map+ | Italy#Italy Lombardy

| relief = 1

| width = 250

| float = center

| places =

{{Location map~ | Italy#Italy Lombardy

| lat_deg = 46.0

| lon_deg = 9.1

| mark = Blue pog.svg

| marksize = 12

}}

The Moltrasio Formation also known as the Lombardische Kieselkalk Formation is a geological formation in Italy and Switzerland. This Formation mostly developed in the Lower or Middle Sinemurian stage of the Lower Jurassic, where on the Lombardian basin tectonic activity modified the current marine and terrestrial habitats.{{cite journal |last1=Muttoni |first1=G. |last2=Erba |first2=E. |last3=Kent |first3=D. V. |last4=Bachtadse |first4=V. |title=Mesozoic Alpine facies deposition as a result of past latitudinal plate motion |journal=Nature |date=2005 |volume=434 |issue=7029 |pages=59–63 |doi=10.1038/nature03378 |pmid=15744297 |bibcode=2005Natur.434...59M |s2cid=4316860 |url=https://www.nature.com/articles/nature03378|hdl=2434/30440 |hdl-access=free }} Here it developed a series of marine-related depositional settings, represented by an outcrop of 550–600 m of grey Calcarenites and Calcilutites with chert lenses and marly interbeds, that recovers the Sedrina, Moltrasio and Domaro Formations. This was mostly due to the post-Triassic crisis, that was linked locally to tectonics.{{cite journal |last1=Jadoul |first1=F. |last2=Galli |first2=M. T. |title=The Hettangian shallow water carbonates after the Triassic-Jurassic biocalcification crisis: The Albenza Formation in the western Southern Alps |journal=Rivista Italiana di Paleontologia e Stratigrafia |date=2008 |volume=114 |issue=3 |pages=453–470 |url=https://www.researchgate.net/publication/257482739 |access-date=2 May 2023}} The Moltrasio Formation is considered a continuation of the Sedrina Limestone and the Hettangian Albenza Formation, and was probably a shallow water succession, developed on the passive margin of the westernmost Southern Alps.{{cite journal |last1=Sarti |first1=M. |last2=Bosellini |first2=A. |last3=Winterer |first3=E. L. |title=Basin Geometry and Architecture of a Tethyan Passive Margin, Southern Alps, Italy: Implications for Rifting Mechanisms: Chapter 13: African and Mediterranean Margins |journal=AAPG Special Volumes |date=1992 |volume=115 |issue=5 |pages=241–258 |url=https://archives.datapages.com/data/specpubs/history2/data/a115/a115/0001/0200/0241.htm |access-date=2 May 2023}} It is known due to the exquisite preservation observed on the Outcrop in Osteno, where several kinds of marine biota have been recovered.{{cite journal |last1=Pinna |first1=G. |title=Exceptional preservation in the Jurassic of Osteno. |journal=Philosophical Transactions of the Royal Society of London B: Biological Sciences |date=1985 |volume=311 |issue=1148 |pages=171–180 |doi=10.1098/rstb.1985.0149 |bibcode=1985RSPTB.311..171P |url=https://royalsocietypublishing.org/doi/10.1098/rstb.1985.0149 |access-date=2 May 2023|url-access=subscription }}

Fossils

= Exceptional fossilization =

File:Parco delle Gole della Breggia Motrasio-Kalk mit Bruch1.jpg

Apart from the Eocene of Monte Bolca, the Sinemurian of Osteno is the only fossil deposit in Italy in which soft bodies are preserved. The Osteno site was discovered in 1964. It was recovered from a series of {{convert|6|m|ft}} package of fine laminated, gray, spongiolitic, micritic limestone.{{cite book |last1=Pinna |first1=G. |chapter=Die Fossillagerstätte im Sinemurium (Lias) von Osteno, Italien |title=Europäische Fossillagerstätten |date=2000 |volume=3 |issue=7 |pages=91–136 |doi=10.1007/978-3-642-57198-5_13 |isbn=978-3-642-62975-4 |chapter-url=https://link.springer.com/chapter/10.1007/978-3-642-57198-5_13 |access-date=2 May 2023}} Coroniceras bisulcatum allowed to date the outcrop as the Bucklandi zone, lower Sinemurian. The outcrop is a good documentation of a particularly complete fauna and flora of the Lower Jurassic which is not exactly common in the Southern Alps. The Osteno outcrop, part of the formation, is worldwide known due to the exceptional preservation of mostly marine biota, including rare fossilized components, helping to understand the ecosystems of the local Sinemurian margin of the Monte Generoso Basin.{{cite book |last1=Bottjer |first1=D. J. |last2=Etter |first2=W. |last3=Tang |first3=C. M. |last4=Hagadorn |first4=J. W. |title=Exceptional fossil preservation: a unique view on the evolution of marine life |date=2002 |publisher=Columbia University Press |page=421 |isbn=9780231102544 |url=http://cup.columbia.edu/book/exceptional-fossil-preservation/9780231102551 |access-date=2 May 2023}} The high local variety of fossils found is most likely due to unique conditions of preservation, where phosphatized soft tissues have not been observed in any fish or polychaetes, but they are common in crustaceans (33%) and also occur in a smaller percentage of teuthids (14%).{{cite journal |last1=Wilby |first1=P. R. |last2=Briggs |first2=D. E. |title=Taxonomic trends in the resolution of detail preserved in fossil phosphatized soft tissues |journal=Geobios |date=1997 |volume=30 |issue=8 |pages=493–502 |doi=10.1016/S0016-6995(97)80056-3 |bibcode=1997Geobi..30..493W |url=https://www.sciencedirect.com/science/article/pii/S0016699597800563 |access-date=2 May 2023|url-access=subscription }} Soft part preservation through phosphatization in this deposit includes the muscles and branchia of Crustaceans, fish tissues, and the digestive tracts of coleoids, polychaetes, and nematodes. These fossils are interpreted as having been preserved in a stagnant, restricted basin with anoxic conditions likely within the sediment pore waters.

{{multiple image

| align = center

| perrow = 2/2

| total_width = 950

| image1 = BACINO LOMBARDO SYN-RIFT LATE TRIAS-LIAS.png

| image2 = Ostenocaris vs Ostenoteuthis Osteno.png

| caption1 = Structural scheme illustrating the syn-rift setting of the western Lombardian Basin during late Triassic and early Jurassic (most of the early jurassic terms belong to the calcare di Moltrasio and secondarily to Calcare di Domaro and Rosso Ammonitico Lombardo). The approximated location in the context of Osteno lagerstätte is indicated. References in the image.

| caption2 = Artistic reconstruction of a hypothetical scene related to the Osteno deposit (Sinemurian-Lower Jurassic). Thylacocephalan Ostenocaris cypriformis are hunting cephalopods (Ostenoteuthis) and other arthropods (Coleia, Phlyctisoma). Two feed on the carcass of a conspecific. The sediment, which is very rich in siliceous sponge spicules, indicates that these forms were common and formed true “grasslands” on the seabed. The shark-like Palaeospinax pinnai passes in the background.

}}

=Nematoida=

class="wikitable" align="center"

Genus

! Species

! Material

! Location

! Notes

! Images

Eophasma{{cite journal |last1=Arduini |first1=P. |last2=Pinna |first2=G. |last3=Teruzzi |first3=G. |title=Eophasma jurassicum ngn sp., a new fossil nematode of the Sinemurian of Osteno in Lombardy |journal=Atti della Società italiana di scienze naturali e del museo civico di storia naturale di Milano |date=1983 |volume=124 |issue=1–2 |pages=61–64}}

E. jurasicum

Six specimens with soft parts

Osteno Outcrop

A nematode, type member of the family Eophasmidae inside Desmoscolecida.{{cite book |last1=Poinar |first1=G.O. |title=The Evolutionary History of Nematodes: As revealed in stone, amber and mummies. |date=2011 |publisher=Nematology Monographs and Perspectives. 9. Brill Publishers |isbn=9789047428664}} A rare find, since nematode fossils are absent in most Mesozoic marine rocks.

200px

=Annelida=

class="wikitable" align="center"

Genus

! Species

! Material

! Location

! Notes

! Images

Melanoraphia{{cite journal |last1=Arduini |first1=P. |last2=Pinna |first2=G. |last3=Teruzzi |first3=G. |title=Melanoraphia maculata ngn sp., a new fossil polychaete of the Sinemurian of Osteno in Lombardy |journal=Atti della Società italiana di scienze naturali e del museo civico di storia naturale di Milano |date=1982 |volume=123 |issue=4 |pages=462–468 |url=https://biostor.org/reference/267295 |access-date=2 May 2023}}

M. maculata

Eleven specimens, complete with soft parts

Osteno Outcrop

A polychaete, member of the group Phyllodocemorpha with incertae sedis assignation, suggested to be a member of Lumbrineridae.

200px

=Crustacea=

Genus ! Species ! Material ! Location ! Notes ! Images
class="wikitable" align="center"
Aeger{{cite journal \|last1=Pinna \|first1=G. \|title=Decouverte d'une nouvelle faune a crustaces du Sinemurien inferieur dans la region du Lac Ceresio (Lombardie, Italie) \|journal=Atti Soc. It. Sci. Nat. Museo Milano \|date=1967 \|volume=106 \|issue=4 \|pages=183–185}}{{cite journal \|last1=Garassino \|first1=A. \|last2=Teruzzi \|first2=G. \|title=The genus Aeger Münster, 1839 in the Sinemurian of Osteno in Lombardy (Crustacea, Decapoda) \|journal=Atti della società italiana di scienze naturali e del museo civico di storia naturale di Milano \|date=1990 \|volume=131 \|issue=5 \|pages=105–136 \|url=https://www.biodiversitylibrary.org/part/325031 \|access-date=2 May 2023}} \| A. foesteri A. muensteri A. robustus A. rostrospinatus A. elongatus A. macropus \| Multiple specimens fairly preserved \| Osteno Outcrop \| A decapod, type member of the family Aegeridae. This genus is the most abundant local crustacean, and was a shrimp-like creature that was probably necrophagous. \| 200px
Coleia{{cite journal \|last1=Pinna \|first1=G. \|title=Due nuovi esemplari di Coleia vialiii Pinna, del Sinemuriano inferiore di Osteno in Lombardia (Crustacea Decapoda) \|journal=Ann. Mus. St. Nat. Genova \|date=1969 \|volume=77 \|issue=12 \|pages=626–632}}{{cite journal \|last1=Teruzzi \|first1=G. \|title=The genus «Coleia» Broderip, 1835 (Crustacea, Decapoda) in the Sinemurian of Osteno in Lombardy \|journal=Atti della Società italiana di Scienze naturali e del Museo Civico di Storia naturale di Milano \|date=1990 \|volume=131 \|issue=4 \|pages=85–104 \|url=https://www.researchgate.net/publication/317827805 \|access-date=2 May 2023}}{{cite journal \|last1=Duffin \|first1=C. J. \|title=Ostenoselache stenosoma ngn sp., a new neoselachian shark from the Sinemurian (Early Jurassic) of Osteno (Lombardy, Italy) \|journal=Società Italiana di Scienze Naturali \|date=1998 \|volume=9 \|issue=7 \|pages=1–27 \|url=http://mmtk.ginras.ru/pdf/DUFFIN,%20C.J.%201998.pdf \|access-date=2 May 2023}} \| C. vialiii C. medilerranea C. cf. antiqua C. pinnnai \| Multiple specimens fairly preserved \| Osteno Outcrop \| A decapod, type member of the family Coleiidae. Probably a bottom dweller predatory crustacean. \| 200px
Eryma{{cite journal \|last1=Devillez \|first1=J. \|last2=Charbonnier \|first2=S. \|title=Review of the Early and Middle Jurassic erymid lobsters (Crustacea: Decapoda) [Révision des Érymides (Crustacea: Decapoda) du Jurassique inférieur et moyen] \|journal=Bulletin de la Société géologique de France \|date=2019 \|volume=190 \|issue=1 \|pages=121–134 \|doi=10.1051/bsgf/2019005 \|s2cid=196643332 \|doi-access=free }} \| E. sinemuriana \| 41 specimens, fairly preserved \| Osteno Outcrop \| A decapod, type member of the family Erymidae. The species was originally identified as Pustulina sinemuriana. \|
Glyphea \| G. tricarinata \| 137 complete and fragmentary specimens \| Osteno Outcrop \| A decapod, type member of the family Erymidae. The species was originally identified as Pustulina sinemuriana. \|
Mecochirus{{cite journal \|last1=Garassino \|first1=A . \|title=The family Erymidae Van Straelen, 1924 and the superfamily Glypheoidea Zittel, 1885 in the Sinemurian of Osteno in Lombardy \|journal=AAI Soc. It. Sci.RWT. Museo Civ. Stor. Mu. Milano. Milano \|date=1996 \|volume=135 \|issue=11 \|pages=333–373\| url=https://biostor.org/reference/267182\|access-date=2 May 2023}} \| M. germari \| 81 complete and fragmentary specimens, \| Osteno Outcrop \| A decapod, member of the family Mecochiridae. Rather rare compared to other local crustacean genera. \|thumb
Ostenosculda{{Cite journal \|date=2023 \|title=Another piece in the puzzle of mantis shrimp evolution – fossils from the Early Jurassic Osteno Lagerstätte of Northern Italy \|journal=Comptes Rendus Palevol \|language=en \|volume=22 \|issue=2 \|pages=17–31\|url=https://sciencepress.mnhn.fr/en/periodiques/comptes-rendus-palevol/22/2\|access-date=2 May 2023}} \| O. teruzzii \| Single Specimen fairly preserved \| Osteno Outcrop \| A mantis shrimp \|
Palaeastacus{{cite journal \|last1=Devillez \|first1=J. \|last2=Charbonnier \|first2=S. \|title=The genus Eryma Meyer, 1840 (Crustacea: Decapoda: Erymidae): new synonyms, systematic and stratigraphic implicationsLe genre Eryma Meyer, 1840 (Crustacea: Decapoda: Erymidae): nouveaux synonymes, implications systématique et stratigraphique \|journal=Bulletin de la Société géologique de France \|date=2017 \|volume=188 \|issue=3 \|pages=1–15 \|url=https://pubs.geoscienceworld.org/sgf/bsgf/article/188/3/15/521307/The-genus-Eryma-Meyer-1840-Crustacea-Decapoda \|access-date=2 May 2023}} \| P. meyeri \| Multiple specimens fairly preserved \| Osteno Outcrop \| A decapod, member of the family Erymidae. The species was originally included in the genus Eryma as E. meyeri, although the specimens reveal morphological characters diagnostic of Palaeastacus. \|
Phlyctisoma \| P. sinemuriana \| 10 specimens, in a fairly good state of preservation \| Osteno Outcrop \| A decapod, type member of the family Erymidae. The species was originally identified as Pustulina sinemuriana. \|
Pseudoglyphea \| P. ancylochelis \| 7 complete specimens, in a fairly good state \| Osteno Outcrop \| A decapod, member of the family Litogastroidae. Probably a bottom dweller predatory crustacean. \|
Teruzzicheles{{Cite journal \|last1=Audo \|first1=Denis \|last2=Charbonnier \|first2=Sylvain \|date=2022-12-28 \|title=Teruzzicheles popeyei, an early Sinemurian polychelid lobster from the Osteno Lagerstätte (Italy) \|url=http://www.schweizerbart.de/papers/njgpa/detail/306/102494/Teruzzicheles_popeyei_an_early_Sinemurian_polychel?af=crossref \|journal=Neues Jahrbuch für Geologie und Paläontologie - Abhandlungen \|language=en \|volume=306 \|issue=3 \|pages=187–194 \|doi=10.1127/njgpa/2022/1103 \|s2cid=254820598 \|issn=0077-7749\|url-access=subscription }} \| T. popeyei \| Various specimens fairly preserved \| Osteno Outcrop \| A decapod belonging to the family Polychelidae \|

=Xiphosurida=

class="wikitable" align="center"

Genus

! Species

! Material

! Location

! Notes

! Images

Ostenolimulus{{Cite journal|last1=Lamsdell |first1=J. C. |last2=Teruzzi |first2=G. |last3=Pasini |first3=G. |last4=Garassino |first4=A. |title=A new limulid (Chelicerata, Xiphosurida) from the Lower Jurassic (Sinemurian) of Osteno, NW Italy |year=2021 |journal=Neues Jahrbuch für Geologie und Paläontologie - Abhandlungen |volume=300 |issue=1 |pages=1–10 |doi=10.1127/njgpa/2021/0974 |s2cid=234814276 }}

O. latus

A nearly complete specimen

Osteno Outcrop

A horseshoe crab, member of the family Limulidae. This genus represents the oldest Jurassic limulid and only the second xiphosuran known from Italy. Also indicates that this family were a diverse and widespread clade during the Jurassic.

=Thylacocephala=

class="wikitable" align="center"

Genus

! Species

! Material

! Location

! Notes

! Images

Ostenocaris{{cite journal |last1=Arduini |first1=P. |last2=Pinna |first2=G. |last3=Teruzzi |first3=G. |title=Ostenocaris nom. nov. pro Ostenia |journal=Atli Del/A Societcl Iraliwzn di Sc: Ienze Naturali e del Museo Civico di Storia Naturale di Milano, Miiano |date=1984 |volume=125 |issue=1–2 |page=48 |url=https://biostor.org/reference/267789}}{{cite journal |last1=Arduini |first1=P. |last2=Pinna |first2=G. |last3=Teruzzi |first3=G. |title=Il giacimento sinemuriano di Osteno in Lombardia |journal=Palaeontology, Essential of Historical Geology. Mucchi, Modena |date=1982 |volume=134 |issue=2 |pages=495–522}}

O. cypriformis

Multiple specimens, complete and incomplete

Osteno Outcrop

A thylacocephalan, type member of the family Ostenocarididae inside Conchyliocarida. It is the most common fossil of the formation, and the main identified thylacocephalan from the formation.{{cite journal |last1=Pinna |first1=G. |last2=Arduini |first2=P. |last3=Pesarini |first3=C. |last4=Teruzzi |first4=G. |title=Some controversial aspects of the morphology and anatomy of Ostenocaris cypriformis (Crustacea, Thylacocephala) |journal=Earth and Environmental Science Transactions of the Royal Society of Edinburgh |date=1985 |volume=76 |issue=2–3 |pages=373–379 |doi=10.1017/S0263593300010580 |bibcode=1985EESTR..76..373P |s2cid=85401617 |url=https://www.cambridge.org/core/journals/earth-and-environmental-science-transactions-of-royal-society-of-edinburgh/article/abs/some-controversial-aspects-of-the-morphology-and-anatomy-of-ostenocaris-cypriformis-crustacea-thylacocephala/F8AAAC4984486CE91A7EA317614B6F31 |access-date=2 May 2023|url-access=subscription }}

200x200px

=Cephalopoda=

Genus ! Species ! Material ! Location ! Notes ! Images
class="wikitable" align="center"
Arietites \| A. bucklandi \| Shells \| Osteno outcrop \| An ammonitidan, type member of the family Arietitidae inside Psiloceratoidea. The main ammonite identified locally. \|
Angulaticeras \| A. sp. \| Shells \| Osteno outcrop \| An ammonitidan, member of the family Schlotheimiidae inside Psiloceratoidea. It was not the most abundant ammonite, but was rather common. \|
Coroniceras \| C. bisulcatum \| Shells \| Osteno outcrop \| An ammonitidan, member of the family Arietitidae inside Psiloceratoidea. It was less common than other ammonites, although index for some locations. \|
Ectocentrites \| E. sp. \| Shells \| Osteno outcrop \| An ammonitidan, member of the family Lytoceratidae inside Lytoceratina. It was not the most abundant ammonite, but was rather common. \|
Ostenoteuthis{{cite journal \|last1=Pinna \|first1=Ð. \|title=Rinvenimento di un raro cefalopode coleoideo nel giacimento sinemuriano di Osteno in Lombardia \|journal=Atti de la SocietaÁ Italiana di Scienze Naturali e del Museo Civico di Storia Naturale di Milano \|date=1972 \|volume=113 \|issue=1 \|pages=141–149}}{{cite journal \|last1=Garassino \|first1=A. \|last2=Donovan \|first2=D. T. \|title=A new family of coleoids from the Lower Jurassic of Osteno, Northern Italy \|journal=Palaeontology \|date=2000 \|volume=43 \|issue=6 \|pages=1019–1038 \|doi=10.1111/1475-4983.00160 \|bibcode=2000Palgy..43.1019G \|s2cid=129455509 \|url=https://www.researchgate.net/publication/229813495 \|access-date=2 May 2023\|doi-access=free }} \| O. siroi \| Several specimens with decent preservation \| Osteno outcrop \| A coleoid, type member of the family Ostenoteuthidae. A unique group of coeloids, only found at this location. Coleoids with ten arms each bearing pairs of hooks, Ostenoteuthis measure between 18 and 30 cm length. \| 200px
Oxynoticeras \| O. oxynotum \| Shells \| Osteno outcrop \| An ammonitidan, type member of the family Oxynoticeratidae inside Ammonitida. It was not the most abundant ammonite, but was rather common. \|
Uncinoteuthis \| U. cuvieri \| An incomplete specimen consisting of the arm crown only \| Osteno outcrop \| A coleoid, member of the family Ostenoteuthidae. A unique group of coeloids, only found at this location. \| 200px

= Echinoderms =

Genus ! Species ! Material ! Location ! Notes ! Images
class="wikitable" align="center"
Hispidocrinus{{cite journal \|last1=Jaselli \|first1=L. \|title=Reappraisal of the Lower Jurassic crinoid fauna of Lombardy (Italy): insights on regional museum collections \|journal=Bollettino della Società Paleontologica Italiana \|date=2021 \|volume=60 \|issue=2 \|page=112 \|url=https://www.researchgate.net/publication/354507218 \|access-date=19 October 2023}} \| H. scalaris \| Multiple ossicles \| Pradalunga \| An Crinoidean, member of the family Isocrininae inside Isocrinida. \|
Isocrinus \| I. spp. \| Multiple ossicles \| Ubiale - Clanezzo \| An Crinoidean, member of the family Isocrininae inside Isocrinida. \|
Millericrinus \| M. cf. adneticus \| Multiple ossicles \| M. di Grone \| An Crinoidean, member of the family Millericrinidae inside Millericrinida. \|
Palaeocoma \| P. milleri \| Multiple specimens \| Ubiale - Clanezzo \| An ophiuridan, member of the family Ophiodermatidae inside Ophiodermatina. Extant tropical species like Ophioderma are benthic predators and scavengers that show the same short spines seen in Palaeocoma. \| 200px

=Hemichordata=

class="wikitable" align="center"

Genus

! Species

! Material

! Location

! Notes

! Images

Megaderaion{{cite journal |last1=Arduini |first1=P. |last2=Pinna |first2=G. |last3=Teruzzi |first3=G. |title=Megaderaion sinemuriense n. g. n. sp., a new fossil enteropneust of the Sinemurian of Osteno in Lombardy |journal=Atti della Società Italiana di Scienze Naturali e del Museo Civico di Storia Naturale in Milano |date=1981 |volume=122 |issue=2 |pages=104–108 |url=https://biostor.org/reference/267277 |access-date=2 May 2023}}

M. sinemuriense

A nearly complete specimen with soft tissue

Osteno Outcrop

An acorn worm, member of the family Harrimaniidae inside Enteropneusta. This genus was probably benthic, linked with burrowing systems.

|File:Saccoglossus.jpg]]

=Chondrichthyes=

Genus ! Species ! Material ! Location ! Notes ! Images
class="wikitable" align="center"
Hybodontiformes \| Indeterminate \| Teeth \| Osteno Outcrop \| A shark, member of the family Hybodontiformes. \|
Myriacanthidae \| Gen et sp. nov \| Virtually complete skull with associated parts of the branchial skeleton \| Osteno Outcrop \| A chimaerid, member of the family Myriacanthidae inside Chimaeriformes. \|
Ostenoselache \| O. stenosoma \| One complete articulated specimen \| Osteno Outcrop \| An euselachiian, type member of the family Ostenoselachidae inside Elasmobranchii. A unique genus of shark, only found in the Osteno Formation. With an elongated eel-shaped morphology, the specimens found measure at least 240 mm in length, with a neurocranium with a long, complex rostrum. It has been suggested it was an animal able to produce electric shocks, probably to kill prey. \| 200px
Palaeospinax{{cite journal \|last1=Duffin \|first1=C. J. \|title=Palaeospinax pinnai n. sp., a new Palaeospinacid shark from the Sinemuvian (Lower Jurassic) of Osteno (Lombardy, Italy) \|journal=Atti della Società italiana di scienze naturali e del museo civico di storia naturale di Milano \|date=1987 \|volume=128 \|issue=1 \|pages=185–202}} \| P. pinnai \| A single specimen in four contiguous pieces and including parts of the dentition and squamation \| Osteno Outcrop \| A shark, type member of the family Palaeospinacidae inside Synechodontiformes. Open water swimmer. \|
Squaloraja{{cite journal \|last1=Duffin \|first1=C. J. \|title=A myriacanthid holocephalan (Chondrichthyes) from the Sinemurian (Lower Jurassic) of Osteno (Lombardy, Italy) \|journal=Atti della Società italiana di scienze naturali e del museo civico di storia naturale di Milano \|date=1991 \|volume=132 \|issue=23 \|pages=293–308 \|url=https://biostor.org/reference/267139 \|access-date=3 May 2023}}{{Cite journal \|last1=Duffin \|first1=Christopher J. \|last2=Garassino \|first2=Alessandro \|last3=Pasini \|first3=Giovanni \|date=2023 \|title=Squaloraja; Riley 1833 (Holocephala: Squalorajidae) from the Lower Jurassic of Osteno Konservat-Lagerstätte (Como, NW Italy) \|journal=Natural History Sciences \|volume=10 \|issue=1 \|doi=10.4081/nhs.2023.642 \|s2cid=258822179 \|issn=2385-0922\|doi-access=free }} \| S. sp. \| One complete articulated specimen \| Osteno Outcrop \| A chimaerid, type member of the family Squalorajidae inside Squalorajoidei. This genus belongs to a lineage of ray-like chimaeras. \| 200px

=Actinopterygii=

Genus ! Species ! Material ! Location ! Notes ! Images
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Cosmolepis?{{cite journal \|last1=Duffin \|first1=C. J. \|last2=Patterson \|first2=C. \|title=I Pesci Fossili di Osteno: una Nuova Finestra sulla Vita del Giurassico Inferiore \|journal=Paleocronache \|date=1993 \|volume=34 \|issue=2 \|pages=18–38 \|url=https://www.researchgate.net/publication/259952765 \|access-date=3 May 2023}}{{Cite journal \|last=Franceschi \|first=Fabio \|last2=Marrama \|first2=Giuseppe \|last3=Carnevale \|first3=Giorgio \|date=2024 \|title=The enigmatic “palaeoniscoid” fishes from the Lower Jurassic (Sinemurian) of the Southern Alps (Osteno, Como, Italy) \|url=https://www.paleoitalia.it/wp-content/uploads/2024/06/Paleodays-2024-Abstract-Book_DEF.pdf#page=33 \|journal=Paleodays \|volume=XXIV \|issue=4 \|pages=62}} \| C. ornatus? \| MSNM V617, complete specimen \| Osteno Outcrop \| A primitive actinopterygiian, member of the order Palaeonisciformes. A late surviving representative of the family. The specimens may not represent members of the genus. \|thumb
Dapedium \| D. sp. \| MSNM V630, caudal fin with associated scales \| Osteno Outcrop \| A primitive actinopterygiian, type member of the family Dapediidae inside Holostei. Probably a Coral Environment wanderer. \|thumb
Furo \| F. ("Eugnathus") sp. \| MSNM V659, skull & anterior truncal body \| Osteno Outcrop \| A primitive actinopterygiian, type member of the family Furidae inside Ionoscopiformes. An enlongated Gar-alike taxon. \|thumb
Pholidophorus \| P. cf.bechei \| MSNM V621, complete specimen MSNM V556, isolated complete skull Multiple referred specimens \| Osteno Outcrop \| A primitive actinopterygiian, type member of the family Pholidophoridae inside Teleostei. Open water swimmer, probably forming schools. It is the main fish recovered on the formation. \|thumb
Pholidolepis \| P. sp. \| MSNM V409, complete specimen MSNM V594, isolated complete skull Multiple referred specimens \| Osteno Outcrop \| A primitive actinopterygiian, member of the family Pholidophoridae inside Teleostei. Open water swimmer, probably forming schools. \|thumb
Palaeonisciformes? \| Indeterminate \| MSNM V618-19, skull & toracic section specimen Other 3 Specimens \| Osteno Outcrop \| Primitive actinopterygiians, suggested to be members of the order Palaeonisciformes. The features inferred to refer this specimens aren't enough to confirm the family association. \|
Peripeltopleurus?{{Cite journal \|last1=Franceschi \|first1=F. \|last2=Marramà \|first2=G. \|last3=Carnevale \|first3=G. \|date=2023 \|title=Reassessment of a putative peltopleurid fish from the Sinemurian (Lower Jurassic) of Osteno (Como, Italy): preliminary results \|url=https://iris.unito.it/bitstream/2318/1935931/1/Franceschi%2C%20Marram%C3%A0%20%26%20Carnevale%20-%20Abstract%20Book%20Paleodays%202023-56.pdf \|journal=PALEODAYS-Abstract Book. XXIII Edizione delle Giornate di Paleontologia-2023 \|volume=23 \|issue=1 \|pages=51}} \| P. sp. \| MSNM V659, almost complete specimen lacking the tail \| Osteno Outcrop \| A primitive actinopterygiian, member of the family Peltopleuridae inside Neopterygii. Probably represents the only known Jurassic survivor of the order Peltopleuriformes \|thumb

=Sarcopterygii=

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Genus

! Species

! Material

! Location

! Notes

! Images

Undina

U. (Holophagus) cf. gulo

MSNM V587, isolated scales

Osteno Outcrop

A Coelacanth, member of the family Latimeriidae inside Coelacanthiformes. Isolated 20 mm scales of coelacanths analogous to the genus Holophagus are quite frequent on the Osteno deposits, suggesting a taxon up to 75 cm long.

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=Plants=

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Genus

! Species

! Material

! Location

! Notes

! Images

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Brachyphyllum{{Cite journal |last=Sordelli |first=F. |date=1896 |title=Flora liasica ed infraliasica |url=http://storage.lib.uchicago.edu/pres/2014/pres2014-0241.pdf |journal=Flora fossilis Insubrica. Studi sulla vegetazione di Lombardia durante i tempi geologici |pages=38-55}}

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B. saportum
B. spp.

|style="background:#D1FFCF;" |Branched Shoots

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Osteno Outcrop
Dintorni di Moltrasio

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A coniferophytan, member of the family Cheirolepidiaceae inside Pinopsida.

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style="background:#D1FFCF;" |Clathropteris

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C. platyphylla

|style="background:#D1FFCF;" |Fronds

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Carate-Lario

|style="background:#D1FFCF;" |A Fern, member of the family Dipteridaceae

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style="background:#D1FFCF;" |Ctenopteris

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C. grandis

|style="background:#D1FFCF;" |Fronds

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Moltrasio

|style="background:#D1FFCF;" |A Fern, member of the family Polypodiaceae

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Equisitites{{cite journal |last1=Bonci |first1=M. C. |last2=Vanucci |first2=G. |title=I vegetali sinemuriani di Osteno (Lombardia) |journal=Atti della Società italiana di scienze naturali e del museo civico di storia naturale di Milano |date=1986 |volume=127 |issue=2 |pages=107–127}}

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E. bunburyanus

| style="background:#D1FFCF;" |Stems

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Osteno Outcrop

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A Horsetail, member of the family Equisetaceae inside Equisetales. A freshwater-related plant, that grew as fast as modern bamboo on tropical settings.

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style="background:#D1FFCF;" |Lomatopteris

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