Harpoceratinae

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Harpoceratinae
Temporal range: Upper Pliensbachian to lower Bajocian [1]
Hildoceratidae - Harpoceras subplanatum.JPG
Fossil shell of Harpoceras subplanatum from Isère (France), on display at Galerie de paléontologie et d'anatomie comparée in Paris
Scientific classification Red Pencil Icon.png
Kingdom: Animalia
Phylum: Mollusca
Class: Cephalopoda
Subclass:† Ammonoidea
Order:† Ammonitida
Family:† Hildoceratidae
Subfamily:† Harpoceratinae
Neumayr, 1875
Genera

at least 9, see text

Synonyms

Polyplectinae Venturi, 1981

Harpoceratinae is an extinct subfamily of cephalopods belonging to the family Hildoceratidae. Ammonites of this subfamily had involute and compressed shells with strong keels. Keel might be rarely missing, but this is considered to be an abnormality. This has been observed both in Cleviceras and Harpoceras and called as genus Monestieria , which is now known to be invalid (into this invalid genus were added also abnormal unkeeled specimens of genus Protogrammoceras ). Another example is Pseudolioceras , whose unkeeled specimen was used as type for description of invalid genus Praehaploceras . Oxyconic forms of this subfamily ( Polyplectus and Sphenarpites ) does not have any keel. Ribs were single, but in some genera also bifurcating with shapes from sigmoidal to falcate. Sometimes, shell can have only striate ribs or is smooth (Sphenarpites and older specimens of Eleganticeras and Ovaticeras ). Tubercules are rare. Dimorphism is known in some genera and it is observable mostly in size. Macrochons can be 4, to 6 times larger than microconchs. As an example, macroconchs of Pseudolioceras are more than 150mm in diameter, while adult microconchs are only 35-50mm. There are big size differences even within dimorphs. Specimens ca be 2, or sometimes even 3 times bigger than other specimens of same dimorph. [1]

Contents

Genera

At least 9 genera is considered to be members of this subfamily. [1] [2] This number can be increased, as some authors might consider valid some genera, which are by other authors considered to be synonyms of these 9. For example, Maconiceras is sometimes listed within this subfamily, [3] while by other authors, it is considered to be a synonym of Harpoceras . [1]

Osperleioceras bicarinatum Zieten 1831 Osperleioceras bicarinatum.png
Osperleioceras bicarinatum Zieten 1831

Sometimes, more genera is referred to this subfamily, as some authors does not recognize validity of subfamily Protogrammoceratinae. [3] [5] Neolioceratoides , which has been included within Protogrammoceratinae and was also considered to be a synonym of Lioceratoides is now member of Hildoceratinae, which is reason why it is not listed below. [6] This would include genera:

Taffertia taffertensis Guex 1973 Taffertia taffertensis.png
Taffertia taffertensis Guex 1973

In 1981 a new subfamily has been erected and named Polyplectinae, which is sometimes considered to be a synonym of Harpoceratinae, [1] but sometimes it is still used as valid taxa. [7] Following genera are part of this subfamily: [8]

Distribution

Polyplectus pluricostatus Haas 1913 Polyplectus pluricostatum.png
Polyplectus pluricostatus Haas 1913

Fossils of this subfamily have been found in the layers of upper Pliensbachian - lower Bajocian age. Distribution for subfamily is worldwide. All genera have been found in northern hemisphere, but only fossils of Harpoceras, Osperleioceras and Polyplectus comes also from southern hemisphere. [1]

Timeline and evolution

If Protogrammoceratinae shall be considered a valid subfamily, then Harpoceratinae might be of polyphyletic origin with at least 2 main lineages, both evolving from Protogrammoceratinae. First one started in upper Pliensbachian (Spinatum zone) when Tiltoniceras evolved from Lioceratoides , or Protogrammoceras . In Toarcian, during lower part of Exaratum subzone of Falciferum zone it evolved into Eleganticeras, which soon gave rise to Cleviceras. Polyplectus evolved from this genera.

Second lineage originated from Protogrammoceras, which has been predecessor for Harpoceras. Three genera evolved from this genus - Osperleioceras (from Harpoceras subplanatum), Ovaticeras (from Harpoceras falciferrum) and Pseudolioceras (probably also from Harpoceras falciferrum). Pseudolioceras is the only known member of this subfamily that lived also in middle Jurassic. Last common ancestor of both these lineages might have been Protogrammoceras that lived in Spinatum zone of Pliensbachian or sooner. Some authors (Knyazev et al., 2007) does not recognize validity of Cleviceras and place its species still in Harpoceras, while they considers Harpoceras falciferrum to be descended from Harpoceras exaratum (in most of recent literature is this species member of genus Cleviceras). Origin of the remaining 2 genera is probably unknown. Taffertia lived in Falciferrum zone of early Toarcian (maybe only in Exaratum subzone). Sphenarpites is known from single specimen that comes from early Toarcian. [1] [9] [10] [11]

Approximate timeline of Harpoceratinae genera. Sphenarpites is not shown, as its occurrence in time is not exactly known (it is lower Toarcian). Taffertia might have died out in Exaratum subzone which, if true, would mean it would have only about 1/3 of existence time. Harpoceratinae.svg
Approximate timeline of Harpoceratinae genera. Sphenarpites is not shown, as its occurrence in time is not exactly known (it is lower Toarcian). Taffertia might have died out in Exaratum subzone which, if true, would mean it would have only about 1/3 of existence time.

Related Research Articles

<i>Dactylioceras</i> Genus of molluscs (fossil)

Dactylioceras was a widespread genus of ammonites from the Lower Jurassic period, approximately 180 million years ago (mya).

Abbasites is an extinct genus of ammonites from the early Middle Jurassic epoch, included in the ammonitid family Erycitidae.

Zugodactylites is an extinct genus of ammonite cephalopod from the lower Toarcian epoch of the Lower Jurassic, ammonite zone Fibulatum. Its fossils are found in Europe, Russia and Canada.

Haploceratoidea, formerly Haplocerataceae, is an extinct superfamily of ammonoid cephalopods belonging to the Ammonitida that unites three families, Strigoceratidae, Oppeliidae, and Haploceratidae, listed below.

<span class="mw-page-title-main">Hildoceratidae</span> Extinct family of molluscs

Hildoceratidae is a family of ammonoid cephalopods from the Lower Jurassic, lower Pliensbachian to lower Bajocian substages, generally with strongly ribbed, involute shells. They are combined with the Hammatoceratidae, Graphoceratidae, and Sonniniidae to make up the Hildoceratoidea.

<span class="mw-page-title-main">Dactylioceratidae</span> Extinct family of ammonites

The family Dactylioceratidae comprises Early Jurassic ammonite genera with ribbed and commonly tuberculate shells that resembled later Middle Jurassic stephanoceratids and Upper Jurassic perisphinctids. Shells may be either evolute or involute.

<i>Harpoceras</i> Genus of molluscs (fossil)

Harpoceras is an extinct genus of ammonite belonging to the family Hildoceratidae. These cephalopods existed in the Jurassic period, during the Toarcian age from the Falciferum zone to the Commune subzone of the Bifrons zone. They were fast-moving nektonic carnivores.

<i>Taffertia</i> Genus of molluscs (fossil)

Taffertia is an extinct genus of cephalopod belonging to the family Hildoceratidae. These cephalopods existed in the Jurassic period, during Toarcian age in the Falciferum zone and possibly only in Exaratum subzone. Its fossils were found in Canada, Morocco, Algeria and Italy

Ovaticeras is an extinct genus of cephalopod belonging to the family Hildoceratidae. These cephalopods existed in the Jurassic period, during upper Pliensbachian and lower Toarcian. Its fossils were found in Europe, North Africa and possibly also in Canada and Vietnam. It might have evolved from Harpoceras falciferum and died out without leaving any descendants.

<i>Osperleioceras</i> Genus of molluscs (fossil)

Osperleioceras is an extinct genus of cephalopod belonging to the family Hildoceratidae. These cephalopods existed in the Jurassic period, during Toarcian stage. Its fossils were found in Europe and South America. First species of this genus, Osperleioceras bicarinatum has evolved in what is now France from Harpoceras subplanatum.

<i>Cleviceras</i> Genus of molluscs (fossil)

Cleviceras is an extinct genus of cephalopod belonging to the family Hildoceratidae. These cephalopods existed in the Jurassic period, during Toarcian and possibly even uppermost Pliensbachian age. Sometimes, it is considered to be a synonym of Eleganticeras.

<i>Prodactylioceras</i> Extinct genus of ammonites

Prodactylioceras is genus of ammonite that lived during the Pliensbachian stage of early Jurassic. It has evolved from Reynesocoeloceras, but maybe not directly, but through Bettoniceras. Its fossils were found in Europe, Asia and North America.

<i>Catacoeloceras</i> Extinct genus of ammonites

Catacoeloceras is a genus of ammonite that lived during Middle Toarcian stage of early Jurassic. Members of this genus existed from Bifrons Subzone of Bifrons Zone to Variabilis Zone. Their fossils were found in Europe, northern Africa, Asia, North America and South America. It has evolved from Porpoceras.

Nodicoeloceras is genus of ammonite that lived during early to middle Toarcian stage of early Jurassic. Members of this genus existed from Exaratum Subzone of Falciferum Zone to Commune subzone of Bifrons Zone. Their fossils were found in Europe, northern Africa, Asia, North America and South America. It has probably evolved from Dactylioceras (Orthodactylites) or Kedonoceras and gave rise to Mesodactylites.

<span class="mw-page-title-main">Dactylioceratinae</span> Extinct subfamily of ammonites

The subfamily Dactylioceratinae comprises early Jurassic ammonite genera that lived during Upper Pliensbachian to Upper Toarcian stage. These dactylioceratids existed from Margaritatus ammonite Zone, when they have evolved from Reynesocoeloceratinae and died out in Variabilis Zone without leaving any descendants.

Neolioceratoides is genus of ammonites that lived during the Pliensbachian and Toarcian stages of early Jurassic. It has been considered to be a synonym of Lioceratoides, but cladistic analysis has shown, that this genus is not only valid, but they even belong to different subfamily, as Lioceratoides belongs to Harpoceratinae. Their fossils were found in Europe and northern Africa.

<span class="mw-page-title-main">Hildoceratinae</span> Extinct subfamily of molluscs

Hildoceratinae is an extinct subfamily of cephalopods belonging to the family Hildoceratidae. Ammonites of this subfamily had shells with elliptical or quadrate whorl section with keel or tricarinate, bisulcate venter. Ribs were variable, from falcate to strongly angled and from fine to strong. They can be interrupted by spiral groove in midlateral part of the shell. While some species can be smooth, strongly ribbed ones can have tubercules. Microconchs have short lapplets that is in its shape similar to the shape of growth lines in spiral midlateral groove.

<i>Orthildaites</i> Genus of molluscs (fossil)

Orthildaites is a genus of ammonites that lived during the lower Toarcian stage of early Jurassic, during Falciferum subzone.

<i>Mercaticeras</i> Genus of molluscs (fossil)

Mercaticeras is an extinct genus of ammonites belonging to the family Hildoceratidae.

<span class="mw-page-title-main">Federico Venturi</span> Italian paleontologist (1940–2020)

Federico Venturi was an Italian paleontologist. He is internationally known as a specialist of Early Jurassic ammonites.

References

  1. 1 2 3 4 5 6 7 M. K. Howarth 2013. Treatise on Invertebrate Paleontology, Part L, Revised, Volume 3B, Chapter 4: Psiloceratoidea, Eoderoceratoidea, Hildoceratoidea.
  2. 1 2 Marc BÉCAUD (2006) LES HARPOCERATINAE, HILDOCERATINAE ET PARONICERATINAE DU TOARCIEN DE LA VENDÉE ET DES DEUX-SÈVRES (FRANCE).
  3. 1 2 Bardin Jérémie, Rouget Isabelle, Benzaggagh Mohamed, Theodor Fürsich Franz, Cecca Fabrizio (2015). "Lower Toarcian (Jurassic) ammonites of the South Riffian ridges (Morocco): systematics and biostratigraphy". Journal of Systematic Palaeontology. 13 (6): 471–501. doi:10.1080/14772019.2014.937204. S2CID   129583207.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  4. ↑ CV Ullmann, N Thibault, M Ruhl, SP Hesselbo, C Korte (2014). "Effect of a Jurassic oceanic anoxic event on belemnite ecology and evolution" (PDF). Proceedings of the National Academy of Sciences. 111 (28): 10073–6. Bibcode:2014PNAS..111S0073U. doi: 10.1073/pnas.1320156111 . PMC   4104856 . PMID   24982187.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  5. ↑ Kamata Yoshihito, Mizobe Shin-Ichi, Sato Tadashi (2003). "An Early Jurassic ammonite from a limestone conglomerate in the Kuzu Complex of the Ashio Belt". Paleontological Research. 7 (3): 185–194. doi: 10.2517/prpsj.7.185 . S2CID   130917025.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  6. ↑ Bardin, J., Rouget, I., & Cecca, F. (2016). The phylogeny of Hildoceratidae (Cephalopoda, Ammonitida) resolved by an integrated coding scheme of the conch. Cladistics.
  7. ↑ Kovács, Z. "Lower Toarcian Ammonitida fauna and biostratigraphy of the Gerecse Mountains (Hungary).—." Fragmenta Palaeontologica Hungarica 29 (2012): 1-48.
  8. ↑ Venturi F, Bilotta M (2008) New data and hypotheses on early Jurassic ammonite phylogeny. Rev Paléobiol 27:859–901
  9. ↑ M. K. Howarth 1992. HILDOCERATIDAE IN THE LOWER JURASSIC OF BRITAIN
  10. ↑ J. Rai, S. Jain 2013. Pliensbachian nannofossils from Kachchh: Implications on the earliest Jurassic transgressive event on the western Indian margin
  11. ↑ В. Г. Князев, Р. В. Кутыгин, О. А. Мельник, 2007. БИОХРОНОЛОГИЧЕСКАЯ ШКАЛА ТОАРА-РАННЕГО БАЙОСА СЕВЕРО-ВОСТОКА АЗИИ ПО ХАРПОЦЕРАТИНАМ (АММОNОЮЕА) (V. G. Knyazev, R. V. Kutygin, O. A. Meľnik, 2007, A Toarcian–Early Bajocian biochronological scale for northeastern Asia, based on Harpoceratinae (Ammonoidea))(in Russian)
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