Early ontogeny, anomalous growth, and healed injuries in the Silurian nautiloid Ophioceras Barrande – Implications for hatching and the autecology of the Tarphycerida

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F00025798%3A_____%2F16%3A00000080" target="_blank" >RIV/00025798:_____/16:00000080 - isvavai.cz</a>

Nalezeny alternativní kódy

RIV/00023272:_____/16:N0000057

Výsledek na webu

<a href="http://www.geology.cz/bulletin/contents/art1596" target="_blank" >http://www.geology.cz/bulletin/contents/art1596</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.3140/bull.geosci.1596" target="_blank" >10.3140/bull.geosci.1596</a>

Jazyk výsledku

angličtina

Název v původním jazyce

Early ontogeny, anomalous growth, and healed injuries in the Silurian nautiloid Ophioceras Barrande – Implications for hatching and the autecology of the Tarphycerida

Popis výsledku v původním jazyce

Our study of the early ontogeny of the Silurian Ophioceras has led to the revision of the current concept that many juvenile tarphycerids possessed a coiled conch upon hatching and thus resembled adults in habit as is in extant Nautilus. In fact, there is no evidence that any Early Palaeozoic coiled nautiloid possessed an embryonic conch exceeding half a whorl. A change in conch coiling, occasionally accentuated by a dorsolateral groove analogous to the nepionic constriction and the appearance of conspicuous growth anomalies indicate that, after hatching, Ophioceras possessed a cap-shaped, slightly curved conch, usually approximately a quarter whorl long. A hatchling thus differed substantially from the likely nektonic late juveniles with coiled conchs and their obliquely oriented aperture as in Nautilus. A relatively large first phragmocone chamber and very short body chamber possibly resulted in positive buoyancy and a planktonic habit of hatchlings. The embryonic conch size is highly variable and the height of the first chamber varies between 1.2–2.6 mm. Changes in sculpture across the embryonic/juvenile conch boundary are sometimes gradual, but frequently, hatching is manifested by an abrupt increase in growth line spacing and the appearance of longitudinal ridges. The cicatrix is here documented in the Tarphycerida for the first time. A distinct chamber length decrease, commonly present close to the end of the first whorl, is not linked with hatching. Anomalous conch structures in Ophioceras including healed injuries, atypical shapes of ribs, atypical courses of septa and pits occurring in late juvenile growth stages are described in the light of the autecology of Ophioceras and the determination of early post-embryonic growth anomalies

Název v anglickém jazyce

Early ontogeny, anomalous growth, and healed injuries in the Silurian nautiloid Ophioceras Barrande – Implications for hatching and the autecology of the Tarphycerida

Popis výsledku anglicky

Our study of the early ontogeny of the Silurian Ophioceras has led to the revision of the current concept that many juvenile tarphycerids possessed a coiled conch upon hatching and thus resembled adults in habit as is in extant Nautilus. In fact, there is no evidence that any Early Palaeozoic coiled nautiloid possessed an embryonic conch exceeding half a whorl. A change in conch coiling, occasionally accentuated by a dorsolateral groove analogous to the nepionic constriction and the appearance of conspicuous growth anomalies indicate that, after hatching, Ophioceras possessed a cap-shaped, slightly curved conch, usually approximately a quarter whorl long. A hatchling thus differed substantially from the likely nektonic late juveniles with coiled conchs and their obliquely oriented aperture as in Nautilus. A relatively large first phragmocone chamber and very short body chamber possibly resulted in positive buoyancy and a planktonic habit of hatchlings. The embryonic conch size is highly variable and the height of the first chamber varies between 1.2–2.6 mm. Changes in sculpture across the embryonic/juvenile conch boundary are sometimes gradual, but frequently, hatching is manifested by an abrupt increase in growth line spacing and the appearance of longitudinal ridges. The cicatrix is here documented in the Tarphycerida for the first time. A distinct chamber length decrease, commonly present close to the end of the first whorl, is not linked with hatching. Anomalous conch structures in Ophioceras including healed injuries, atypical shapes of ribs, atypical courses of septa and pits occurring in late juvenile growth stages are described in the light of the autecology of Ophioceras and the determination of early post-embryonic growth anomalies

Druh

J_x - Nezařazeno - Článek v odborném periodiku (Jimp, Jsc a Jost)

CEP obor

DB - Geologie a mineralogie

OECD FORD obor

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Projekt

<a href="/cs/project/GA14-16124S" target="_blank" >GA14-16124S: Zpřesnění chronostratigrafie spodního siluru: návrh nových mezinárodních stratotypů (GSSP) stupňů aeron a homer</a><br>

Návaznosti

P - Projekt vyzkumu a vyvoje financovany z verejnych zdroju (s odkazem do CEP)

Rok uplatnění

2016

Kód důvěrnosti údajů

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Název periodika

Bulletin of Geosciences

ISSN

1214-1119

e-ISSN

—

Svazek periodika

91

Číslo periodika v rámci svazku

2

Stát vydavatele periodika

CZ - Česká republika

Počet stran výsledku

36

Strana od-do

331-366

Kód UT WoS článku

000379623400008

EID výsledku v databázi Scopus

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