paleontologist Aleksandr A. Mironenko

About me

My name is Aleksandr Mironenko, I am a paleontologist and paleobiologist. I have been interested in nature and fossils since my childhood. Although for most kids the dinosaurs are the most popular ancient creatures, I always have been more interested in invertebrate fossils such as fossilized seashells. The first fossil seashells for my collection (they were Devonian brachiopods) I found in gravel on the roads of Moscow, my hometown, when I was about 10 years old.

Nevertheless, my way to the paleontological science was long and winding and for a long time paleontology was only my hobby. I graduated from university in 2003 with a BA and specialist degree (analogue of a masters degree in the old Russian system) in environmental sciences. In the first year in the university, the training included a short course of geology with elements of paleontology and with excursions to various fossil localities. After I found out where well-preserved fossils can be collected, I became an active fossil collector and amateur paleontologist. A large number of easily accessible localities of the Jurassic age in the vicinity of Moscow and in the city itself influenced the choice of my main object of collecting and later of my research - ammonites. A few years later, while still an amateur paleontologist, I completed a bachelor's degree in computer sciences. For several years I worked as a web-programmer and in my spare time made two paleontological web-sites:, dedicated to fossils which are located in the wall decorating material of the stations of Moscow Metro, and – mix of a forum, social network and a fossil record database for amateurs and specialists in the paleontology.

Collecting ammonites and fossil nautiloids led me to reading paleontological literature - I tried to read all the articles and books on cephalopod paleobiology (especially on ammonoid paleobiology) which I could find. Thanks to the Internet and help of my friends - professional paleontologists, I had access to both classic books and modern journal articles and gradually realized that among ammonites in my collection there are some paleobiological features that had not been described in literature. Since 2014 I began to describe these findings in my own publications. Thus I went from being a reader to a writer of scientific articles and became a self-educated paleontologist.

Currently, I work at the Geological Institute of the Russian Academy of Sciences ( as a researcher. My professional interests concentrate mainly on Jurassic and Cretaceous ammonoids, but cover all fossil cephalopods, including various Paleozoic nautiloids. I am interested in various aspects of the evolution, paleoecology, and paleobiology of the fossil nautiloids and ammonoids: the structure and evolution of their jaw apparatus, muscular system, and siphuncle tissues, their growth, reproduction, sexual dimorphism, etc. I like to go and take part in excavations and to find cephalopod shells for future research. I alternate between the writing of scientific papers and popular publications and maintains my websites.

My scientific accounts

Most recent articles

Mironenko Aleksandr (2021) Early Palaeozoic Discinocarina: a key to the appearance of cephalopod jaws. Lethaia, in press

Early Palaeozoic Discinocarina: a key to the appearance of cephalopod jaws.

Cephalopoda is the only class of molluscs in which virtually all its modern representatives have a pair of powerful jaws. There is little doubt that jaws have contributed to the evolutionary success of cephalopods, but their origin still remains a mystery. Though cephalopods appeared at the end of the Cambrian, the oldest unequivocal jaws have been reported to date from the Late Devonian, though they were initially interpreted as phyllopod crustaceans of the suborder Discinocarina. After their relation with ammonoids was proven, they were considered as opercula, and only later their mandibular nature was recognized and widely accepted. Finds of discinocarins from Silurian deposits are still considered as opercula of ammonoid ancestors ‐ nautiloids of the order Orthocerida. However, according to modern ideas, there is no place within their soft body for the location of such large opercula. Moreover, the repeated appearance of very similar structures in the same evolutionary line at least twice, but in different places of the body and for different purposes seems highly improbable. A new hypothesis is proposed herein, in which the Silurian fossils, earlier assigned to Discinocarina, are not specialized opercula, but protective shields, to defend orthocerids not from the predators, but from their own prey. The chitinous plates around the mouth likely appeared in the Silurian orthocerids for protection from such damage and later, during Silurian and Devonian, most likely gradually evolved into the jaws.

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Mironenko Aleksandr, Mitta Vasiliy (2020) On new records of Cephalopod jaws from the Upper Bajocian (Middle Jurassic) of the Northern Caucasus (Russia, Karachay-Cherkessia). Paleontological Journal, 5, 38–48

On new records of Cephalopod jaws from the Upper Bajocian (Middle Jurassic) of the Northern Caucasus (Russia, Karachay-Cherkessia).

New finds of cephalopod jaw apparatuses from the upper part of the Niortense Zone and the lower part of the Parkinsoni Zone (Upper Bajocian) from the interfluve of the Kuban and Urup rivers (Northern Caucasus) are described. Two isolated valves of aptychi which are considered to be ammonoid lower jaws are assigned to the superfamilies Haploceratoidea and Stephanoceratoidea. Two upper jaws likely belonged to ammonites with aptychus-type jaw apparatus (Ammonitida). The seven anaptychus-type jaws are assigned to the orders Phylloceratida and Lytoceratida. A well-preserved upper jaw of coleoid affinity is described for the first time from the Mesozoic of the Northern Caucasus.

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Schwarzhans Werner, Mironenko Aleksandr (2020) First teleost otoliths from the Late Jurassic of Russia. Neues Jahrbuch für Geologie und Paläontologie-Abhandlungen, 295 (1), 1-8

First teleost otoliths from the Late Jurassic of Russia.

This is the first record of Late Jurassic (Volgian) otoliths from the boreal province of Russia. Two new species– Palealbula korchinskyi n. sp. and Palealbula moscoviensis n. sp. – are described representing otoliths of putative stem-albuliform affinities of unresolved familiar position. The phylogeny of Palealbula and the supposedly related genus Protalbula is discussed in the light of the new findings presented in this article. Both genera are shown to represent a common faunal element in the early evolutionary phase of teleosts during the Late Jurassic and Early Cretaceous.

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Mironenko Aleksandr (2020) A hermit crab preserved inside an ammonite shell from the Upper Jurassic of Central Russia: implications to ammonoid palaeoecology. Palaeogeography, Palaeoclimatology, Palaeoecology, 537, 109397

A hermit crab preserved inside an ammonite shell from the Upper Jurassic of Central Russia: implications to ammonoid palaeoecology.

The discovery of a hermit crab (superfamily Paguroidea) preserved in the likely immature shell of an ammonite, Craspedites nekrassovi is reported from the Upper Jurassic of Moscow, Russia. This is the oldest undoubtable symmetrical hermit crab to date which is known from non-reefal environments. This new occurrence combined with the documentation of numerous sublethal and lethal injuries on ammonite shells in the same beds (probably produced by such paguroids), all suggest that the hermit crabs not only lived in ammonite shells but also hunted these animals. The proportion of damaged shells (including healed ones) varies in different Upper Jurassic ammonite genera from 1.2% in Kachpurites up to 9.3% in Craspedites. Among damaged Kachpurites only 6.25% survived attacks whereas among Craspedites the percentage of survivors was 87.5%. These data imply that Craspedites likely lived near the sea bottom and often encountered hermit crabs, whereas Kachpurites likely lived in the water column.

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Mironenko Aleksandr (2020) Endocerids: suspension feeding nautiloids? Historical Biology, 32 (2), 281-289

Endocerids: suspension feeding nautiloids?

For a long time all extinct cephalopods of the subclass Nautiloidea were considered as ecological analogues of the Recent Nautilus. Recently this view has been rejected: it is now known that among the nautiloids there were not only demersal predators but also epipelagic animals whose life-style and reproduction differed from those of the Nautilus. However, the habits of some nautiloid orders is still poorly understood. One of the most enigmatic cephalopods is the Early Paleozoic nautiloid order Endocerida. Endocerids differ from other nautiloids: they reached gigantic sizes (up to 9 meters), had a wide siphuncle tube and were widespread and numerous during the Ordovician. Since they were an important component of many Ordovician ecosystems, without the understanding of their habits and feeding strategies a correct reconstruction of these ecosystems is impossible. Until now, endocerids have been considered as dominant apex predators, however, this assumption is based on an analogy with the Nautilus mode of life, while the features of the structure of endocerid shells do not confirm this idea and furthermore contradict it. In this article, a new hypothesis is proposed and debated: according to it, the endocerids were planktotrophic cephalopods and the largest of them were giant suspension feeders.

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