09 April 2016:
We just published two articles in a special issue of Arthropod Structure & Development, entitled “Fossils as Living Beings”. Both deal with the development of fossil achelatan lobsters and the evolutionary implications.
In the first paper, we present the ontogeny of tenera Oppel, 1862 from the 150 million years old limestones of southern Germany:
Haug, J. T. & Haug, C. 2016. “Intermetamorphic” developmental stages in 150 million-year-old achelatan lobsters – The case of the species tenera Oppel, 1862. Arthropod Structure & Development 45, 108–121.
In comparison with extant species, the specimens investigated in this study possess a mixture of larval and post-larval characters. We could reconstruct parts of the development of this species, which does not exist in modern achelatan lobsters anymore. In modern species there is a strong developmental jump instead of the gradual development we see in the fossil species, which is the best preserved developmental sequence we know from a fossil achelatan lobster to date.
The specimens of tenera Oppel, 1862 obviously all represent immature individuals, and the corresponding adult is not known yet. Originally, this species has been described as Palinurina tenera. However, it is not clear if this species and the only other species of Palinurina, P. longipes, are sister species as a proper comparison is not possible as there are no corresponding developmental stages. Therefore, we prefer to use either tenera Oppel, 1862 as a neutral species name or Achelata tenera (an approach suggested by other authors) as the species is for sure an achelatan lobster. Most of the material was kindly provided by private collectors; hence the study emphasises again the importance of hobby palaeontology. The paper was published here.
In the second article, we use fossil developmental data to elucidate the evolution of slipper lobsters:
Haug, J. T., Audo, D., Charbonnier, S., Palero, F., Petit, G., Abi Saad, P. & Haug, C. 2016. The evolution of a key character, or how to evolve a slipper lobster. Arthropod Structure & Development 45, 97–107.
Modern slipper lobsters have a characteristic shovel-like antenna. This special shape has evolved from an originally elongate antenna as that of spiny lobsters. We investigated different fossils from the Cretaceous limestones of Lebanon and compared them with other fossil as well as extant species, also including different developmental stages. With this, we were able to reconstruct the stepwise evolution of the shovel-shaped antenna of modern slipper lobsters. The article is available here.
Additionally, we are happy to announce that Carolin got her project proposal granted by the German Research Foundation (DFG). She will now be funded for investigating body organisation in chelicerates for 3 years.
17 February 2016:
Recently, two articles of our PhD students Marie Hörnig and Christina Nagler were published. Both papers deal with arthropods in amber.
The article of Marie is about brood care in the fossil record:
Hörnig, M. K., Sombke, A., Haug, C., Harzsch, S. & Haug, J. T. 2016. What nymphal morphology can tell us about parental investment – a group of cockroach hatchlings in Baltic Amber documented by a multi-method approach. Palaeontologia Electronica 19(1), art. 5A, 20 pp.
In the here presented piece of amber, probably Baltic Amber and thus 40–50 million years old, 13 cockroach nymphs are enclosed. With a combination of different imaging methods we could show the morphological details in three dimensions. In this way, it became clear that the nymphs all have the same size and show different characters of freshly hatched cockroaches, for example, a lack of pigmentation. Furthermore, we found indications that the parents probably also took care of these nymphs after hatching. Characters pointing to such a brood care behaviour are the missing eyes and the still underdeveloped antennae in the nymphs, which means that these animals were probably not developed far enough yet to survive on their own. The paper is freely available and can be found here.
Christina describes in her article the first fossil report of larvae of parasitic isopods:
Serrano-Sánchez, M. L., Nagler, C., Haug, C., Haug, J. T., Centeno-García, E. & Vega, F. J. 2016. The first fossil record of larval stages of parasitic isopods: cryptoniscus larvae preserved in Miocene amber. Neues Jahrbuch für Geologie und Paläontologie, Abhandlungen 279(1), 97–106.
This study was possible through a collaboration with colleagues from Mexico led by Francisco Vega, with whom we already published project results successfully in the past. Again many thanks for the possibility to collaborate on this project! All investigated amber pieces stem from Chiapas in Mexico and are thus ca. 23 million years old. Enclosed in the amber were 7 specimens of very small, just about 450 µm to ca. 700 µm long,so-called Cryptoniscus larvae. These represent the later larval stage of certain parasitic isopods (Epicaridea). With this, our find is also the first fossil record of larvae of peracarid crustaceans as well as of body fossils of the isopod group Epicaridea; of the latter only the typical swellings induced by the adults on the host animals were known so far. The paper can be found here.
26 December 2015:
At the end of the year, three new articles from our team got published, all with the aid of our students and all in Palaeodiversity. One of them even made it onto the cover page:
Haug, J. T. & Rudolf, N. R. 2015. A nisto larva of an Eocene slipper lobster (Neoscyllarida). Palaeodiversity 8, 113–119.
The fossil investigated in this study, a ca. 50 million years old slipper lobster, was documented with up-to-date documentation methods. In this way, we were able to reveal different morphological details, which have not been available for the original description. Especially ventral details as, for example, those of the legs or the sternum became discernible by applying macro-autofluorescence. The overall morphology argues for the specimen representing a last larval stage, a so-called nisto. With this, it would be just the second nisto in the fossil record. The article is freely available and can be downloaded here.
In a second paper we present new data on fossil mantis shrimp larvae:
Haug, C., Wiethase, J. H. & Haug, J. T. 2015. New records of Mesozoic mantis shrimp larvae and their implications on modern larval traits in stomatopods. Palaeodiversity 8, 121–133.
In the last few years we have already described different types of mantis shrimp larvae from the Solnhofen limestones. The first of these larvae did not receive any name at that time, as we had only very little data based on a single specimen. Now we reinvestigated the original specimen and could also study an additional one. Based on these new data, we could describe the larvae as a new species, Gigantosculda ehrlichfeckei. Additionally, we could also describe new details the feeding and raptorial apparatus of larvae of another species, Spinosculda ehrlichi. Based on these character, we were able to reconstruct parts of the life habits of this species and aspects of the evolution of mantis shrimps from the Jurassic until today. The freely available paper can be found here.
In the third article we describe a new species of a fossil roach-like insect:
Dittmann, I. L., Hörnig, M. K., Haug, J. T. & Haug, C. 2015. Raptoblatta waddingtonae n. gen. et n. sp. – an Early Cretaceous roach-like insect with a mantodean-type raptorial foreleg. Palaeodiversity 8, 103–111.
The new species, Raptoblatta waddingtonae, originates from the 115 million years old Crato formation in Brazil. The fossil shows a general cockroach-like habitus, but additionally possesses a pair of raptorial appendages morphologically similar to those of modern praying mantises. The details of the raptorial appendage morphology point to a sister group relationship of the newly described species with praying mantises. The paper can be freely downloaded here.
These three publications represent each the first publication of one of our current or past team members Nicole Rudolf, Joris Wiethase and Isabel Dittmann. We are very happy about this, congratulations!