Mecoptera, Bittacidae

[Quetzalcoatlus]

Dear forum,

I've visited recently the magnific endless expositions of the Naturistorisches Museum Wien (Vienna natural history museum).

Almost all fossils were identified here, but there are some that don't. Usually I don't photograph the latter ones but this one was exciting for me as it belongs to a group of insects (still extant) that I like a lot.

The fossil come from Liaoning, China.

Size is about the same than modern-day Bittacus.

Any suggestion of genus and species, please?

Thanks!

[Mainefossils]

Hello @Quetzalcoatlus! Looks like a very interesting museum. 

 

I believe that @oilshale would be able to help with this more - I have a very limited knowledge on fossil insects, though I do enjoy collecting modern representatives. In my opinion, I think that it would be extremely difficult to identify this insect more specifically, based on a couple reasons. First, one of the main reasons they go unidentified in the first place is because the experts are either not sure on the placement of it, or are researching this species further. In the latter case, more specimens of the same species are often required for a proper diagnosis. Also, poor preservation of the specimen(s) in question will usually result in a more generic identification. Hopefully this specimen will be identified in the future though, an incident which I will eagerly look forward to. 

 

On this specimen particularly, the venation and color pattern of the wings of Mecopterans is vital for proper identification, as well as the organs. I found this excellent article on Bitticidae from China here: Liu, S., Shih, C., Ren, D. (2014) Four new species of hangingflies (Insecta, Mecoptera, Bittacidae) from the Middle Jurassic of northeastern China. Zookeys, 466. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4296484/. This paper lists 3 genera that are found in Liaoning: Megabittacus, Sibirobittacus, and Liaobittacus. Unfortunately, the lack of wing venation on this specimen would make it very difficult to even roughly assign this. 

 

Thanks for posting this! 

 

P.S. - I also enjoy the extant Mecopterans - I hope to collect and identify all the species in my area, it might take a while. 

[oilshale]

4 hours ago, Mainefossils said:

I believe that @oilshale would be able to help with this more...

Sorry, but you overestimate my abilities. I have a soft spot for insects but far too little knowledge to really help. If the preservation and especially the wing veining is not well visible I am lost and even then I make many mistakes. When I think I have identified an insect I usually write to the authors of the publication and ask if this could be true (and sometimes get embarrassing answers because I got the identification completely wrong again). 

It looks more like a Mecoptera, but I am not even 100% sure if this is a four-winged insect like a Mecoptera or a two-winged insect like a Diptera (for example a Tipulidae).

 

Edited September 29, 2021 by oilshale

[Quetzalcoatlus]

Thanks to both for your kind replies! I see that, as expected, it cannot be narrowed down from family level, as preservation is poor and there are four genera in Liaoning formations. I had the hope that only one species was present or clearly dominant in Liaoning jurassic, but looks like this is not the case. Agree with Mainefossils in that if a museum havce not identified a specimen in exhibit, it's because ID is extremely difficult, however I had good luck other times in this forum with other insects, ammonites, trilobites and a pterosaur, so I wanted to try before discard it.

Thanks a lot

[Crusty_Crab]

I also consider myself far from knowledgeable but I also have a soft spot for insects. In my mind, the easily recognizable features of the Mecoptera are a stinger like organ at the end of the abdomen in males; the four similar size and shaped wings which differentiate them from the Diptera, frequently with a pterostigma (thickened cell in the leading edge of the wing towards the tips); and elongate beak like feature called a rostrum held vertically under the head (hypognathous). Mecoptera from that locality have also been described with rostra that have elongated and narrowed to the point of becoming a proboscis. There's interesting research that these may have coevolved with gymnosperms as pollinators, much the same way current butterflies have long probosci having coevolved with angiosperms as pollinators but the Mecoptera declined during the Cretaceous as angiosperms began to displace gymnosperms (https://www.science.org/doi/full/10.1126/science.1178338). 

 

As a completely untrained amateur and looking at this specimen, there are none of these features, but it is still potentially a Mecoptera. If I had to guess, I would lean that this was in fact a Mecoptera because even though a rostrum or proboscis is not present, the head with the large compound eyes and hypognathous features are consistent with Mecoptera or Diptera. There looks like the faint outline of wings and the extra lobe in the bottom wing implies a separate wing, thereby making 4 wings:

 

 

Table 19.1 of Ren et al. (2010) lists about 64 species of Mecoptera in 13 families. However, this appears to still be in flux as new research is ongoing. Coincidentally, I was perusing the latest issues of the Journal of Paleontology before your post and there is a paper published in March of this year: https://www.cambridge.org/core/journals/journal-of-paleontology/article/revision-of-the-longproboscid-scorpionflies-lichnomesopsyche-ren-labandeira-and-shih-2010/9B66B82BC01BF4B3FD80AB5052A95FE4 

 

 

 

 

Bittacus is not listed in the table, but there are several species in the family Bittacidae. I would think the lack of preserved wing detail would make it difficult to determine family or genus, much less the uncertainties that this is even a Mecopteran but I could be wrong. 

 

Edited September 29, 2021 by Crusty_Crab

[Quetzalcoatlus]

Many thanks Crusty_Crab for a so complete reply :-)

Actually, at least within extant mecopterans, only Panorpidae have "a stinger like organ at the end of the abdomen in males", the remaining living families have not and I suppose most of the fossil families also doesn't. Anyway the abdomen is not preserved in this fossil, being only a blurry thing. The mecopterans that I know also lack a pterostigma, tough some bittacid species have a false pterostigma consisting in just a darkening of a preapical group of cells. The rostrum is what is consistent and defines the mecopterans. Sadly, imperfect preservation in this fossil doesn't allow to see if the insect had a rostrum. By other hand, in a fossil the presence of a rostrum could be easily misinterpreted if the preservation is not exquisite. You can mistook for example the prognathous mouthparts of a cranefly with a rostrum (see image at the end of the message).

 

The supposed indentation or lobe indicating a possible hindwing is also too much conjetural for being sure.  Antennae segments and tibial spurs would have been much more useful for identification but sadly they're not enough well preserved.,

 

The position of the wings may be a bit indicative of being a mecopteran rather than a tipulomorph. Craneflies and relatives rest with the wings either widely open or folded one over the other, and dead ones usually appear with wings elevated over the thorax. Bittacids rests with wings either widely open or folded in roof-shape. The latter position would be more consistent with the slightly-open wings seen in the fossil.