Parasitic wasp specimen exceptionally well preserved in amber

6 min readNov 29, 2018

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The other day I negotiated a very reasonable price for a nearly perfectly preserved six-legged, flying insect specimen in amber from a jewelry dealer in Puerto Vallarta, Mexico. Following is my best approximation of region and dating of deposition/formation of the amber and rough classification of its insect inclusion. I studied geology in post-secondary, but my knowledge of paleontology is spotty at best. If anyone can expand on my preliminary investigation into this particular specimen, it would be greatly appreciated!

Without further ado, here is the precious (Fig. 1):

Figure 2. Superficial examination of color, transparency, surface texture (micro pock marks), internal texture (wavy striations), and inclusions (micro air bubbles and detritus) all indicate the pendant’s substrate is genuine amber and not plastic, glass, or other resin.

Authenticity

Amber inclusion is one of the best, if not thee best, means of fossil preservation of small-scale flora and fauna. For centuries, amber semi-precious stones — particularly those with biological inclusions — have been prized not only for their beauty and uniqueness, but also for their scientific value. Owing to their value, they are also widely faked and forged [1].

To be absolutely sure of its authenticity, I’d have to get it spectroscopically tested [2], which would likely be more trouble than it’s worth. So for now at least, I’ll do my best with what I have at hand to verify it is a genuine fossil insect entombed in the sap of an ancient tree, rather than a modern-day species artificially embedded in glass, plastic, or other resin [1].

Posts from well respected members of thefossilforum.com [3, 4] and thenaturalamber.com [5] also provided a number of helpful tests to differentiate real amber from other materials often used as substrate in forgeries: e.g. hardness, heat capacity, melting temperature, electrostatic chargeability, buoyancy, friction, and fragrance tests.

**Figure 4.** Parasitic wasp fossil perfectly preserved in amber and crafted into silver pendant. Viewed from side.

Electrostatic chargeability and buoyancy tests could not be completed without removing the attached silver clasp. All other tests indicate the sample is genuine amber. For example: heating and scratch tests (hardness discussed in detail below) indicate the sample is not glass, plastic, or other resin; partial melting results in a distinctive ‘old tree’ smell; sample ‘feels warm to the touch’ but does not soften or emit any fragrance when vigorous friction is applied.

Additionally, the integral, transparent, wavy striations (Fig. 1, 3, 5, 6), translucency of portions of the insect’s body (Fig. 1, 2, 3, 7, 8), and pervasive microscopic bubble inclusions (Fig. 5, 6) are properties not commonly attainable in even the highest quality forgeries [1, 3].

Geology, Mineralogy

The substrate is definitely not copal or green amber, as it is not soluble in alcohol and is harder than 1–1.5 on Mohs scale of mineral hardness. Its surface cannot be scratched with a fingernail and thus has a Mohs hardness >2-2.5, but cannot be much harder, as its surface shows significant signs of scratching and wear from other, harder materials.

Thus, based on the above analysis, the substrate is very likely some form of amber. In the future I will try to view the sample under UV light to confirm the unique fluorescence of amber [6] and hopefully further narrow its depositional environment and region of origin.

There are a few primary types of amber: Baltic, Caribbean, and Dominican amber. Judging from its superficial color and transparency it appears to be either Caribbean or Dominican amber [7] — as it doesn’t have the same reddish hue typical of Baltic amber. Additionally, the acquisition location of Mexico also lends support for this conclusion. However, as any good geologist knows, going on superficial appearance (particularly color) and non-in-situ location alone for identification can often be misleading.

The sample is unlikely to be Caribbean amber, as it is not remotely aromatic, even when worn against the skin [7]. As a best approximation, according to the above mineralogical characteristics, I will assume the sample is either Dominican amber or possibly Mexican amber [7]. Further research is needed to confirm its exact origin and depositional environment [2].

Paleontology

Dominican amber dates from the Oligocene to Miocene, ~25Ma, while Mexican amber is generally agreed to being of roughly synchronous age [7].

The flying insect’s morphological structures — six legs (three segments each, with additional terminus claws), wings (dual pairs?), conjoined thorax, and ovipositor/stinger — clearly indicate it is of the order Hymenoptera; while the clearly defined ‘wasp waist’ petiole indicates it belongs to the Apocrita suborder.

As I am no paleontologist, I cannot hazard much further speculation on its taxonomic classification, other than to refer to it as a parasitic wasp. This identification is presumed based on the finely pointed structure of the ovipositor (Fig. 1, 3, 8) which negates the likelihood of it being used to saw or drill through plant or wood material in order to deposit its eggs within.

Rather, the extremely fine terminal point of its ovipositor probably indicates it was used for piercing an insect host’s body in order to deposit its larvae within the living host. However, the supposed ovipositor may also, or exclusively, have been modified into, and used as, a stinger.

There are a couple of features apparently unique to this specimen, of which I’ve been unable to find other examples of online, that may help further narrow its classification.

Firstly, the wasp has exceptionally short antennae, though without further magnification, the number of segments cannot be accurately determined. Both antennae appear to remain intact because of the fine curvature nearing their terminal ends and their approximately equal length and — though one appears to be closely wrapped around the eye structure.

Secondly, the wasp’s head segment and eyes appear rather large in comparison to the relative size of its other body segments. Owing to the surface texture and curvature of its eyes, I assume they are are exceptionally large compound eyes occupying most of its head segment. However, here I am merely guessing as my untrained eye is not able to determine the exact nature of the specimen’s eye structures. Again, any further illumination of this specimen by a professional, would be greatly appreciated!

Other examples

The most similar specimen I could find during my research and via google image searches (and reverse image searches) was a parasitic wasp in burmite amber being sold on burmiteamberfossil.com [7]. The Burmite amber specimen is very similar in size, translucency (mine is somewhat more transparent), color (mine has somewhat of a greener hue at some angles), and has rather similar internal striation patterns. Another somewhat similar specimen can be viewed here [8].

TODO: further research and referencing.

References

Parasitic wasp specimen exceptionally well preserved in amber

Authenticity

Geology, Mineralogy

Paleontology

Other examples

Written by Landon