There are about 30 orders of insects (see here), usually ending with the letters “-ptera”. You should know some of these, including Lepidoptera, Coleoptera, Orthoptera, Hemiptera (“true bugs”), Diptera (FLIES!), Hymenoptera (ants, bees, and wasps), and as many of the others as your brain can hold. Rarely do we find a new one, as most of these are large, well-studied groups. But of course there are many extinct insects to be found, and the 1 million or so living species already described must be but a small fraction of all species still with us.
However, a new paper by Georger Poinar Jr. and Alex Brown in Cretaceous Research (reference below, access free), identifies a bizarre insect that doesn’t fit into any existing or extinct order, and thus has been placed in an order of its own. (See also the Oregon State University writeup, which is where first author Poinar works).
The insect, named Aesthiocarenus burmanicus, and assigned to the new order Aethiocarenodea, was found in amber excavated in Burma, and has been dated at about 99 million years ago, in the mid-Cretaceous. Here’s a picture of the thing, and what is unusual is its “triangular head with bulging eyes,” described in the paper as an isoceles triangle with the hypotenuse being the front of the head. This kind of head is absolutely unique in all known insects.
The creature is small (3-4 mm long) and wingless, but it’s a female, and we have no idea what the male looks like. But the degree of preservation in amber (remember, the bug got trapped in tree resin that then became amber) is remarkable.
The shape of the head, and narrow neck, lead the authors to speculate that this organism could move each eye through 180°, giving it really good vision. Notice the dorsoventral flattening:
Because of its shape and winglessness, the authors suggest its lifestyle:
Based on the non-specialized mouthparts, A. burmanicus gen. et sp. nov. was probably omnivorous. The narrow, flattened body suggests it could have explored bark fissures and epiphytes on tree surfaces. Wings would have been a hindrance in such a habitat. The long slender polymerous antennae were probably used to explore the surroundings and the long, slender legs indicated that it could move quickly if threatened.
This figure shows two interesting features: a weird pattern of bristles on the thorax (arrows in vertical panel to the left, A), whose function is unknown, and some kind of secretory glands at the base of head shown in lower left panel (C). These glands apparently produced an exudate (globules indicated by arrows at bottom) when the insect found itself trapped in the resin. As the paper notes:
The dorsal neck glands presumably were used for defense. Evidence that these glands were secretory is the presence of two spherical bodies with irregular borders adjacent to the paired glands (Fig. 2C). These spherical bodies are considered to represent secretions released when the fossil entered the resin.
This specimen is a female, as shown by the “gonopore” on the bottom of the abdomen (below). The authors note that it’s not clear whether a male, of which there are as yet no specimens, would have a head of the same shape, or might even have wings. (As we learned yesterday, sexual selection can sometimes cause big differences between the sexes in head shape).
Finally, is this related to any insects we know? The authors point out that the specimen has some features of one suborder of dermapterans (earwigs), but don’t share other features, so for now this order stands alone—with unknown genealogical affinities.
Poinar Jr, G. and A. E. Brown. 2016. An exotic insect Aethiocarenus burmanicus gen. et sp. nov. (Aethiocarenodea ord. nov., Aethiocarenidae fam. nov.) from mid-Cretaceous Myanmar amber. Cretaceous Research 72: 100-104