The Heteropterygidae is a family of stick insects belonging to the suborder Euphasmatodea. Species can be found in Australasia, East and Southeast Asia. More than 130 valid species have been described (at the end of 2020).
Characteristics
Size
The Heteropterygidae include both very small and very large and massive species. The representatives of the Dataminae are consistently rather small. So Planispectrum species are only long. The largest Dataminae species, with a maximum length of , are within the genera Pylaemenes and Orestes. While the subfamily Obriminae with almost in Tisamenus hebardi and up to in Trachyaretaon carmelae shows a wide range of sizes, the Heteropteryginae are considered rather large. Indeed, there are very large and massive species, such as the up to long Heteropteryx dilatata known as Malayan jungle nymph, but also small species such as those in the male sex only long Haaniella parva.
Morphology
A common autapomorphic characteristic of the Heteropterygidae is the presence of sensory areas on the prosternum. In the Dataminae is a pair of these sensory fields on the Prosternum and in the middle behind it a third on the so-called (Pro-) Furcasternit. The Obriminae lack the posterior field that is present in the Heteropteryginae. These in turn lack the front pair of sensory fields. A striking morphological feature is the females abdomen, which is widened towards the middle. In adult females this area is not only wide, but also significantly increased due to the eggs that are permanently and often produced in more or less large numbers. In the females of the subfamilies Heteropteryginae and Obriminae, the abdomen ends in a pointed secondary ovipositor that surrounds the actual ovipositor. This is ventral formed from the eighth abdominal sternite, which is here named subgenital plate, or also called operculum. Dorsally it is formed in the Heteropteryginae and the Obrimini by the eleventh abdominal tergum called the supraanal plate or Epiproct. In case of the Hoplocloniini, is formed by the tenth abdominal tergum. The smaller males have a cylindrical formed middle of abdomen, which is the thinnest area of abdomen in contrast to the females. The thickened end of the abdomen is formed ventrally by the subgenital plate and dorsally by the eighth, ninth and tenth tergum. The latter is known as the anal segment. Except in Miroceramia westwoodii and in a reduced form in Pterobrimus depressus the only representatives of their genera, the species of Obriminae and Dataminae have no wings, while the Heteropteryginae have wings. Their forewings, here developed as Tegmina and mostly also the hindwings are shortened, as in many Haaniella species and the female of Heteropteryx dilatata. In some Haaniella males and those of Heteropteryx dilatata the tegmina cover almost the entire abdomen. The fully developed hind wings underneath enable them to make short flights.
Acanthotaxy
The body can be covered with numerous pointed spines, more or less blunt thorns or tubercles, which can be found mainly on the upper side of the head and thorax. Their characteristics can be very different and often so species-specific that they are used to identify and delimit species. This method, known as acanthotaxy, was developed in 1939 by James Abram Garfield Rehn and his son John William Holman Rehn for the Obriminae, and was modified in 1998 and 2001 by Philip Edward Bragg for the Dataminae and adapted in 2016 by Frank H. Hennemann et al. for the Heteropteryginae. The respective structures are named according to their location. The spines, which are located on the vertex of the head, which is inclined downwards, act like a crown and are therefore called coronals (Corona Latin for wreath or crown). The ones above the base of the antennae are called supraantenals, those on the occiput are called supraoccipital. Spines on the pro, meso- and metanotum are referred to as pronotals, mesonatals and metanotals, respectively. Spines on the meso- and meta pleura are generally referred to as laterals and the individual spines above the coxae are referred to as supracoxals.