A new synonym in the subfamily Thrigmopoeinae Pocock, 1900 (Araneae, Theraphosidae)

Abstract As the species Haploclastus devamatha Prasanth & Jose, 2014 is indistinguishable from Thrigmopoeus psychedelicus Sanap & Mirza, 2014, the latter is herein considered junior synonym of the former. Occurrence of polychromatism in H. devamatha is noted, and two distinct colour morphs of the species are recognised, a pink form and a blue form. The natural history and conservation of the species are discussed and its known distribution is updated.


Introduction
The subfamily Thrigmopoeinae Pocock, 1900, a group of large, ground-dwelling, burrowing mygalomorph spiders endemic to the Western Ghats of India (Mirza and Sanap 2013), is the smallest of all the eight theraphosid subfamilies (Raven 1985) and currently comprises ten nominal species under two genera: Haploclastus Simon, 1892 (with seven species) and Thrigmopoeus Pocock, 1899 (with three species) (World Spider Catalog 2018). Though the genus Haploclastus is numerically rich, all the described species except Haploclastus tenebrosus Gravely, 1935 andHaploclastus validus (Pocock, 1899), are known only from original descriptions and most of them lack detailed descriptions and illustrations (Simon 1892, Pocock 1899, Gravely 1915, Barman 1978. Recent taxonomic treatment of Haploclastus (Siliwal and Raven 2010) indicates the possibility of uncertain placement of species within the subfamily. Similarly, Thrigmopoeus species are difficult to distinguish from Haploclastus species with morphological features. In the present paper, a proposal to synonymise Thrigmopoeus psychedelicus Sanap & Mirza, 2014with Haploclastus devamatha Prasanth & Jose, 2014 is presented. Additionally, the current distribution of H. devamatha is mapped.

Materials and methods
The specimens were studied under a Zeiss Stemi 2000-C stereomicroscope. Drawings were made by the aid of a drawing tube attached to the microscope. Field photos were taken with Canon EOS 6D camera with Canon 100mm Macro photo lens. The specimens are deposited in a reference collection housed at the Division of Arachnology, Department of Zoology, Sacred Heart College, Thevara, Cochin, Kerala, India (ADSH).   Description. For description and other details of the species, see Sanap and Mirza (2014).

Taxonomy
Justification of the synonymy. Although the types of T. psychedelicus were not examined, good illustrations and images of this species are available (Sanap and Mirza 2014: figs 1, 2a-d, 3a-e). In the original description of H. devamatha, Prasanth and Jose (2014) pointed out several diagnostic somatic features for this species. The first  fig. 2F) seem quite different from that of T. psychedelicus, detailed examination of the paratype and topotypes of H. devamatha reveals that their illustration is imperfect and misleading, and that both these specimens indeed belong to the same species. The species T. psychedelicus should thus be regarded as a junior synonym of H. devamatha.
Note. Prasanth and Jose published their findings in January 2014, whereas Sanap and Mirza published their discovery in July 2014, so priority must go to the name Haploclastus devamatha and the name Thrigmopoeus psychedelicus becomes its junior synonym.
Distribution. India (Kerala: Kollam, Pathanamthitta) (Fig. 3). Polychromatism. Females of H. devamatha are remarkable for their polychromatism (Sanap and Mirza 2014). Two distinct colour forms have been observed in the population of H. devamatha: a 'pink form' with bluish prosoma and pinkish opisthosoma and the 'blue form' with uniform bluish black prosoma and opisthosoma (Fig. 1A-B). Perhaps this change in colour is related to the age of the spider as suggested by Sanap and Mirza (2014), but confirmation requires further investigations.
Natural history and conservation. Haploclastus devamatha builds unbranched burrows lined with silk. The burrows have single entrance, which is a circular opening ornamented with dried leaves pasted together using silk to form a short turret (Fig. 1D). As noted by Sanap and Mirza (2014), the burrows are found to occur on the roadside mud embankments inside and nearby regions of the forests at a height of 1-6 metres from the ground (Fig. 1C). Rarely, adult burrows are observed on the forest floors. In the Thenmala and Kulathupuzha regions, we were able to locate a large number of juvenile and subadult burrows that are built on the roadside mud embankments. Within a stretch of 2 kilometres in the Thenmala region, 110 burrows were observed and at a stretch of 1.5 kilometres in the Kulathupuzha region, 52 burrows were found. The tendency of this species to build its burrows predominantly on the roadside mud embankments points to the fact that its survival is under threat due to the common anthropogenic activities like soil removal from the mud embankments and burning dried leaves gathered together near the mud embankments.
repository information of H. devamatha holotype. We extend our heartfelt thanks to Drs Rogerio Bertani, Brazil, Volker von Wirth, Germany and an anonymous reviewer for their constructive comments on an earlier version of the MS and to Dr Chris Hamilton, USA for his editorial efforts. We especially acknowledge the Science and Engineering Research Board (SERB)-DST, New Delhi for providing funding support under the Major Research Project No. SR/SO/AS-99/2012.