Obriminae Brunner

Obriminae Brunner View in CoL v. Wattenwyl, 1893

Type -genus. – Obrimus Stål, 1875b: 49 View in CoL .

Remarks. – The Obriminae was first recognized by Brunner v. Wattenwyl(1893) as Obrimi. Rehn & Rehn (1939) subdividedthe Obriminae into the two tribes, Obrimini and Datamini and Günther (1953: 551) placed these two tribes along with Heteropterygini in the subfamily Heteropteryginae . Zompro (2004) raised Heteropteryginae to family level and the tribes contained to subfamily level. This basic arrangement has since been retained with the monophyly of Heteropterygidae and its three subordinate clades supported by various studies using molecular data ( Bradler et al., 2015; Goldberg et al., 2015; Robertson et al., 2018; Büscher et al., 2018; Glaw et al., 2019; Simon et al., 2019; Bank et al., 2021) but also by an approach based on morphological data (Hennemann et al., 2016). However, the phylogenetic relationships between the three clades Dataminae , Heteropteryginae and Obriminae has been variable among the abovementioned studies, but the two studies that exclusively dealt with the Heteropteryginae (Hennemann et al., 2016; Bank et al., 2021) agree in that the small and entirely wingless Dataminae are the sister group of Heteropteryginae + Obriminae , which are characteristic for a spinose area apicalis and ♀ having a beak-like secondary ovipositor that renders an egg-deposition mode in which the eggs are buried in soil. However, even in these two studies there is noteworthy disagreement in the arrangement of the subordinate taxa of Obriminae .

The subfamily Obriminae was subdivided into three tribes by Zompro (2004: 201), the Obrimini , Eubulidini and Miroceramiini . This subdivision was rejected by Hennemann et al. (2016), who proposed a subdivision into the Miroceramiini (solely comprising the winged Wallacean genus Miroceramia ), Tisamenini (containing Tisamenus , Ilocano , Pterobrimus and Hoploclonia ) and Obrimini (containing all remaining genera of Obriminae ). While the relationships proposed on the basis of morphological characters are basically reflected by the molecular approach by Bank et al. (2021), the resulting topology within Obriminae is different and refutes all previously established tribes. In contrast to preceding arrangements this study only recognizes two tribes within Obriminae , the Hoplocloniini (only containing Hoploclonia Stål, 1875 ) and the Obrimini (comprising all other genera of Obriminae ). While Hennemann et al. (2016) interpreted the differently structured secondary ovipositor of ♀ of Hoploclonia , in which the upper portion is alternatively formed by elongation of the anal segment (= abdominal tergum X) instead of an elongated epiproct like in all other Obriminae (and Heteropteryginae ), as a reduced ancestral and newly evolved type of ovipositor, molecular data reveal Hoploclonia as sister to all remaining Obriminae and suggest the secondary ovipositor to have been evolved three times independently within the Heteropterygidae . Moreover, molecular data have revealed Pterobrimus , the only genus of Obriminae that occurs in Fiji in the Pacific Ocean, to be sister to the winged Miroceramia and Miroceramia + Pterobrimus to be sister group to all other predominantly Philippine Obrimini ( Bank et al., 2021) . The tribe Tisamenini sensu Hennemann et al. (2016) was also refuted as being polyphyletic by molecular data because Hoploclonia has resulted as sister to all remaining Obriminae and Pterobrimus was recovered as sister to Miroceramia . Surprisingly, molecular data suggest the striking Theramenes as sister to Tisamenus (and the synonymous Ilocano ). From morphological aspects however there is no support for such an assumption because both genera are well recognized by unique morphological characters that (i) readily separate them from all other Obriminae and (ii) distinguish both genera from another. No synapomorphies have so far been found that would support a sister group relationship between Theramenes and Tisamenus . Thus, and despite the high UFBoot support value (99) for this topology, the result concerning the relationship between these two genera must still be regarded as doubtful and deserves further evaluation. In general, it is noteworthy that there is little to no morphological support for Eubulides as nested within a complex that comprises Aretaon , Trachyaretaon and Sungaya and as sister to Trachyaretaon + Sungaya . The genera Aretaon , Trachyaretaon and Sungaya share several common characters, such as the conically raised vertex, presence of distinct and often composite posterior mesonotal and metanotal spines and an ovipositor in ♀ that is straight if seen in lateral aspect, whereas the head is strikingly flattened, the body armature noticeably reduced, the posterior mesonotals and metanotals are completely missing and the ovipositor of ♀ is distinctly up-curved in Eubulides . Hennemann et al. (2016) have therefore suggested close relation of Eubulides with Heterocopus , Mearnsiana and Theramenes and placed these four genera in the Theramenes -group among Obrimini .

A comprehensive study of the Philippine Obriminae was published by Rehn & Rehn (1939), which described five new genera and a new subgenus as well as 24 new species and one new subspecies. Further new taxa were described by Zompro (1996b), Hennemann & Conle, (2003, 2006), Lit & Eusebio (2005a, 2005b, 2006), Lit (2010), Acola et al. (2022) and Hennemann (2023), but these papers mostly restricted to describing new taxa. Only few papers have dealt with described taxa (e. g. Lit & Eusebio, 2008b; Seidenschwarz, 2018, Acola et al., 2022) but there is a plethora of papers that reported on various aspects of Obriminae stick insects, described previously unknown sexes or eggs and provided notes on captive breeding (e. g. Zompro, 1996a; Lit & Eusebio, 2008b; Dräger, 2012, 2013, 2014; Baker, 2015). Rehn & Rehn (1939) unfortunately described several of their new species and even one genus ( Mearnsiana ) merely from immature specimens, without knowledge of the striking differences between the development of the head and body armature between immature and mature insects of individual species. These authors lacked knowledge of the remarkable intraspecific variability that occasionally occurs, particularly in the spination of the head and body, which were the main characters that Rehn & Rehn consulted for distinguishing between the species. Almost all species were known to Rehn & Rehn by only a limited number of examples or even unique specimens, which of course hindered any conclusions that considered this important issue of the obrimoid morphology. This lack of important information has in part caused the description of several synonymic species not only by Rehn & Rehn (1939) but also by subsequent authors, nine of which are revealed herein. For the same reasons, the available keys to the species of Obriminae genera presented by Rehn & Rehn, that mostly rely on characters of the head and body spination, are only of restricted use. While the nine synonymies uncovered in the present study considerably lowers the known diversity of Obriminae , this is compensated for by the description of 18 new species in the genera Brasidas , Eubulides , Mearnsiana and Trachyaretaon .

Distribution. – Philippines, Palawan, Borneo, Talaud Islands, Wallacea, Palau Islands and Fiji.