New genera and species of Rohrthripidae (Thysanoptera: Tubulifera) from Burmese Cretaceous amber.

The Rohrthripidae is a family of fossil tubuliferan thrips known exclusively from the Cretaceous. Despite typical tubuliferan features, these thrips show terebrantian character states, particularly on the wings and antennae, which have been interpreted as plesiomorphic. At present, the family includes only a single genus, with seven species. In the present study, 11 new species and four new genera of these ancestral thrips are described from Burmese Cenomanian amber: Adstrictubothrips mirapterus gen. et sp. n., Gemineurothrips microcephalus gen. et sp. n., Gemineurothrips peculiaris gen. et sp. n., Paralleloalathrips bivenatus gen. et sp. n., Rohrthrips brachyvenis sp. n., Rohrthrips multihamuli sp. n., Rohrthrips pandemicus sp. n., Rohrthrips rhamphorhynchus sp. n., Rohrthrips setiger sp. n., Sesquithrips markpankowskii gen. et sp. n. and Sesquithrips rostratus gen. et sp. n. Furthermore, Alavathrips moralesi, a species from Spanish Cretaceous amber, is placed into the Rohrthripidae and its sex is reinterpreted as male. The present study, moreover, provides a tighter definition of the Rohrthripidae and a more detailed description of important character states. Finally, it is outlined why it makes taxonomic sense to distinguish Rohrthripidae from the modern Tubulifera, the Phlaeothripidae.

Description of the second instar larva of Thermothrips mohelensis Pelikán (Thysanoptera: Thripidae).

Thermothrips mohelensis Pelikán is an extremely rare thrips found in dry steppe grassland ecosystems (Pelikán 1949, 1995; Ulitzka 2019a). It has been reported from only a few locations and almost always in very low abundance: one female each has been collected in Germany (Ulitzka 2019a), Slovenia (Kucharczyk 2008) and Turkey (Tunç 1992), two females are known from Iran (Mirab-balou Chen 2013), three from Poland (Zawirska 1988; Kucharczyk 2007) and six from Western Russia (Schliephake 1977). Larger series including males and larvae are known only from Czechoslovakia (Pelikán 1949, 1995) and from Yakutia, East Siberia where-besides other specimens-the larvae discussed below have been collected (see Evdokarova Kucharczyk 2020). The fragmented and selective occurrence of this species in steppe habitats has been interpreted to represent scattered relict populations that may have remained from a more extensive distribution far back, possibly in the wide dry grasslands of the Late Pleistocene (Ulitzka 2019a). Similar to other specialist species of those barren habitats T. mohelensis is severely threatened by the general decline of these fragile ecosystems due to natural succession or anthropogenic impact (Kucharczyk 2008; Kucharczyk Kucharcyk 2008; Ulitzka 2019a). T. mohelensis is a thermophilous (zur Strassen 2003) and highly xerophilous species. This thrips was erroneously considered an hydrophilous wetland thrips (Bhatti 1998) due to a mistranslation (see Ulitzka 2019a). T. mohelensis lives and breeds monophagously in flowers of Galium (Rubiaceae), particularly G. verum but also G. mollugo (Pelikán 1949, 1995; Schliephake 1972; Tunç 1992).

Two fossil thrips from Ethiopian amber (Thysanoptera) with description of Merothrips aithiopicus sp. n. (Thysanoptera: Merothripidae).

Amber has rarely been found in Africa and only a few samples with fossil inclusions are known (Kiefert et al. 2015). The most important fossiliferous find was reported from an outcrop at the north-western Plateau of Ethiopia a decade ago, revealing diverse inclusions of arthropods, plant remains, fungi and microorganisms (Schmidt et al. 2010). Initially, this amber was classified as originating from the mid-Cretaceous. Later studies, however, have raised questions about this determination and indicated a much younger age: Cenozoic, likely Miocene (Coty et al. 2016, Perrichot et al. 2016, Perrichot et al. 2018). The contradictory-and rather controversial discussed-new dating was based on spectroscopic analyses, revised palynological data and more comprehensive palaeoentomological results showing that insect fossils mostly belong to extant families and genera. In total, Schmidt et al. (2010) reported 22 insects from eight identified orders including two specimens of Thysanoptera: "an undetermined, wingless thrips" (obviously a larva) and a female associated with Merothripidae. A more detailed analysis of these specimens is the objective of the present study; regarding the larva, only a rough classification and description is given, as fossil larvae cannot be definitely associated with adult specimens.

A new species of Chiridurothrips Okajima from Miocene amber of the Dominican Republic (Thysanoptera: Phlaeothripidae).

The thysanopteran genus Chiridurothrips Okajima is known from a single extant species, C. hisakoae Okajima, collected in Japan (ThripsWiki 2019). Occurring on dead leaves and branches of evergreen trees in the subtropical Ryukyu Islands, this species remains known from only five females (Okajima 1981, 2006; also pers. comm. 2018). Within Phlaeothripidae, Chiridurothrips is associated with the tribe Plectrothripini. Species of this sub-group feed on fungal hyphae or the break-down products of fungal attack on decaying plant material (Mound Ng 2018). They are found mainly under the bark of trees or on dead branches, and they do not seem to inhabit leaf-litter (Okajima 1981). At present, Plectrothripini comprises 60 extant species in 13 genera, with no fossils recorded. Of these species 32 are placed in the genus Plectrothrips Hood, ten in Streptothrips Priesner, and six in Chirothripoides Bagnall, whereas both Menothrips Hood and Mastigothrips Priesner each include only two species. The remaining eight species are all placed in separate monobasic genera (ThripsWiki 2019). Concerning this strongly asymmetric classification, Mound and Ng (2018) suggest that Plectrothripini might be particularly old, with the large number of monobasic genera each representing a relict lineage. An alternative possibility, however, might be an unusual instability in the genes controlling morphogenetic processes, and thus resulting in striking autapomorphies on which each one of these genera is diagnosed (Mound Ng 2018). Species associated with Plectrothripini share the following character states (Okajima 1981; Mound Tree 2017): antennae 8-segmented, segment II with the campaniform sensillum situated in the basal half, III-IV with stout sense cones, VIII slender with narrow base; head with posterior ocelli close to compound eyes; pronotum commonly with sclerotized plate eroded or reduced, prosternal basantra week or absent; legs with fore tarsal tooth large; mid and hind tibiae commonly with apical spur-like setae; macropterae with fore wings parallel-sided, usually with duplicated cilia; pelta broad at base, abdominal tergite II eroded laterally; abdominal sternites often with reticulate glandular areas. Regarding the fore wings, it seems worth mentioning that in some members of Plectrothripini the subbasal wing vein is reduced and thus the three subbasal wing setae are lacking (see Plectrothrips tenuis Okajima, Chiridurothrips [c.f. fig. 2], Chirothripoides, Lonchothrips Hood; Bhatti 1998; Okajima 1981). This short vein that is present in (almost all) other macropterous Phlaeothripidae has been interpreted as a plesiomorphic feature that resulted from the reduction of a former well-developed longitudinal first vein of ancestral Tubulifera, the Rohrthripidae (Ulitzka 2018, 2019).

Five new species of Rohrthrips (Thysanoptera: Rohrthripidae) from Burmese amber, and the evolution of Tubulifera wings.

Rohrthripidae is a family of fossil thrips in the thysanopteran suborder Tubulifera. It includes a single genus, Rohrthrips, of which two species are previously known. Despite typical tubuliferan features, these thrips also show some terebrantian character states, particularly in the wings and antennae, and these are here interpreted as plesiomorphic. Five new species of these ancestral thrips are described from Burmese Cenomanian amber: Rohrthrips breviceps sp. n., Rohrthrips jiewenae sp. n., Rohrthrips maryae sp. n., Rohrthrips patrickmuelleri sp. n. and Rohrthrips schizovenatus sp. n.. Structures on the wings support the conclusion that the wings of Tubulifera are homologous with those of Terebrantia. Syninclusions in the amber fragments provide evidence of the diet and habitats of these ancestral thrips.

Addendum to MANFRED R. ULITZKA (2019) Five new species of Rohrthrips (Thysanoptera: Rohrthripidae) from Burmese amber, and the evolution of Tubulifera wings. Zootaxa, 4585: 027-040.

Concerning the description of Rohrthrips patrickmuelleri Ulitzka (2019), it has been brought to my attention that the depositary and serial number of the holotype was not given. This information is given below in order to comply with ICZN, Article 16.4.2 (1999).

A first survey of Cretaceous thrips from Burmese amber including the establishment of a new family of Tubulifera (Insecta: Thysanoptera).

Burmite, a Cretaceous amber coming from the north of Myanmar, is known to preserve a great diversity of fossil arthropods, particularly insects. Many inclusions of different taxa in several insect orders have been well analysed, but this is the first study focussed on the Thysanoptera found in Burmite. In the sub-order Terebrantia, family Merothripidae, Myanmarothrips pankowskiorum gen. n., sp. n. is recognized in various amber samples from a total of 34 females but only one male. In the sub-order Tubulifera, Rohrthrips burmiticus sp. n. is based on a single female with a tubular tenth abdominal segment. This is an exceptionally well-preserved specimen, and details of the mouth parts indicate that the gnathal apparatus of modern Tubulifera was already developed in the Cretaceous. Due to plesiomorphic characters with respect to extant Tubulifera, the genus Rohrthrips is transferred to Rohrthripidae fam. n., and this family is clearly differentiated from extant Phlaeothripidae.

The fossil species Merothrips dietrichi (Schliephake) comb.n. redescribed and transferred from the genus Heterothrips (Thysanoptera).

Identifying and describing fossil thrips (Thysanoptera) sometimes touches the limits of feasibility. Complications handling these tiny fossils are not only caused by their size, their position or fragmentary nature, but also by the state and condition of the matrices surrounding them. Due to poor preservation in some matrices (such as lime, potash and lignite) their identification often remains uncertain (Ulitzka 2015a). Amber, however, considered as a window on times past (Gröhn et al. 2015), presents a wide range of insect inclusions in excellent condition. Nevertheless, many problems can impede our visibility through this 'window'. Fissures, opacity or clouding in the fossil resin, as well as inclusions or bubbles of air, can cover specific characteristics of an included specimen. Curvature of the amber surface results in optical distortions that can impede a reliable assessment of certain features, and the deeper an inclusion is in the amber the greater are the problems. For these reasons cutting or grinding the amber as close as possible to a specimen is essential. In the future, synchrotron X-ray microtomography may be an alternative (Henderickx et al. 2012; van de Kamp et al. 2014), but at present is too complex and expensive.

New generic synonyms in the Palaeotropical genus Urothrips (Thysanoptera: Phlaeothripinae) with one new species from Seychelles.

Urothrips kobroi sp. n. is described from Seychelles, and reasons are given for considering Biconothrips Stannard and Coxothrips Bournier as new synonyms of Urothrips Bagnall. This genus now includes nine species, distributed between Africa and Australia, and a key to these species is provided.