Antennal sense cone variation in Teuchothrips species of New Caledonia, with one new generic combination (Thysanoptera, Phlaeothripinae)

https://doi.org/10.11646/zootaxa.5124.2.9 http://zoobank.org/urn:lsid:zoobank.org:pub:872B6451-F70F-4EDE-A845-5718CC6E28B1 238 Accepted by A. Cavalleri: 15 Mar. 2022; published: 1 Apr. 2022 Article ZOOTAXA ISSN 1175-5326 (print edition) ISSN 1175-5334 (online edition) Zootaxa 5124 (2): 238–244 https://www.mapress.com/zt/ Copyright © 2022 Magnolia Press Licensed under Creative Commons Attribution-N.C. 4.0 International https://creativecommons.org/licenses/by-nc/4.0/ Antennal sense cone variation in Teuchothrips species of New Caledonia, with one new generic combination (Thysanoptera, Phlaeothripinae) LAURENCE A. MOUND1 & ARTURO GOLDARAZENA2 1Australian National Insect Collection CSIRO, PO Box 1700, Canberra, ACT 2601  [email protected]; https://orcid.org/0000-0002-6019-4762 2Museo Nacional de Ciencias Naturales, Laboratorio Nacional de Referencia de Nematodos y Artrópodos de intrerés agrícola y forestal, Calle Serrano 115 Duplicado, SP-28006 Madrid, Spain.  [email protected]; https://orcid.org/0000-0003-3722-8335 Abstract Four species of Teuchothrips are recognised as endemic to New Caledonia and distinct from the many species of this genus in Australia. Three of these species are shown to have a variable number of sense cones on antennal segment IV, in contrast to most recorded species in the Liothrips-lineage. One endemic species is removed from Teuchothrips and considered here as Neocecidothrips pacificus (Bianchi) comb.n. together with illustrations and diagnostic notes. A key is provided for the four Teuchothrips species known from New Caledonia. Key words: Biodiversity, thrips, systematics, Pacific region, endemics Introduction The indigenous flora of New Caledonia is considered to comprise about 3400 species, of which 80% are endemic (Guillaumin 1948; Kaledonie.com 2022). Insects of the Order Thysanoptera are essentially plant dependent, either on living or decaying plants, hence there is an expectation that a considerable proportion of these insects is likely also to be endemic. Unfortunately, there have been no serious field surveys of the thrips of this island, but the most recent checklist included 68 species in 44 genera (Bournier & Mound 2000), with eight further species subsequently recorded (Mound & Masumoto 2005; Goldarazena et al. 2021; Mound & Ng 2021; Goldarazena & Michel 2022). Of these 76 recorded species, only 19 are considered endemic, and there are likely to be more species yet to be discovered in view of the restricted distributions recorded for other micro-organisms in New Caledonia (Caesar et al. 2017). However, a very large proportion of the thrips recorded on this island involve species that are widespread around the world, whereas only about 10 species are derived from the rich Australian fauna. The purpose of this article is to consider some leaf-feeding Phlaeothripidae that are endemic to New Caledonia. These are members of genera that are known particularly from Australia, and further emphasise the problems of recognizing genera among species of the Liothrips-lineage. The genus Teuchothrips This genus is a member of the Liothrips-lineage (Mound & Marullo 1996), in which all species usually have a single sense cone on antennal segment III and three sense cones on segment IV. This condition is generally consistent among several hundred species of this lineage, whereas three of the five species currently listed in Teuchothrips from New Caledonia are here recognised as having the sense cone numbers irregular. Amongst these species one available female paratype of T. ornatus has two sense cones on segment III of one antenna (but not both), a condition that is likely to be an aberration. But segment IV of three available paratypes of T. ornatus bears two large sense cones, and a similar condition had been found on 14 males and one female of this species collected more recently VARIATION IN NEW CALEDONIA TEUCHOTHRIPS SPECIES Zootaxa 5124 (2) © 2022 Magnolia Press · 239 (LAM5607). A similar condition was also observed on one male paratype of T. kraussi and one female paratype of T. noumeaensis. A further variation noted occurred on four females identified as T. ornatus (LAM5607) and one female paratype of T. noumeaensis; These five specimens each had two large sense cones on one antenna, but two large and one smaller sense cones on the other antenna. These variations from the typical condition amongst members of the Liothrips-lineage of three sense cones on antennal segment IV will need further consideration in the future. Detailed examination of both antennae on every individual specimen is needed to recognise this intraspecific variation in sense cone number, and the fact that it is recorded for so few species in the Liothrips-lineage may be due to lack of detailed study. Similar intraspecific variation in the number of antennal sense cones is recorded of some species of Deplorothrips in the Phlaeothrips-lineage (Mound & Tree 2016), and also of Karnyothrips flavipes in the Haplothripini (Okajima 2006). Finally, one of the species listed in Teuchothrips from New Caledonia, T. pacificus, has two large sense cones on both segments III and IV, and as discussed below this species is here transferred to the genus Neocecidothrips. The species included in Teuchothrips are closely similar in structure to species of Liothrips. The only recorded differentiating character states are that Teuchothrips species tend to have antennal segment VIII short and broadly based, and on the pronotum at least one of the five pairs of major setae is not elongate. In contrast, species of Liothrips have antennal segment VIII longer and constricted basally, and all five pairs of pronotal major setae are elongate (Mound 2008). With the transfer here of one species to Neocecidothrips there are 25 species listed under Teuchothrips (ThripsWiki 2021), including four from New Caledonia. Of the remaining species, 13 are known only from Australia, including the type species (Mound 2008). One species was described from New Guinea, two from Philippines, two from Java, two from Sri Lanka, and one from India. Each of the four species from New Caledonia is considered to be distinct from all of the species of Teuchothrips known from Australia, including many undescribed species in the collections at CSIRO, Canberra. This is not surprising, in view of the apparent specificity to particular plants by members of this genus. Key to the Teuchothrips species from New Caledonia 1. Maxillary stylets widely separated, about 50% of head width apart, retracted into head no more than one third of distance to posterior margin of eyes ................................................................................2 - Maxillary stylets close together, no more than 25% of head width apart and sometimes crossing over each other, retracted to posterior margin of eyes ................................................................................3 2. Fore tibia of both sexes with small tubercle at inner apex; postocular and pronotal major setae pointed; antennal segment III yellow, IV–V bicolored; fore wing with 13–16 duplicated cilia ..........................................cleistanthi - Fore tibia of both sexes without apical tubercle; postocular and pronotal major setae weakly capitate; antennal segments III–V yellow; fore wing with 10–12 duplicated cilia .......................................................... kraussi 3. Occipital ridge of head simple and transverse (Fig. 4); head extensively reticulate; pronotal anteromarginal setae small, 0.25 as long as antennal segment III, 0.16 as long as epimeral setae ...............................................ornatus -. Occipital ridge of head with curved sculptured area medially (Fig. 3); head with transverse lines, reticulate posterolaterally; pronotal anteromarginal setae well developed, 0.5 as long as antennal segment III, 0.5 as long as epimeral setae ........... ..........................................................................................noumeaensis Teuchothrips cleistanthi (Bournier) (Fig. 1) Hoplothrips (Odontoplothrips) cleistanthi Bournier, 1975: 323. The description of this species was stated to be based on the female holotype plus 14 females and 13 males, taken from nail galls on leaves of a species of Cleistanthus [Phyllanthaceae] at Koumac, Palachidji, near the northern coast of New Caledonia. It is one of the few species of Teuchothrips in which the maxillary stylets are about onethird of the head width apart, a condition shared also with T. kraussi. Transferred to Teuchothrips by Bournier and Mound (2000), it is particularly unusual in having a small tubercle at the inner apex of each fore tibia. For the present study, one male paratype was obtained on loan from Museum National d’Histoire Naturelle, Paris (Fig. 1). MOUND & GOLDARAZENA 240 · Zootaxa 5124 (2) © 2022 Magnolia Press FIGURES 1–4. Heads of paratypes of Teuchothrips species. (1) cleistanthi; (2) kraussi; (3) ornatus; (4) noumeaensis. Teuchothrips kraussi (Bournier) (Fig. 2) Oncothrips kraussi Bournier, 1993: 363. VARIATION IN NEW CALEDONIA TEUCHOTHRIPS SPECIES Zootaxa 5124 (2) © 2022 Magnolia Press · 241 This species was described from the female holotype plus eight females and five males, taken in rolled leaves of an unidentified plant at Mont Koghi just north of Noumea, New Caledonia. Transferred to Teuchothrips by Bournier and Mound (2000), it is an unremarkable member of that genus although with antennae that are extensively yellow. For this study, one female and one male paratypes were obtained on loan from Museum National d’Histoire Naturelle, Paris. Teuchothrips noumeaensis Bournier (Fig. 3) Teuchothrips noumeaensis Bournier, 1993: 357. This species was described from the female holotype and eight further females, taken in the rolled leaves of Hibbertia tontoutensis [Dilleniaceae] at Tontouta Valley not far from Noumea, New Caledonia. In common with many species of Teuchothrips the maxillary stylets are long, but they are particularly close together medially (Fig. 3). It seems to be very similar to T. ornatus but has a curious sculptured area medially on the postoccipital ridge of the head, and the pronotal anteromarginal setae are longer with the posteroangular setae shorter. It remains known only from the type series, of which four female and one male paratypes were studied on loan from the Museum National d’Histoire Naturelle, Paris. Teuchothrips ornatus Bournier (Figs 4, 5) Teuchothrips ornatus Bournier, 1993: 359. This species was described from the female holotype plus ten females and seven males, taken in the rolled leaves of Hibbertia lucens [Dilleniaceae] at Mont Koghi just north of Noumea, New Caledonia. The maxillary stylets are exceptionally long, and commonly cross over each other medially in the head (Figs 4, 5). The vertex is extensively reticulate, the postoccipital ridge simple, and the pronotal anteromarginal setae very small with the posteroangular setae elongate. From the type series, three female and two male paratypes were studied on loan from the Museum National d’Histoire Naturelle, Paris. In addition, a series of eight females and 14 males more recently collected were studied. These were taken from the apical buds of an Hibbertia species on Mont Do, about 70km northwest of Noumea in April, 2012 (LAM 5607). Neocecidothrips pacificus (Bianchi) comb.n. (Figs 6‒12) Arrhenothrips pacificus Bianchi, 1952: 385. This species was described from three females and three males, taken in New Caledonia at Bois du Sud, July 1950, from the rolled leaves of an undetermined plant. The descriptive notes below are based on the holotype female that was studied in Canberra, on loan from the Bishop Museum, Hawaii. The genus Arrhenothrips was erected by Hood (1919) for a single species that he described from India as ramakrishnae. That species has the typical antennal sense cone formula of members of the Liothrips lineage, 1 on III, 3 on IV, but both sexes have a stout fore tarsal tooth and females have the fore femora enlarged. However, the relationships of this genus require further study, including a further four species from India and two from Africa that were subsequently included (ThripsWiki 2021). The species considered here from New Caledonia seems unrelated to ramakrishnae in having two stout sense cones on antennal segments III and IV, and antennal segment VIII elongate and narrowed to the base. Moreover, contrary to the description by Bianchi, the fore femora are not particularly enlarged, and the fore tibial inner apex is simple and does not have “a broad tubercle-like distal production” (Fig. 7). The elongate antennal segment VIII of pacificus (Fig. 8) is similar to Litotetothrips species (Mound & Tree 2021), but the maxillary stylets are deeply retracted and MOUND & GOLDARAZENA 242 · Zootaxa 5124 (2) © 2022 Magnolia Press close together (Fig. 6). The species is here referred to Neocecidothrips, because the two known species of that genus (Mound 2008) are the only members of the Teuchothrips-group that share a similar antennal sense cone formula. FIGURES 5–12. Teuchothrips and Neocecidothrips. (5) T. ornatus head (LAM5607). N. pacificus holotype 6–12: (6) head; (7) fore tibia & tarsus; (8) antenna; (9) mesonotum, metanotum & pelta. (10) head & pronotum; (11) pronotum; (12) prosternum. Descriptive notes: Antennae 8-segmented, segments III‒VI each with 2 stout sense cones, on III both sense cones 0.7 as long as width of segment; VII sharply narrowed to base but neck not as distinct as on VI; VIII slender and narrowed to base. Head posterior to postocular setae with faint narrowly transverse reticulate lines of sculpture; maxillary stylets long, retracted to posterior margin of eyes and close together medially (Figs 6, 10). Pronotum without sculpture lines medially (Fig. 11); all five pairs of major setae capitate but anteromarginals weakly capitate and VARIATION IN NEW CALEDONIA TEUCHOTHRIPS SPECIES Zootaxa 5124 (2) © 2022 Magnolia Press · 243 35 microns long; anteroangulars 60, epimerals 105; notopleural sutures complete. Basantra absent (Fig. 12); ferna transverse but not meeting medially; mesopresternum of paired lateral triangles with a weak median sclerite anterior to mesosternal margin; metathoracic sternopleural sutures present but not long. Metanotum reticulate on posterior half but very weakly sculptured on anterior half (Fig. 9). Pelta broadly triangular, with pair of CPS. Tergite IX setae S1 capitate and shorter than tube. Acknowledgements The type slides of species described by Bournier are in the Musée d’Histoire naturelle, Paris, but that museum does not permit holotypes to be studied on loan. We are grateful to Patricia Nel at that Museum for arranging the loan to A.G. in Madrid of the paratypes listed above. Also studied on loan were four slides including paratypes from the Centre de Biologie pour la Gestion des Populations, courtesy of Emmanuelle Artige and Bruno Michel. 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