A new synonymy in the Palearctic genus, Eremiothrips (Thys.: Thripidae)

The insect order Thysanoptera includes 6595 extant species in 789 genera worldwide. Among nine families recognized in the order, Thripidae with more than 2200 species (in 280 genera) is the second largest family in the order (Mound & Hastenpflug-Vesmanis, 2021; ThripsWiki, 2025). Eremiothrips Priesner is considered one of the genera in Thripidae within Anaphothrips genus-group (Mound & Masumoto, 2009) that live in dry areas. All species in this genus are presumably phytophagous on flowers and leaves (Minaei, 2012). Host association in Eremiothrips was discussed by Minaei (2012), who concluded that the distribution of this eremophilous genus largely depended on geography rather than any specific host plant. Thus, it seems likely that species of Eremiothrips are phytophagous and do not exhibit a specific host association. Commonly, there has been no evidence that any species in this genus adversely affects crops. However, the damage to a halophytic plant, Sarcocornia fruticosa (Amarantaceae) by a large population of immatures and adults of Eremiothrips negevi Ben-David, the species discussed in this paper, has been documented (Ben-David, 2017). The latter author claimed that the damage is similar to the typical injury to chives [Allium schoenoprasum (Amaryllidaceae)] caused by tobacco thrips, Thrips tabaci Lindeman, a cosmopolitan pest. During the second author’s research visit from Selçuk University (Türkiye) to the Senckenberg Museum in Frankfurt (Germany), conducted as part of a postdoctoral project on Eremiothrips species, she found no morphological differences between the two described species of this genus.  The aim of this paper is to propose one of these species as a synonym of the other. Moreover, an update checklist of 22 world species in company with their distributions are provided. Recent major works on the genus failed to mention polymorphism in wing’s length in the genus (Bhatti et al., 2003; Minaei, 2012; Rasool et al., 2021) so a diagnosis character for the genus is also provided.

Slide-mounted specimens (none type materials) of three females and two males of Eremiothrips manolachei (Knechtel, 1955) were examined by the second author in summer 2024 along with preparing all photographs. High-resolution micrographs were captured using a Leica FireWire DFC480 digital camera attached to a compound microscope. Detailed morphological characters were digitized under magnifications of 10× and 40× to ensure precise visualization of diagnostic structures.

Eremiothrips Priesner

Eremiothrips Priesner 1950: 28.

Diagnosis: Female macropterous, micropterous or apterous. Head broader than long; interocellar setae short. Postocular setae uniserial. Proboscis usually short, rounded at apex (mouth cone is long in Eremiothrips unicolour Rasool, Abdel-Dayem, Alattal & Aldhafer). maxillary palps 3-segmented; eyes with 6 pigmented facets, ocellar setae pair I present. Antennae usually 9-segmented ((in E. bhattii Minaei and E. efflatouni (Priesner) 8-segmented)); segment I without paired dorso-apical setae, sense cone on III and IV usually forked (simple in E. imitator Priesner). Pronotum with transverse lines of sculpture, 5–6 pairs of posteromarginal setae with one posteroangular pair usually longer and stouter (E. efflatouni and E. eshghii Minaei without long posteroangular setae). Prosternum with ferna divided. Spinula present on mesosternum, absent on metasternum. Mesothoracic sternopleural sutures present. Metafurca without basal platform. Mesonotum with or without anterior campaniform sensilla. Metanotum with median pair of setae inserted far back of anterior margin, either distinctly shorter than outer pair or sometimes longer; campaniform sensilla absent. Fore wing posterior cilia wavy; first vein with 9–12 setae, usually 3 setae on distal half; second vein with almost complete setal row. Prosternal basantra membranous. Mesosternal furcal spinula present, metasternal spinula absent. Mesothoracic sternopleural sutures present. Tarsi 2-segmented. Abdominal tergites II-VIII with setae S1 usually as long S2, tergites without ctenidia or craspeda, Posterior margin of tergum VIII with or without comb of microtrichia; sternal discal setae absent; IX with two pairs of campaniform sensilla, X with or without longitudinal split. Sternites without discal setae or craspeda; III–VII with three pairs of posteromarginal setae, II with two pairs.
Males smaller than female; with or without pore plates on sternites, tergite IX with special paired processes (drepanae) usually absent ((presnt in E. shirabudinensis (Yakhontov), E. antilope (Priesner), E. aldryhimi Rasool, Abdel-Dayem, Alattal & Aldhafer and E. unicolour)). Parameres with or without tooth (Fig. 2D).

Eremiothrips manolachei (Knechtel, 1955)

Oxythrips manolachei Knechtel, 1955: 1714

Eremiothrips negevi Ben-David, 2017: 136. Syn. n.

Material examined

FRANCE, env. de Montpellier, bord étang sale, 2♀♀, Suaeda maritima, iv.1963, Berlese, Coll. H. Priesner from Senckenberg collections. ROMANIA, Carmen Sylva (Constanta), 1♀, Aster sp., ix.1936, W. K. Knechtel, SMF T 7396, det. R. zur Strassen, 1977 from Senckenberg collections. FRANCE, Grau du Roi, 1♂, Suaeda maritima, 15.vii.1969, Coll. A. Bournier, Coll. H. Priesner from Senckenberg collections. FRANCE, env. Montpellier, Grau du Roi, 1♂, Suaeda maritima, 8.vii.1969, Coll. A. Bournier, Coll. H. Priesner from Senckenberg collections. This species described from Rumanian (Knechtel, 1955). Subsequently, the species is reported from France as well as Spain on Salicornia and Suaeda, also on Scirpus maritimus and Chenopodium rubrum (Bournier, 1971; zur Strassen, 2003). Ben-David (2017) recognized E. negevi as a new species because of the following characters: wing polymorphism (macropterous, brachypterous and apterous) (Figs 1E, 2C), nine antennal segments (Fig. 2B), narrowly transverse pore plates on sternites IV–VII of males (Fig. 2A), and the absence of drepanae (special processes on abdominal tergum IX) on tergite IX of males (Fig. 2D). All mentioned features are occurred in Eremiothrips manolachei (Figs 1, 2). Furthermore, both species share the following characteristics: body color (uniformly light brown) (Fig. 1A); sculpture on meso and metanotum; tergite VIII which bears a complete and well-developed comb of broad-based, unevenly spaced short teeth (Fig. 1B), and tergite X which has longitudinal split (Fig. 1D). Therefore, E. negevi is considered here as a new junior synonym of E. manolachei.

Eremiothrips is a member of the Anaphothrips genus-group, whose species lack long setae or bear only a single pair of prominent setae on the pronotum (Mound & Masumoto, 2009). There is much evident for phytophagy among members of this genus (Bhatti et al., 2003; 2009). However, these species are rarely collected from trees (Minaei, 2012). Moreover, no host specificity has been identified among the species, although plants growing in dry areas of the Palearctic region have the potential to serve as hosts for them (zur Strassen, 1975; Minaei, 2012, 2014; Minaei & Aleosfoor, 2020). Despite this, most reported species have been not identified as agricultural pests. However, the species discussed in this study is an exception. According to Ben-David (2017) the species acts as a pest of Sarcocornia fruticose which is commercially grown in greenhouses in southern Israel.

Fig. 1. Eremiothrips manolachei female. (A) whole body; (B) abdominal tergites VII-IX; (C) meso-metanotum; (D) abdominal tergites IX-X; (E) forewing.

Fig. 2. Eremiothrips manolachei male. (A) abdominal sternites with transverse pore plates IV–VII; (B) antenna; (C) wing; (D) tergite IX.

Similarly, most species in the genus have developed wings. One exception is E. manolachei as discussed in this paper. Recently wing polymorphism is also reported for E. similis Bhatti (Rasool et al., 2021). Considering the new synonymy presented here, Eremiothrips includes 22 species around the world (Table 1). A problem on taxonomic studies of genera such as Eremiothrips is that females of several species cannot be distinguished from each other (Bhatti et al., 2003; Minaei, 2012) so a key for discriminant of females of all species in the genus probably is not possible currently.