Chaetocladius parerai, Moubayed & Langton, 2019

Moubayed, Joel & Langton, Peter H, 2019, CHAETOCLADIUS BERYTHENSIS SP. N., C. CALLAUENSIS SP. N., C. GUARDIOLEI SP. N. AND C. PARERAI SP. N., FOUR RELICT SPECIES INHABITING GLACIAL SPRINGS AND STREAMS IN EASTERN PYRENEES AND LEBANON (DIPTERA: CHIRONOMIDAE) Abstract, CHIRONOMUS Journal of Chironomidae Research 32 (32), pp. 42-59 : 52-53

Chaetocladius parerai sp. n.:

dorsal part of inferior volsella ( Figs 5 C, F ) digitiform to long finger-like and distinctly projecting inwards, gonostylus ( Fig. 5E ) bearing a rounded expansion postero-apically which is hyaline and bare, differently shaped in C. guardiolei sp. n.

Geographical distribution

Chaetocladius berythensis sp. n. is known only from its type-locality in Lebanon (upper basin of the Beirut River, Western range, Mount Sannine). Chaetocladius callauensis sp. n., C. guardiolei sp. n. and C. parerai sp. n. are currently restricted to glacial springs, streams and peat bogs located in eastern Pyrenees. While C. guardiolei sp. n. is confined to the upper basin of the Tech River (1800- 2000 m), both C. callauensis sp. n. and C. parerai sp. n. occur in the upper basin of the Mantet River and Soques stream (alt. 2000-2300 m).

Ecology

The larvae of C. berythensis are rheophilic and exclusively confined to glacial karstic helocrenes with high water conductivity (Cd, up to 300 µS/ cm) and calcareous substratum. Emergence from June to early August. Associated species encountered in the same locality as the holotype include: Boreoheptagyia legeri (Goetghebuer, 1933) ; B. rotunda Serra-Tosio, 1983 ; Diamesa kasymovi Kownacki & Kownacka, 1973 ; D. sakartvella Kownacki & Kownacka, 1973 ; D. tonsa (Walker, 1856) ; Diamesa sp. A , near khumbugelida Willassen & Saether, 1987; Pseudodiamesa nivosa (Goetghebuer, 1928) ; Chaetocladius diai Moubayed-Breil, 2017 ; C. melaleucus ; C. perennis (Meigen, 1830) ; C. piger (Goetghebuer, 1913) ; Eukiefferiella fittkaui Lehmann, 1972 ; E. minor (Edwards, 1929) ; Heleniella sp. A , near ornaticollis (Edwards, 1929) ; H. sp. B, near asiatica Reiss, 1968; Metriocnemus eurynotus (Holmgren, 1838) ; M. hirticollis (Staeger, 1839) ; Thienemanniella clavicornis (Kieffer, 1911) .

Larvae of C. callauensis , C. guardiolei . and C. parerai likely occur in glacial acidic helocrenes, streams and peat bogs located in Eastern Pyrenees (altitude 2000-2300 m), where water is crystalline with siliceous substratum and a very low conductivity (Cd, 10-13µS/cm). Emergence from June to September. Associated species encountered in the same localities as for holotypes include: Diamesa aberrata Lundbeck, 1898 ; D. bertrami Edwards, 1935 ; D. bohemani Goetghebuer, 1932 ; D. cinerella Meigen, 1835 ; D. modesta Serra-Tosio, 1968 ; D. thomasi Serra-Tosio, 1970 ; D. veletensis Serra-Tosio, 1971 ; Pseudodiamesa branickii (Nowicki, 1873) ; P. nivosa (Goetghebuer, 1928) ; Syndiamesa edwardsi Pagast, 1947 ; S. hygropetrica (Kieffer, 1909) ; Bryophaenocladius subvernalis (Edwards, 1929) ; Chaetocladius guisseti Moubayed-Breil, 2017 ; C. laminatus Brundin, 1947 ; C. mantetensis Moubayed-Breil ; C. suecicus (Kieffer, 1916) ; H. ornaticollis (Edwards, 1929) ; Metriocnemus eurynotus ; Parametriocnemus valescurensis Moubayed & Langton, 1999 ; Rheocricotopus pyrenaeus Moubayed-Breil, 2018 ; R. thomasi Moubayed-Breil, 2016 ; Thienemannia gracilis Kieffer, 1909 ; T. valespira Moubayed-Breil & Ashe, 2013 ; Trissocladius orsini Moubayed-Breil & Ashe ; Micropsectra alyssae Moubayed-Breil & Ashe, 2018 ; M. ekremi Moubayed-Breil & Ashe, 2018 ; M. nohedensis (Moubayed & Langton, 1996) .

The four new Chaetocladius species appear to belong to the crenobiotic and crenophilous community of species as documented by Lindegaard (1995). Their occurrence in such preserved high mountain habitats highlights the importance of glacial springs and streams, which are considered to be microrefugia and hotspots of diversity and endemism. Like other rare members of the genus Chaetocladius occurring in high mountain glacial springs and streams (French, Italian and Swiss Alps; Eastern Pyrenees), only few individuals of C. berythensis sp. n. and C. callauensis sp. n. have been collected after extensive investigation. The melting period of snow has become much shorter over the three last decades, which has greatly affected the ecological conditions of the original habitats. Consequently, the loss of such biogeographically representative and relict species would be ecologically indicative of the global warming and climate change.

Male pupal exuviae of taxa/species and morphotypes

( Figs 6 A-L, 7A-N)

Many specimens of 10 taxa/species including associated male pharate adults and male pupal exuviae of Chaetocladius s. str. were collected between 1996 and 2013 in some glacial mountain springs, peat bogs and streams located at high altitude (2000-2300 m) in the eastern Pyrenees ( France) and High Tatra Mountains ( Slovakia). Nearly 50 associated male adults and male pupal exuviae have been examined, which allow us to provide complementary short taxonomic notes on 10 taxa/ species and morphotypes, which are briefly illustrated and described based on characters found in the male pupal exuviae. The 10 taxa/species include 6 named species ( C. melaleucus ; C. dissipatus ; C. perennis , C. guisseti , C. bitusiki , C. mantetensis ) and 4 morphotypes, 3 of which could be pupae of the above described species ( C. cf. laminatus ; C. cf. callauensis sp. n.; C. cf. guardiolei sp. n.; C. cf. parerai sp. n.).

Brief descriptions

The male pupal exuviae are described on the basis of a combination of 6 distinguishing characters, which are briefly summarized as follows:

1. Frontal setae (FS) well-developed or vestigial;

2. Shape of thoracic horn (TH);

3. Distribution pattern of dorsocentral setae with mean distance between setae: Dc 1 -Dc 2 (d1); Dc 2 - Dc 3 (d2); Dc 3 -Dc 4 (d3);

4. Shape of dorsocentrals: type-a, thick setae; typeb, thin setae; type-c, bristle-like;

5. Oval postero-median patch of spines on sternites;

6. Shape of macrosetae (M) and location of the apical lobe (ApiL) on genital sac.

Figures

Figure 5. Male adult of Chaetocladius parerai sp. n. A) anal point and tergite IX in lateral view; B) scutellum; C) hypopygium, dorsal; D) hypopygium, ventral; E) gonostylus, dorsal; F) inferior volsella.

Figure 6. Pupal exuviae of Chaetocladius spp. Frontal apotome of: A) C. cf. callauensis sp. n.; B) C. mantetensis; C) C. cf. guardiolei sp. n. Distribution pattern of dorsocentral setae on thorax of: D) C. melaleucus; E) C. perennis; F) C. guisseti; G) C. mantetensis; H) C. bitusiki; I) C. cf. laminatus; J) C. cf. callauensis sp. n.; K) C. cf. guardiolei sp. n; L) C. cf. parerai sp. n.