Rhyacophila siparantum Ibrahimi, Bilalli & Kučinić, 2021

Ibrahimi, Halil, Hlebec, Dora, Bilalli, Astrit, Musliu, Milaim, Previšić, Ana, Gashi, Agim, Grapci-Kotori, Linda, Cerjanec, Darko, Geci, Donard & Kučinić, Mladen, 2021, Rhyacophila siparantum sp. nov. (Trichoptera: Rhyacophilidae), a new species of the R. philopotamoides species group from the Republic of Kosovo with molecular and ecological notes, Ecologica Montenegrina 49, pp. 1-19 : 6-11

Rhyacophila siparantum Ibrahimi, Bilalli & Kučinić , sp. nov.

http://zoobank.org/ urn:lsid:zoobank.org:act:CECB845C-823D-4EAD-86C2-351EBBCE48E2

Type material. Holotype (1 male) ( Figure 1 ): Republic of Kosovo, Bjeshkët e Nemuna Mountains, Rugova Mountain , Pejë Municipality , spring area of the Bogë Stream , 42.763243˚N, 20.057842˚E, 1598 m asl ( Figure 2 ), 22.06.2021, leg. Halil Ibrahimi. Paratypes (8 males): same locality and collection data, except leg. Halil Ibrahimi, Astrit Bilalli, Milaim Musliu, Agim Gashi and Linda Grapci-Kotori. Paratypes (2 males): Republic of Kosovo, Bjeshkët e Nemuna Mountains, Rugova Mountain , Pejë Municipality , spring area of the Bogë Stream , 42.763243˚N, 20.057842˚E, 1598 m asl, 25.07.2018, leg. Halil Ibrahimi and Astrit Bilalli. Paratype (1 male): Republic of Kosovo, Bjeshkët e Nemuna Mountains, Rugova Mountain , Pejë Municipality , spring area of the Bogë Stream , 42.763243˚N, 20.057842˚E, 1598 m asl, 19.08.2017, leg. Halil Ibrahimi and Astrit Bilalli.

Holotype and paratypes are deposited at the Department of Biology , Faculty of Mathematics and Natural Sciences, University of Prishtina “Hasan Prishtina,” Prishtinë, Kosovo, Collection “Halil Ibrahimi- Bjeshkët e Nemuna”. One paratype is deposited at the Faculty of Science , University of Zagreb, Croatia, Collection of Trichoptera of the Faculty of Science. Another paratype is deposited at the Collection of Mladen Kučinić, Zagreb, Croatia.

Distribution. Kosovo, Bjeshkët e Nemuna.

Diagnosis. Males of the new species ( Figure 3 B ) are most similar to Rhyacophila schmidinarica ( Figure 3 A ) and Rhyacophila hirticornis ( Figure 3 C ), and differ from its most similar congeners primarily by the shape of the segment X, which is short apically and with a pronounced lateral hump on the posterior edge, in lateral view ( Figure 4 A ). In Rhyacophila schmidinarica the segment X is apically long and thin in lateral view ( Figure 4 B ). Rhyacophila hirticornis has also relatively long apical portion of segment X, without any hump on the posterior edge ( Figure 4 C ). Urbanič, Krušnik & Malicky (2000) have observed a variation in the shape of segment X in a population of R. hirticornis from Pohorje, Slovenia. In this population, segment X is slightly wider on the posterior margin, similar to R. siparantum sp. nov. However, in this population, the apex of segment X is longer than in R. siparantum sp. nov., bent downwards and also the lateral hump on the posterior margin is not specifically pronounced. This population has otherwise typically shaped second segment of inferior appendages, as in R. hirticornis .

Rhyacophila siparantum sp. nov. further differs from Rhyacophila schmidinarica and R. hirticornis by the shape of second segment of inferior appendages. Inferior appendages of R. siparantum sp. nov. by being bilobed in lateral view, generally resemble those of R. schmidinarica , but the excision between the dorsal and ventral lobes is wider and the ventral lobe is somehow smaller and bent ventrad. In R. schmidinarica the excision between the dorsal and ventral lobes is narrow, and the ventral lobe is considerably larger than the dorsal lobe. The size of lobes and excision is at a certain degree subject to the level of general curvature of inferior appendages and a slight change from strict lateral position may change the view. In R. hirticornis the second segment of inferior appendages has very shallow distal excision and is not split into two lobes. The deepest excision is noted in a population of R. hirticornis nearby Ljubljana, Slovenia ( Botosaneanu 1999), however, even in this population the second segment of inferior appendages is not split into two clear lobes, as is the case with R. siparantum sp. nov. and R. schmidinarica .

Rhyacophila siparantum sp. nov. ( Figure 5 ) further differs from its most similar congeners in the following characteristics: 1) parameres are with one row of spines subapically, extending at a certain degree on the lateral sides as well ( Figure 6 ); 2) lack of small spines on the surface of parameres, except the apex ( Figure 6 ); 3) ventral tooth on abdominal segment VII is small, while on segment VI it is very small, hardly visible ( Figure 3B ). Males of Rhyacophila schmidinarica are characterized by the following: 1) parameres with two rows of spines subapically; in some populations upper row is very close to the apex with smaller spines; 2) small spines are present on the paramere surface and apex; 3) ventral tooth on abdominal segment VII is large, and on segment VI is a medium sized ( Figure 3A ). Males of Rhyacophila hirticornis are characterized by the following: 1) parameres with one or one and half row of spines, 2) small spines are present on the paramere surface and apex; 3) size of ventral teeth on abdominal segments VII and VI as in R. schmidinarica (large and medium sized, respectively; Figure 3C ).

Description. General appearance ( Figures 4 , 5 , 6 , 7 and 8 ). Head and appendages brown. Thorax brown dorsally, and yellow brown ventrally. Legs yellowish brown, spurs brown, palpi light brown. Abdomen dark brown dorsally with irregular lines and patches and pale ventrally. Wings with a nuance of a darker brown. Forewing length 11.2 – 12.5 mm, spur formula 1-3-4. Antennae brown. There is a ventral tooth on the abdominal segments VI and VII; ventral tooth of abdominal segment VI very small, smaller than the one on segment VII, and in some specimens hardly visible.

Male genitalia. Segment IX with dorsal portion longer than the ventral one in lateral view ( Figure 5 ), dorsal margin nearly straight with a slight incision after basal third, anterior margin straight, posterior margin sinuate; in dorsal view roughly rectangular, with upper portion wider, generally wider than long. Segment X in lateral view with dorsal margin roughly concave, apex short and bulbous, posterior margin with a pronounced hump mesally; in dorsal view roughly subquadratic, widest basally, with shallow V shaped incision. First segment of each inferior appendage rectangular shaped in lateral view, dorsal margin roughly 2/3 as long as ventral margin, distal margin slightly sinuate; second segment bilobed in lateral view, upper lobe in the shape of a blunt finger, followed by a deep and wide excision in apical margin before the lower lobe. Phallic apparatus consists of aedeagus and a pair of parameres. Aedeagus with hooked tip is composed by well-developed membranous dorsal appendage and strongly developed bilobed ventral lobe. Parameres in lateral view longer than the aedeagus tip, wider basally, with one ring of spines subapically, extending laterally as well, and a few small spines apically, the rest of the parameres smooth, without spines.

Female. Unknown.

Etymology. Species epithet ‘ siparantum ’ refers to the old name of Pejë town in western Kosovo, which stands at the foothills of Rugovë, a mountain where the new species, Rhyacophila siparantum sp. nov. was found.

Ecology and distribution. Rhyacophila siparantum sp. nov. was found at a single locality in the Bogë Stream in the Rugovë Mountain, which is part of the Bjeshkët e Nemuna Mountains ( Figure 2 ), although several other streams in the area have been sampled. The substrate of the stream close to the sampling site was dominated by meso to macrolithal, surrounded by scarce vegetation. The species was collected during June, July and August, implying that it has a late spring – early summer flying period. The peak flying activity was registered during the June. The species was found in sympatry with the following species: Rhyacophila loxias Schmid, 1970 , Potamophylax cingulatus (Stephens, 1837) , Potamophylax goulandriorum Malicky, 1974 , Potamophylax pallidus (Klapalek, 1899) , Micropterna sequax McLachlan, 1875 , Limnephilus flavicornis (Fabricius, 1787) , Limnephilus sparsus Curtis, 1834 and Thremma anomalum McLachlan, 1876 .

Phylogenetic part

Mitochondrial COI sequences obtained from 4 paratype males of Rhyacophila siparantum sp. nov. were identical (one unique haplotype). The alignment of COI gene sequences was 658 bp in length. Two implemented criteria of phylogenetic reconstruction (ML and BI) resulted in congruent topologies with highly similar support values ( Figure 8 ), characterised by the presence of one deeply divergent lineage of Rhyacophila siparantum sp. nov. that has clustered with sequences of the species R. schmidinarica , and appeared as a sister subclade to species R. hirticornis . The phylogenetic analyses reveal that R. philopotamoides species group forms a monophyletic group ( Figure 9 ).

Intraspecific uncorrected p -distances range from 0.004 to 0.006 in R. hirticornis , from 0 to 0.002 in R. schmidinarica , from 0 to 0.044 in R. philopotamoides , from 0 to 0.004 in R. tristis , from 0 to 0.017 in R. nubila and from 0 to 0.042 in R. aurata ( Table 2 ).

Both applied species delimitation methods (ABGD and mPTP) resulted in the same number of delineated groups and failed in the delineation of R. siparantum sp. nov., R. hirticornis and R. schmidinarica as three tentative species and grouped them into one group. In the ABGD analysis, initial partitioning identified 3, while recursive partitioning showed the existence of 6 putative species for the majority of prior intraspecific divergence values (P). The mPTP method delimited 6 operational taxonomic units (OTUs). Other morphospecies of the genus Rhyacophila used in analyses within this study, appeared as separate OTUs.

Figures

Figure 1. Male of Rhyacophila siparantum sp. nov.

Figure 2. Picture of the type locality of Rhyacophila siparantum sp. nov.: Bogë Stream, Rugovë Mountain, Kosovo.

Figure 3. Lateral profile of: A. Rhyacophila schmidinarica (Croatia); B. Rhyacophila siparantum sp. nov. (Kosovo); C. Rhyacophila hirticornis (Croatia).

Figure 4. Lateral profile of segment X: A. Rhyacophila siparantum sp. nov. (Kosovo); B. Rhyacophila schmidinarica (Croatia); C. Rhyacophila hirticornis (Croatia).

Figure 5. Lateral profile of Rhyacophila siparantum sp. nov.

Figure 6. Dorsal profile of Rhyacophila siparantum sp. nov.

Figure 7. Enlarged aedeagus and parameres of Rhyacophila siparantum sp. nov.

Figure 8. Segment X and anal sclerites with apical band in ventrocaudal position (A); anal sclerites with apical band in dorsocaudal position (B).

Figure 9. Maximum likelihood phylogenetic tree based on the analysis of the COI sequences of Rhyacophila species. Numbers near nodes indicate maximum likelihood (ML) ultrafast bootstrap support values (BS), and Bayesian posterior probabilities (BPP). The result of morphological examination is shown by the first row of vertical bars where each color indicates a different species. The results of species delimitations are represented with the following vertical bars, from left to right, indicate the OTUs inferred by ABGD and mPTP. Terminal codes present BOLD ID, as in Table 1.