Research Article |
Corresponding author: Zohar Yanai ( yanai.zohar@gmail.com ) Academic editor: Lyndall Pereira-da-Conceicoa
© 2022 Zohar Yanai, Pavel Sroka, Jean-Luc Gattolliat.
This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Citation:
Yanai Z, Sroka P, Gattolliat J-L (2022) Two new species of Alainites (Ephemeroptera, Baetidae) from the Mediterranean biodiversity hotspot. ZooKeys 1118: 73-95. https://doi.org/10.3897/zookeys.1118.84643
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The mayfly genus Alainites Waltz & McCafferty, 1994 encompassed 20 species and was represented across the West Palaearctic region by six species. Based on morphological (nymphal characters) and molecular (mitochondrial COI sequences) evidence, two new species are described: A. bengunn sp. nov. from Sardinia and A. gasithi sp. nov. from Israel. Both species are confined to narrow distribution ranges, in line with most of their congeners from the region. The key nymphal traits are discussed and identified to distinguish species in the group.
COI, Israel, Italy, mayfly, microendemics, Sardinia, systematics, West Palaearctic
Baetis Leach, 1815 (Ephemeroptera: Baetidae) is one of the most diversified mayfly genera (
Nigrobaetis Novikova & Kluge, 1987 and Alainites Waltz & McCafferty, 1994 were erected for species mainly belonging to the species groups niger and muticus, respectively, sensu
When Waltz and McCafferty (in
Currently Alainites is widely distributed across the Palaearctic (represented by 13 species) as well as in the Oriental realm (7 species). In Oriental realm, Alainites is reported both from continental areas (mainly China and Malaysia) and from a few islands (Taiwan and Borneo). Ongoing studies in Thailand, Philippines, and Indonesia clearly indicate that the genus is more widely distributed in the region, but seems nowhere very common (J. Garces, C. Suttinun, pers. comm.). During the study of other Baetidae from South East Asia, it was never found eastern to Wallace Line (i.e. in New Guinea and nearby islands) (
In Western Palaearctic, Alainites muticus (Linneaus, 1758) is the most common and widely distributed species of the genus. It has been reported across Europe, from Portugal to Ukraine and from Greece to Scandinavia (
Just behind the limit of distribution of A. muticus, species with restricted distribution were described over the last three decades. Sympatry amongst West Palaearctic Alainites species has very seldomly been recorded and is probably very rare, given the restricted distribution range of most species. In the Maghreb, Alainites oukaimeden (Thomas & Sartori, 1992) occurs in the High Atlas (Morocco), whilst Alainites sadati Thomas, 1994 is found from West Algeria to North Tunisia (
In Corsica, an endemic species, Alainites albinatii (Sartori & Thomas, 1989) was described based on nymphs and imagos (
For the Levant area,
In the current paper, we describe two species of Alainites that join the six species of Alainites distributed in the circum-Mediterranean region. The Mediterranean basin is recognised as a biodiversity hotspot (
The material treated here includes nymphs, that have been collected using a hand net or picked manually from rocks and pebbles. All material is preserved in ethanol, except for a few specimens that have been mounted on microscope slides fixed in Canada Balsam, as specified in the material examined sections below. Ethanol-preserved specimens were studied under a Leica M205 stereomicroscope; microscope slides were drawn from a drawing tube mounted on an Olympus BX51 compound microscope. Material is deposited in the
Musée Cantonal de Zoologie at Lausanne, Switzerland (
DNA for species delineation was extracted using the non-destructive protocol outlined by
Molecular reconstruction was conducted on the four newly obtained sequences from Israel and three already published sequences from Sardinia (Suppl. material
In comparison to COI sequences of other available taxa in Alainites and allied genera, the two newly described species demonstrate very low intraspecific variation (up to 0.7%) and very high interspecific distances (at least 19.2%).
Alainites muticus in Buffagani et al. 2003
Alainites cf. muticus
in
Takobia cf. albinatii
in
Holotype. 1 nymph, Italy, Sardinia, Loc near Fonni, trib. of Taloro (SA27), 40°09.05'N, 9°16.37'E, alt. 810 m a.s.l., 15.v.2009, L. Vuataz, E. Cavallo & Y. Chittaro leg.,
Italy. Sardinia, Loc. Siligo village, 40°35.36'N, 8°43.55'E, alt. 240 m a.s.l., C. Belfiore leg.
The species is distinct amongst other West Palaearctic Alainites species based on the combination of (1) six pairs of abdominal gills, (2) paraproct prolongation covered with spines on its entire surface, (3) serration between prostheca and mola, and (4) low number of dorsal setae on its fore-femora (14–20) and relatively many of them on the fore-tibiae (up to 17).
Length . Female body 7.0–7.9 mm; cerci 4.5–5.5 mm; median caudal filament ca. 2/3 of cerci. Male body 6.0–6.7 mm; cerci 4.0–5.0 mm; median caudal filament ca. 2/3 of cerci.
Colouration
(Fig.
Head. Antennae (Fig.
Alainites bengunn sp. nov., nymph, characters of the head A antenna base B labrum (left side dorsal view, right side ventral view) C right mandible (ventral view) D left mandible (ventral view) E hypopharynx F maxilla G labium (left side dorsal view, right side ventral view). B–G presented to the same scale.
Thorax. Forelegs (Fig.
Abdomen. Terga (Fig.
Unknown.
The species is endemic to an island, just like Ben Gunn who was deserted and isolated on an island by his crewmates in “Treasure Island” by R.L. Stevenson (1850–1894).
Little is known about the ecology and distribution of this species. The type locality is a small stream (less than three meters wide), shallow, and with medium current velocity. The species is only known from Sardinia where it is apparently not frequent and not very abundant.
species L55 in
Holotype. Israel. 1 female nymph; Wadi Al-Qassab, Maymon Spring, 33°06.74'N, 35°39.62'E, 290 m a.s.l., 4.iv.2016, Z. Yanai leg.,
The species is distinct amongst other West Palaearctic Alainites species based on the combination of (1) six pairs of abdominal gills, (2) paraproct prolongation with spines only along the border, (3) serration between prostheca and mola, and (4) low number of dorsal setae on its fore-femora (10–20) and fore-tibiae (6–12).
Length. Female body 3.7–4.0 mm; cerci broken; median caudal filament 1.3–1.4 mm (ca. 2/3 of cerci); male body 3.7–3.9 mm; cerci broken; median caudal filament ca. 2/3 of cerci.
Colouration
(Fig.
Head. Antennae (Fig.
Alainites gasithi sp. nov., nymph, characters of the head A antenna base B labrum (left side dorsal view, right side ventral view) C right mandible (ventral view) D left mandible (ventral view) E hypopharynx F maxilla G labium (left side dorsal view, right side ventral view). B–G presented to the same scale.
Thorax. Forelegs (Fig.
Abdomen. Terga (Fig.
Unknown.
The name is a noun in apposition. The first author dedicates the species to his former mentor Prof. Avital Gasith (1943–). He is, in many aspects, the founder of freshwater ecology research in Israel. He trained the majority of the local active experts and contributed significantly to our understanding of freshwater systems and taxa, and to their conservation.
Typical habitats of A. gasithi sp. nov. include spring-fed brooks in the western slopes of the Golan Heights, with shallow running waters upon basalt bedding. Little is known about the seasonality of this species as it has been rarely collected. Mature nymphs were collected in the spring and early summer (late March to June). Interestingly, the examined specimens were collected mainly in 2014–2019, and despite continuing research and much effort in the same sites, the species was not collected in 2020–2021, an observation that may indicate inter-annual fluctuations in population sizes. However, the species is very rare even in positive sampling event, suggesting that further research is needed for estimation of meta-population structure and stability.
The two newly described species are assigned to Alainites since they share all the synapomorphic characters of the genus, especially laterally compressed body, elongated paraproct prolongations, and prostheca of the right mandible composed of two feathered bristles (
Species | Distribution | Left mandible: margin between prostheca and mola | Mandible lateral side | Fore-femur dorsal margin: number of spines | Fore-tibia dorsal margin: number of spines | Number of gill pairs | Cuticle abdominal terga and sterna | Tergite IV: spines on distal margin | Prolongation of paraproct |
---|---|---|---|---|---|---|---|---|---|
Alainites albinatii (Sartori & Thomas, 1989) | Corsica | 10 small teeth | scale bases, shagreened | 15 | 6 | 6 | slightly shagreened | long triangular, pointed | apically covered by spines |
Alainites bengunn sp. nov. | Sardinia | serrated | scale bases, slightly shagreened | 14–20 | 9–17 | 6 | shagreened | slightly lanceolate | covered by spines |
Alainites gasithi sp. nov. | Israel | serrated | no scale bases, almost not shagreened | 10–20 | ca. 6, rarely 10–12 |
6 | smooth | long triangular, pointed | spines only on border |
Alainites kars (Thomas & Kazancı, 1989) | Turkey | only minute serration close to mola | no scale bases, almost not shagreened | > 40 in two rows | 5–9 | 6 | slightly shagreened | triangular, pointed | spines on entire surface ( |
Alainites muticus (Linnaeus, 1758) | Palaearctic | 10 small teeth | rare scale bases | 14 | 8 | 7 | slightly shagreened | short triangular, broad basally | spines only on border |
Alainites navasi (Müller-Liebenau, 1974) | Iberian Peninsula | 10 small teeth | ? | 26 | 21 | 6 | smooth | short triangular | covered by spines |
Alainites oukaimeden (Thomas & Sartori, 1992) | Morocco (High Atlas) | 10 small teeth | shagreened | 20 | 8 | 6 | strongly shagreened | long, relatively narrow | covered by spines |
Alainites sadati Thomas, 1994 | Algeria, Tunisia | 10 small teeth | no scale bases, almost not shagreened | ca. 25 | 6–9 | 6 | slightly shagreened | medium triangular | covered by spines |
Alainites bengunn sp. nov. can be distinguished from A. gasithi sp. nov. based on a presence of spines on all the surface of the paraproct prolongation (spines only on margins in A. gasithi sp. nov.). Spines restricted to the prolongation margin were originally also reported for A. kars by
Phylogenetic reconstruction of Alainites species and allied taxa, based on maximum likelihood analysis of sequences of the mitochondrial COI gene. The reconstruction includes representatives of the two new Alainites species (displayed with orange background), all other sequenced Alainites species (blue), and representative species of Nigrobaetis and Takobia (grey). For full details of selected samples see Suppl. material
Alainites bengunn sp. nov. is rather similar to the Corsican A. albinatii. The main character to distinguish them is the presence of spines on the dorsal margin of foretibiae (ca. seven for A. albinatii, at least nine in A. bengunn sp. nov.), the shape of the spines of the distal margin of terga (slender and more pointed in A. albinatii) and the spines on the paraproct prolongation (the prolongation is completely covered by small spines in A. bengunn sp. nov., whilst only the apex is covered by spines in A. albinatii).
The North African species A. sadati and A. oukaimeden usually have more femoral setae and fewer tibial setae than A. bengunn sp. nov. (Table
Nigrobaetis (Takobia) katerynae from Georgia represents a species not formally assigned in Alainites, although complying with the definition of this genus used in the present study. Until a more extensive phylogenetic analysis is done, we refrain from introducing new combinations, therefore we treat N. katerynae under the name originally proposed by
Alainites gasithi sp. nov. is more distinct amongst the West Palaearctic species, mainly due to the arrangement of spines on the paraproct prolongation, i.e., only along the lateral margin. The only two other species with similar spines arrangement are easily distinguished: A. muticus has seven pairs of gills, and A. kars has no serration between prostheca and mola, plus it has many more dorsal setae on its forefemora. Moreover, at least some populations of A. kars possess spines on all the surface of the paraproct prolongation (
The ML analysis (Fig.
Both A. bengunn sp. nov. and A. gasithi sp. nov. are known from very restricted ranges and are endemic to Sardinia and to Israel, respectively. It is possible that further research will reveal A. gasithi sp. nov. populations in Jordan, Syria, or Lebanon, although no suspicious species have been reported from there to date (e.g.,
In conclusion, identification of nymphs of Alainites based solely on morphology may be remarkably confusing. However, an integrative approach, including also molecular evidence and distribution, often allows an accurate species delimitation and a reliable identification. Similar approach should be applied to solve the potential presence of cryptic species within Alainites muticus s. l. and the assignment of populations from Sicily (
We thank Marion Podolak (Museum of Zoology Lausanne) for her lab work, as well as Emilie Cavallo, Yannick Chittaro, and Laurent Vuataz for collecting material in Sardinia and Corsica. Material from Israel was collected under collecting permits 40223, 40720, 41168, 41587, 41897, and 42160 by the Israel Nature and Parks Authority. We thank Sereina Rutschmann and Laurent Vuataz for providing unpublished sequences from the FREDIE project. We also appreciate the meaningful insights and contributions made by Thomas Kaltenbach and Roman Godunko, which improved the manuscript significantly. Roman Godunko also contributed by linking the findings of this study to unpublished material collected by Tomáš Soldán, which provided richer and more accurate information about A. bengunn sp.nov. The study was funded by the Israel Taxonomy Initiative (ITI) and the Swiss Government Excellence Scholarship (FCS), both given to ZY; and by the institutional support of Institute of Entomology (Biology Centre of the Czech Academy of Sciences) RVO: 60077344 given to PS.
Table S1
Data type: docx file.
Explanation note: Taxa used for genetic distance analysis (mitochondrial COI sequences) with GenBank accession numbers or FREDIE reference codes (novel sequences are highlighted in bold font).
Table S2
Data type: docx file.
Explanation note: Kimura 2 parameter distance amongst sequences of the mitochondrial COI gene of selected Alainites, Takobia, and Nigrobaetis species.