Baetis (Rhodobaetis) noa Yanai & Gattolliat

Yanai, Zohar, Gattolliat, Jean-Luc & Dorchin, Netta, 2018, Taxonomy of Baetis Leach in Israel (Ephemeroptera, Baetidae), ZooKeys 794, pp. 45-84 : 45

Baetis (Rhodobaetis) noa Yanai & Gattolliat sp. n. Figures 4D, 12, 13

" Baetis L53": Samocha 1972: 47, pl XX, figs 9-13.

Differential diagnosis.

Baetis noa is distinguishable from all known species of Rhodobaetis by the following combination of characters: seven setae on labrum, three rows of setae on paraglossae, triangular spines along tergal margins (tergum III and onward), spines on gill margins, ca. 15 triangular teeth along paraproct margin, and 6-8 triangular spines of similar size along cercotractor margin. This is the only representative of Rhodobaetis in Israel, and therefore the only one to exhibit the group characteristics, namely body covered by spatulated scales (particularly along the distal margin of the abdominal terga) and stout spines along the gill margins.

Description.

Length (mature nymphs). Female (n = 24): 4.8-8.1 mm; cerci 1.9-3.0 mm; median caudal filament 1.3-2.3 mm. Male (n = 12): 4.4-6.0 mm; cerci 2.0-2.3 mm; median caudal filament 1.3-1.7 mm.

Colouration. General colour brown (Figure 4D). Head brown with ecru spots on frons, around compound eyes and around antennal bases, labrum light brown. Antennae ecru. Turbinate eyes in male nymph amber-brown. Thorax brown with a few pale marks but with no clear pattern. Legs whitish, with light brown spot on dorsal femora, usually with proximal and distal brownish marks on femora and tibiae. Abdominal terga I–IV and VI–VIII brown with fade, pale triangular posteromedial and posterolateral spots. On terga V–IX pale spot larger, covering almost entire posterior half of tergum, with brown margins. Tergum X brown. On all terga a pair of median dark dots occasionally present. Abdominal sterna ecru to light brown. Gills milky, margins dark brown and tracheation violet. Cerci and median caudal filament ecru without bands or pattern.

Head. No carina between antennae; pedicel with elongate spatulated scales apically (Figure 12A). Dorsal surface of labrum (Figure 12B) with scattered fine, hair-like setae and seta bases, one median long seta and distolateral arc of setae composed of six long, simple setae; lateral margin with ca. ten small, fine setae; ventral surface with 2-5 small, stout setae laterodistally; distal margin with row of 30-40 fine, long, feathered setae. Hypopharynx (Figure 12D): lingua and superlingua apically covered with minute, stout setae; base of superlingua laterally serrated. Right mandible (Figure 12C) with incisors composed of seven denticles; prostheca with small denticles; space between prostheca and mola without setae or crenulation; mola apex with tuft of setae. Left mandible (Figure 12E) with incisors composed of six denticles; prostheca with four broad denticles and comb-shaped structure; space between prostheca and mola crenulate, without setae; mola apex with tuft of setae. Maxillae (Figure 12F) with four broad teeth; lacinia with row of abundant small setae ending with stouter, longer setae, second row with two serrated, stout dentisetae; base of lacinia with row of 5-6 long, stout setae; one seta perpendicular to lacinia margin; palpus 2-segmented; segment II almost as long as segment I; segment II with sparse thin setae, apical nipple carrying single short, stout scale. Labium (Figure 12G): glossa shorter than paraglossa; glossa inner margin and apex with long, fine setae; paraglossa slightly curved; apex with stout, blunt seta and distal quarter with three rows of long, simple setae; labial palpus 3-segmented; segment I as long as segments II and III combined; segment II with slightly developed distolateral protuberance, and dorsal row of five long, pointed setae; segment III apex with small, thin setae.

Thorax. Forelegs (Figure 13A): trochanters almost bare, with few short setae. Femora with dorsal row of ca. 30 mid-sized, apically rounded setae, sparser distally; one submarginal row of fewer, much shorter setae; dorsoapical setal patch composed of ca. seven stout setae and no thin setae; ventral margin with pointed, stout, short setae, distributed mostly on proximal half; surface almost bare. Tibiae with dorsal row of stout setae and few apical thin setae; ventral margin with evenly distributed row of small, pointed setae; tibiopatellar suture present. Tarsi with ca. ten pointed setae ventrally; dorsal row of ca. 20 minute setae; one pointed seta at ventral tarsus-claw meeting point. Tarsal claws (Figure 13B) hooked with one row of 9-13 acute teeth. Mid- and hindlegs similar to forelegs.

Abdomen. Terga densely covered with numerous spatulated scales, scale bases and few thin hair-like setae; distal margin of all terga with numerous spatulas, terga I to IV without spines, terga V and VI with few broad, blunt triangular spines (Figure 13C), abundant on terga VII to IX. Gill I narrow and reduced, both margins serrated (Figure 13D); gills II to VII elliptic, costal margin with robust spines, tracheation branched and clearly visible (Figure 13E). Paraproct (Figure 13F) with abundant scale bases and almost no setae, margin with 13-16 broad, triangular spines and submarginal row of spatulas; postero-lateral extension with numerous scale bases, margin with 6-14 triangular spines of similar size, submarginal row of spatulas and lateral row of small setae.

Affinities.

Baetis noa belongs to the subgenus Rhodobaetis Jacob, 2003 ( Baetis rhodani species group sensu Müller-Liebenau 1969) and exhibits the group characteristics, such as the presence of spatulas on the surface of terga, pedicel, paraproct and femora, and gills which generally bear spines along margin ( Jacob 2003, Godunko et al. 2004). The morphological attributes of the 22 Palaearctic species in the group have been reviewed by Godunko et al. (2004, 2015), Soldán et al. (2005) and Gattolliat and Sartori (2008).

The Central European species B. rhodani rhodani (Pictet, 1843) ( B. rhodani s.s.) differs from B. noa by having long setae on the dorsal margin of femora and not many tergal scales ( Gattolliat and Sartori 2008). Baetis noa also differs in the shape of the labial palpus, number of teeth on the claws and spatula density on most of its body surface. The closest relative to B. noa geographically is B. bisri Thomas & Dia, 1983, which was originally described from Lebanon. Despite the geographical proximity, some important characters distinguish the two species: B. bisri has no spines on the gill margins, 5-6 rows of setae on the paraglossae, a different tergal pattern, and a paraproct with less marginal triangular spines and scales of a different shape ( Thomas and Dia 1983). Baetis noa also has a wider labrum compared to these species. Other than B. bisri and B. rhodani , two more Rhodobaetis species were reported from Turkey: B. braaschi Zimmermann, 1980, and B. vadimi Godunko, Palatov & Martynov, 2015 ( Kazancı and Türkmen 2016; Salur et al. 2016). Baetis gemellus Eaton, 1885 and B. pseudogemellus Soldán, 1977 are excluded, as explained by Godunko et al. (2015). Unlike B. noa , no spines are present on the gill margins of B. braaschi ( Bauernfeind and Soldán 2012) and B. vadimi ( Godunko et al. 2015). Baetis milani Godunko, Prokopov & Soldán, 2004 from the Crimean Peninsula has no triangular spines on the posterior margin of terga and very abundant minute denticles on its cercotractor ( Godunko et al. 2004). The North African B. sinespinosus differs from B. noa by having more submarginal setae on the labrum, four setal rows on the paraglossa, fewer tergal scales, and considerably less marginal teeth on the paraproct ( Soldán et al. 2005). Rhodobaetis was also reported from Cyprus by Soldán and Godunko (2008), who described a new species, B. irenkae Soldán & Godunko, 2008, presumably endemic to the island. Baetis irenkae differs from B. noa by the shape of its labial palpus, shape and abundance of spatulas on the distal margin of terga, and number and shape of spines on the margin of cercotractor. The most similar species to B. noa morphologically is B. tauricus Godunko & Prokopov, 2003 which is found exclusively in the Crimean Peninsula. However, the two species differ by the number and size of the spines along the margin of the cercotractor.

Baetis noa matches the characters of the undescribed " Baetis L53" as outlined in Samocha (1972; p. 47 and plate XX therein). In his review of the Israeli mayfly fauna, this was the only species that had spines on its gill margins and a nipple on the apex of its maxillary palpus. It also matches in colour and distribution.

Etymology.

The name is a noun in apposition. The species is dedicated to Noa Truskanov, the partner, source of inspiration, and closest friend of the senior author.

Distribution and ecology.

This species is known from the tributaries of the Jordan River and from brooks and springs in the Golan Heights, where it inhabits streams of diverse sizes and current velocities (Figs 2A, E). Typical substrate in its habitats is composed mainly of pebbles and rocks of various sizes, as well as rich epilithic and submerged vegetation. Mature nymphs were collected mostly in spring ( March–May), but also in fall ( October–November).

Material examined.

Holotype. ISRAEL: 1N, Senir Stream (nature reserve), 33.2331°N, 35.6223°E, ca 130 m a.s.l., 09.iii.2017, Z. Yanai & J.-L. Gattolliat, SMNHTAU292002. Paratypes. ISRAEL: 2N, Senir Stream (Bet Hillel), 09.vi.2014, Z. Yanai; 3N (1N on slide), Senir Stream (nature reserve), 15.vii.2014, Z. Yanai; 3N, Dan Stream (Dafna), 29.vii.2015, Z. Yanai; 7N, Dan Stream (Tel Dan), 05.xi.2015, Z. Yanai & S. Cohen; 2N (on slides), Senir Stream (nature reserve), 05.xi.2015, Z. Yanai & S. Cohen; 6N, Dan Stream (Tel Dan), 31.v.2016, Y. Hershkovitz; 68N, Dan Stream (Dan), 31.v.2016, Y. Hershkovitz; 24N (1N on slide), Senir Stream (nature reserve), 09.iii.2017, Z. Yanai & J.-L. Gattolliat; 80N, Dan Stream (Tel Dan), 10.iii.2017, Z. Yanai & J.-L. Gattolliat; 2N, Dan Stream (Dan), 07.v.2017, Z. Yanai; 13N, Yehudiyya Stream, 12.iv.2018, Z. Yanai; 36N, Dan Stream (Dafna), 13.iv.2018, Z. Yanai. Other material. ISRAEL: 8N (1N on slide), Hermon Stream (Panyas Springs), 19.ii.2014, Z. Yanai; 16N (1N on slide), Maymon Spring, 22.vi.2014, Z. Yanai; 18N, Senir Stream (nature reserve), 15.vii.2014, Z. Yanai; 3N, Senir Stream (Bet Hillel), 05.xi.2015, Z. Yanai & S. Cohen; 54N, Maymon Spring, 04.iv.2016, Z. Yanai; 10N, Dan Stream (Dafna), 31.v.2016, Y. Hershkovitz.