Thalerosphyrus lamuriensis Sartori, 2014

Sartori, Michel, 2014, The species of Thalerosphyrus Eaton, 1881 (Insecta, Ephemeroptera, Heptageniidae, Ecdyonurinae) in Java and Sumatra, with some comments on the diversity of the genus in the Oriental Realm, ZooKeys 420, pp. 19-39 : 29-32

Taxon classification Animalia Ephemeroptera Heptageniidae

Thalerosphyrus lamuriensis Sartori, 2014

Ecdyonurus sumatranus Ulmer, 1939, (nymph, not female adult)

Thalerosphyrus determinatus Ulmer, 1939, (nymph, pro parte)

Thalerosphyrus sumatranus Braasch & Soldan, 1984 (nymph)

Material examined.

Besides the type material mentioned in Sartori (2014d), the following specimens have been examined.

1 nymph, Sumatra, Singkarak, stream at Subanpass (F19), 1000 m, 4.III.1929, Prof. Thienemann leg [ZMH]; 3 nymph, one partially mouted on microscopic slide, Sumatra, Toba area, stream south of Balige (FT13), 8.IV.1929, Prof. Feuerborn leg [ZMH]; 2 nymphs, Sumatra, Toba area, Balige, stream at ca 1100 m (T13), 5.IV.1929, Prof. Feuerborn leg [ZMH] [All specimens sub. nom Thalerosphyrus determinatus det. Ulmer].

1 nymph, Sumatra Utara Province, swift stream 20 km East of Parlilitan (CL 2192), 1070 m, 10.XI.1985, J.T. & D.A. Polhemus leg [MZL]; 2 nymphs, Sumatra Barat, Tarusan, upstream Tarusan, 10 m, 100°29.84'E, 1°13.61'S, 24.V.2010 (SU3), J.-M. Elouard leg [MZL]; 2 nymphs, Sumatra Barat, Kotobarapak, upstream Kototbarapack, 100 m, 100°32.08'E, 1°13.78'S, 24.V.2010 (SU4), J.-M. Elouard leg [MZL]; 4 nymphs, Sumatra Barat, Lubukbargalung, Lubuk Paraku River, 50 km south Solok, 420 m, 100°32.50'E, 0°56.75'S, 25.V.2010 (SU5), J.-M. Elouard leg [MZL].

Eggs extracted from the mature female nymph mentioned above from Polhemus collected specimens.

Sequence data.

Three specimens (SU3, SU4, SU5) have been used for the study by Vuataz et al. (2013) under the name " Thalerosphyrus " in figures and " Thalerosphyrus sp." in table S1, with voucher numbers “319SuTh”, “317SuTh” and “339SuTh” respectively, with one or two mitochondrial (CO1, 16S) and two to four nuclear genes (28S, H3, wg, EF-1α) sequenced. Access numbers in GenBank are:

Description of the nymph.

Body size: up to 21 mm (full grown female nymph).

Coloration pattern: see Figs 7-8.

Head. Labrum greatly expended laterally, ca 4 times larger than long, with narrow and somewhat acute apexes (Fig. 17); dorsal surface and anterior margin covered with long and thin setae; ventral surface with a long median arch of ca. 20 strong and pointed setae ending close to the anterior margin. Crown of the galea-lacinia of the maxillae composed of ca. 20 comb-shape setae, the median ones bearing 12-14 teeth. Right mandible (Fig. 19) with 11-12 fimbriate setae below the inner incisor and 5 long simple and thin setae below the mola; left mandible (Fig. 18) with 8-9 fimbriate setae below the inner incisor and ca. 8-9 long simple and thin setae below the mola. Hypopharynx with robust lingua bearing a tuft of small setae, superlinguae densely covered with long and thin setae up to the lower part of the superlinguae (Fig. 28). Labium with glossae rhomboid, clearly concave on their inner and outer margins near apex (Fig. 22), dorsal surface with numerous stout setae and numerous thin and simple setae.

Thorax. Pronotum greatly expended laterally and posteriorly (Fig. 7). Femora with submarginal rows of pointed bristles on the inner and outer margins, only slightly increasing in numbers from the fore to the hind leg. Bristles on the upper face of hind femora with subparallel or slightly convergent margins, apex rounded or truncate (Fig. 33). Outer margin of hind tibia with a row of 12-15 pointed bristles in marginal or submarginal position (Fig. 34). Tarsal claw with 3-4 teeth.

Abdomen. Posterolateral expansions not developed on segments I–II, moderately developed on segment III and strongly increasing in size up to VIII where they may be longer than segment IX (Fig. 9). Gill I with asymmetrical elongated and rounded plate, less than two times longer than wide (Fig. 46); gill III–VI strongly asymmetrical, wider than long (Figs 47-48), gill VII oval and asymmetrical with slightly pointed apex (Fig. 49). Posterior margin of tergites with long and pointed teeth regularly alternating with two small ones, and few microdenticles (Fig. 37). Cerci whitish with 3-4 dark brown bands increasing in size towards the apex.

Description of the eggs.

Size: ca 140-150 µm × 85-90 µm; chorion regularly covered by pedunculate KCT'S, (1.0-1.5 µm), a little bit larger at poles (Fig. 14), no micro- or mesogranules present; margin of micropyle edged, as formed by fused peduncles (Fig. 15).

Discussion.

A major surprise was to find nymphs of Thalerosphyrus lamuriensis among the material identified by Ulmer (1939) as Thalerosphyrus determinatus , because he described this nymph based on a single specimen under the name Ecdyonurus sumatranus (Ulmer, 1939, see Sartori 2014d for a complete development of this case). Thalerosphyrus lamuriensis clearly differs from the two previous species by several characters, such as the posterolateral expansions of the abdomen reaching their largest size on segment VIII (compared to segment VII in Thalerosphyrus determinatus and Thalerosphyrus sinuosus ), by the setation of the hypopharynx with long setae up to the concave margin of the superlinguae, the shape of the pronotum, the shape of the bristles on the upper face of hind femora, and the ornamentation of the hind tibiae. Together with Thalerosphyrus vietnamensis Dang, 1967, Thalerosphyrus bishopi Braasch & Soldán, 1986 and Thalerosphyrus flowersi Venkataraman & Sivamarakrishnan, 1987, Thalerosphyrus lamuriensis constitutes a group called by Kluge (2004) Ecdyonuroides/g(1) and characterized by "posterolateral projections [ …] on segments VI–VIII very long and pointed, exceeding segment length". The three above mentioned species are incompletely described, but Thalerosphyrus lamuriensis differs from them apparently by the shape of the bristles on the upper face of femora, by the shape of the first gill and by the coloration of the abdomen ( Braasch and Soldán 1984).

Thalerosphyrus lamuriensis possesses anyway far more characters in common with Thalerosphyrus determinatus and Thalerosphyrus sinuosus than the observed (although quite obvious) differences, and there is no reason on this basis to propose other generic rearrangement for Ecdyonuroides/g(1).

Eggs of Thalerosphyrus lamuriensis are very peculiar with pedunculate KCT'S, which distinguish them from the two other species.

Thalerosphyrus lamuriensis is the most abundant Thalerosphyrus species in Sumatra, and seems widespread throughout the island. In several places, it has been found together with Thalerosphyrus sinuosus .