Serratella brevicauda, Jacobus, Luke M. & Zhou, - F., 2009

Jacobus, Luke M. & Zhou, - F., 2009, Two new species of Asian Serratella Edmunds (Ephemeroptera: Ephemerellidae), Zootaxa 2268, pp. 52-58 : 53-55

Serratella brevicauda , new species

( Figs. 1–3)

Type material. HOLOTYPE: China, Yunnan Prov., Er-yuan Co., Niu-jie Village, 24-V-1996, CF Zhou, larva [ PERC]. PARATYPES: same data, 20 larvae [ PERC, NNU].

Larva (preserved in ethanol). Length: body 9.9–11.2 mm; antennae 1.6–2.0 mm; caudal filaments 2.1–2.7 mm. Body color yellow to light brown. Head: Color yellow with light brown maculae. Antennal scape and pedicel brown; flagellar segments pale, with whorl of tiny fine, hairlike setae distally on each segment. Vertex relatively smooth. Paried suboccipital bumps variously present or absent. Long setae present along margin of head capsule under compound eye. Clypeus with short setae. Labrum with transverse row of long setae. Mandible not extending beyond margin of head capsule and with sublateral setae. Maxilla ( Fig. 2 ) stout with small subdistal patch of setae, three fimbriate medial setae, and reduced palp with three segments. Labium with palp segment 3 length about one-third that of segment 2. Thorax: Nota with few long, fine, hairlike setae and without dorsal protuberances; pronotum apparently with short anterolateral projections and with row of fine, hairlike setae on anterior and posterior margins. Legs with long, hairlike setae. Forefemur with subdistal band of stout, spatulate setae; all femora with one row of spatulate setae on posterior margin and two rows of spatulate setae on anterior margin. Tibiae with one or two irregular rows of spatulate setae. Claws ( Fig. 3 ) with five to eight denticles and with subdistal setae. Abdomen: Pair of flat, broad, blunt spines present on terga 4–7 and sometimes present on terga 3 and 8. Anterior terga with long, fine, hairlike setae on posterior margins. Dorsal lamellae of gills falcate, with brown trilobed pattern; ventral lamella of gill 6 deeply cleft; gill 7 inserted near posterolateral corner. Sterna yellow to light brown, unmarked. Caudal filaments light brown; segments with long, hairlike setae laterally along inner margins and with distal whorls of stout spatulate setae and fine setae.

Subimagoes and Adults. Unknown.

Egg. Unknown.

Addition to data matrix. brevicauda ?? 1 0 0 0 0 0 0 0 0 0 0 - 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 1 0 0 0 1 0 0 0???????

Larval variability. The suboccipital bumps sometimes appear to be absent, and the anterolateral thoracic projections, if present, vary in their development. Abdominal terga 3 and 8 sometimes lack paired, submedial spines.

Diagnosis. The larva of S. brevicauda differs from other Hyrtanellini larvae by a combination of its large size and its caudal filaments being very short relative to its body length. Within the subfamily Ephemerellinae, only two other species, Torleya lutosa Kang & Yang and T. naga Jacobus & McCafferty , have caudal filaments that are so relatively short. In extreme contrast to S. brevicauda , however, these species are much smaller, lack a palp on the maxilla, have a distal pallisade of long denticles on the claw, have semi-operculate gills, and have the caudal filaments curled ( Jacobus et al., 2004). Any anterolateral projections on the prothorax of S. brevicauda are very much shorter than those of Quatica ikonomovi (Puthz) and Q. euphratica (Kazanci) .

This species will come out at couplet 23 of Jacobus and McCafferty’s (2008: 247) key to ephemerellid larvae. In parts 23 and 23’, “anterolateral projections” should be changed to prominent anterolateral projections, so that S. brevicauda will key to the genus Serratella .

Etymology. The specific epithet refers to the short cerci and median filament of the larva.

Figures

FIGURES 2, 3. Serratella brevicauda, new species. Fig. 2. Maxilla. Fig. 3. Claw.