Baetiella lanpingensis, Shi, Weifang & Tong, Xiaoli, 2015

Shi, Weifang & Tong, Xiaoli, 2015, Taxonomic notes on the genus Baetiella Uéno from China, with the descriptions of three new species (Ephemeroptera: Baetidae), Zootaxa 4012 (3), pp. 553-569 : 555-557

Baetiella lanpingensis n. sp.

( Figs. 1–14 )

Holotype. 1 mature nymph in ethanol, CHINA, Yunnan, Lanping County, Tu’e Town, near Dahua Hydropower Plant (26.34°N, 99.14°E, alt. 1,500m), 25.vii.2013, leg. Hongxing Chen.

Paratypes. 1 nymph on slides and 1 nymph in ethanol, same data as holotype.

Mature nymph. Body length 4.5–5mm, cerci slightly longer than body length, median caudal filament with one segment.

Head. Capsule brown with irregular dark brown markings on vertex and frons. Antennae approximately 1.5 times the width of head; dorsal surface of scape and pedicel with 2–3 and 5–7 scale-like setae respectively ( Fig. 1 ). Labrum rectangular ( Fig. 2 ), approximately 2.0 times wider than long; anteromedian notch deep with a small rounded lobe at the base, and each side with one medial long seta and a row of 13–15 robust and simple submarginal setae, fine and simple setae scattered laterally; ventrally bordered with feathered setae along the anterior margin. Left mandible ( Fig. 6 ): incisors fused, outer incisors slightly worn out with only 3 inner denticles, prostheca robust with 3 blunt and 3 acute denticles apically. Right mandible ( Fig. 7 ): incisors split apically, outer incisors worn out and inner incisors with 3 denticles, prostheca slender than the one on the left mandible. Hypopharynx with a median projection and superlinguae broadly truncate, covered with abundant fine setae. Maxillae ( Fig. 3 ) with three caninae and one dentiseta on crown of galealacinia, a row of 4 long basal setae and one short bristle-like hump seta on basis of galealacinia; maxillary palpus 2-segmented and subequal in length, terminal segment with a small tip at apex. Labium ( Figs 4, 5 ): glossae subequal in length to paraglossae, with a row of 8–9 stout setae along the inner margin and 2 long robust blunt setae at the apex; paraglossae approximately 2 times wider than glossae, with two rows of stout setae apically and row of 4 stout acute setae dorsally; labial palpus 3- segmented, but terminal segment almost fused with 2nd segment ( Fig. 5 ), whose length is subequal to basal segment; terminal segment broadly conical with a small tip at apex; the 2nd segment with a row of 3 acute setae along outer margin dorsally; dorsal surface with numerous pores on basal segment.

Thorax. Pronotum medium brown with distinct dark brown patterns ( Fig. 8 ), surface without tubercles or elevations; posterior margin of metanotum with a single protuberance medially. Thoracic sterna usually with a conical protuberance near inner side of each coxa. Hind wing pads minute, approximately 2.5 times longer than wide. Legs ( Fig. 14 ) paler than thorax, femora whitish shaded with brown medially and apically and a dark brown longitudinal stripe near dorsal margin; tibiae and tarsi light brown. Dorsal margin of femora with dense irregular row of long, pointed simple bristles, approximately 3/5 of femur width, as well as a pair of stout, blunt subapical setae and a regular row of scale-like submarginal setae; femoral villopore present; an irregular row of dense, fine, simple setae along dorsal side of tibia and a regular row of scale-like small submarginal setae on outer margin of tibia; tarsi with a row of sparse, fine, simple setae dorsally; tarsal claw with a row of 6–7 denticles and a pair of bowed subapical bristles. All legs lack coxal gills.

Abdomen. Abdominal terga generally bicolored, terga I–V yellowish shaded with brown marks anteromedially and the rest of terga brown; terga VI–X each with a pair of dark brown roundish sigilla (cf. Kluge & Novikova 2011) ( Figs 12, 14 ). Posterior margin of abdominal terga I–VI each with a single median protuberance, successively decreasing in length backwards ( Figs. 12, 14 ); terga surface with numerous scattered small scale bases, posterior margin with blunt denticles. Abdominal sterna generally yellowish-white, each with a pair of friction pads on anterolateral area; posterior margin on sterna V–IX each with a row of continuous long spatulate setae ( Fig. 13 ) (but interrupted medially on sternum V as in Fig. 9 ) which successively decreasing in length backwards, approximately 2–5 times longer than wide ( Figs 9, 10 ). Paraproct with numerous pores on surface and 6–7 scale-like setae along the inner margin ( Fig. 11 ). Gills on segments I–VII, oval and untracheated ( Fig. 14 ), surface scattered with numerous pores, margin slightly serrated with fine, simple setae and a few stout, pointed setae. Median caudal filament reduced to one segment, each segment of inner margin of cerci fringed with primary swimming bristles.

Imago. Unknown.

Etymology. The specific epithet is named after the type locality, Lanping, Yunnan Province, China.

Distribution. China (Yunnan).

Comments. This new species is similar to Baetiella sexta n. sp. in appearance by sharing the posteromedian margin on terga I–VI each with a single dorsal protuberance, but it can be readily distinguished from the latter by the following combination of characteristics: (1) dorsal surface of scape and pedicel scatter with scale-like setae; (2) dorsal margin of femora with close-set irregular row of long, simple bristles and a regular row of scale-like small submarginal setae; (3) 2nd segment of labial palpus without inner-apical lobe and terminal segment broadly conical; (4) posterior margin on sterna V–IX each with a row of continuous long spatulate setae; (5) median caudal filament reduced to one segment.

Figures

FIGURES 1 – 14. Baetiella lanpingensis n. sp. (1) scape and pedicel of antenna; (2) dorsal view of labrum; (3) maxilla; (4) ventral view of glossae and paraglossae; (5) ventral view of labial palpus; (6) left mandible; (7) right mandible; 8, pronotum; (9) posterior margin of sternum V; (10) posterior margin of sternum VIII; (11) paraproct; (12) metanotum and abdominal terga I – X; (13) abdominal sterna V – IX and paraprocts; (14) lateral view of abdomen.