Crinitella lacuna, Jacobus, Luke M. & Sites, Robert W., 2007

Jacobus, Luke M. & Sites, Robert W., 2007, A new species and first stage associations in Crinitella (Ephemeroptera: Ephemerellidae: Ephemerellinae), Zootaxa 1611, pp. 45-53 : 49-52

Crinitella lacuna , new species

Figs. 5–7

Descriptions. Mature larva (final instar) ( Fig. 5 )—Length: body 4.5–4.9 mm; cercus and median caudal filament subequal, each 2.2–2.6 mm. General color light brown with variable brown shading and markings; body and legs covered with long, hairlike setae.

Head: Color light brown with variable brown markings; frons pale; antennal pit, area surrounding compound eye, and area between ocelli dark brown. Antennal scape and pedicel light brown; flagellar segments golden brown, with fine, hairlike setae at apex of each segment; hairlike setae nearly one-third length of respective segment. Suboccipital spines blunt. Frons with long hairlike setae. Clypeus with scattered fine setae. Labrum brown; dorsal surface with dense transverse row of cilialike setae. Mandible external margin with scattered hairlike setae basally and pair of long cilialike setae medially. Maxilla with few distal hairlike setae; palp absent; spinous processes long and narrow, extending well beyond tip of maxilla. Labium with cilialike setae on ventral surface; palp segment 3 approximately one-half length segment 2.

Thorax: Pronotum with four dorsal protuberances. Mesonotum with transverse brown shading medially; tip of forewingpad pale to white. Legs pale; foreleg with submedial row of long spatulate setae; mid- and femora smoky brown proximally, with long spatulate setae on dorsal (posterior) margins. Claws with one or two basal denticles, two or three medial denticles, two to four long subdistal denticles on the inner margin, and subdistal setae.

Abdomen: Dorsal lamella of gill 3 extending to middle of segment 8, apically rounded, with fine distal setae, pale marginally but mostly brown; trilobed pattern indistinct. Terga 1–5 and 10 mostly pale; terga 6–9 usually brown; terga 8 and 9 sometimes pale; terga with dark longitudinal medial line and lateral shading. Terga 1–4 with hairlike setae on outer margins; tergum 5 with hairlike and spatulate setae; terga 6–9 with spatulate setae on outer margins (setae progressively shorter on segments 6–8); terga 3 and 9, and sometimes 2, with paired posterior protuberances; terga 4–8 with paired blunt spines; spines usually have zero to two spatulate setae; tergum 8 with no dorsally projecting setae. Segments 4–9 with posterolateral projections; projections 4–8 produced dorsolaterally; posterolateral projection 9 with dorsally projecting spatulate setae on inner margin. Sterna with brown sublateral maculae, with few short hairlike setae. Caudal filaments pale to white, with broad dark brown band medially; tips dark brown; whorls of spatulate setae and recurved fine hairlike setae at apex of each segment.

:

Male subimago (in alcohol)—Length 4.2–4.5 mm; forewing 4.3 mm; hindwing 1.0 mm; cercus and median caudal filament subequal, 3.2 mm.

Head: General color brown. Antenna with scape and pedicel pale; flagellar segments brown. Ocelli white; base black. Compound eyes contiguous medially; upper portion of eye pink; lower portion black.

Thorax: Prothorax brown with medial longitudinal black stripe and variable dark brown shading and black markings; mesothorax light brown with very prominent longitudinal black stripe on mesoscutellar hind projection; metathorax with very prominent medial longitudinal black stripe. Wings with slight brown shading at base; forewing with subcosta light brown. Legs pale; forefemur light brown.

Abdomen: Basal coloration pale to light brown. Anterior abdominal terga with dark lateral patches and median longitudinal streak ( Fig. 6 ); posterior terga basal coloration pale; tergum 9 with dark purple shading. Abdominal sterna pale with purple-brown lateral maculae. Genitalia (as in Fig. 2 ) pale to light brown. Penes lobes apically rounded. Forceps segment 2 with slight distal expansion; forceps segment 3 subovoid. Cercus and median caudal filament white with long hairlike setae abundant.

Female subimago— Similar to male, but with thoracic and abdominal coloration less extensive. Abdominal median longitudinal streaks apparent.

Diagnoses. Male subimagoes have genitalia like those of C. coheri . Subimagoes are distinguishable from this species, however, based on the presence of a prominent, mid-dorsal, longitudinal, dark stripe on the thorax and abdomen ( Fig. 6 ).

Larvae of C. lacuna are distinguished from C. coheri by paired, median spines on the abdominal terga, a dorsal longitudinal dark stripe, semioperculate gills 3, no maxillary palps, and by the structure and setation of abdominal segment 8 ( Fig. 7 ), which forms the posterior margin of the abdominal gill chamber. The labium is not greatly reduced.

Remarks. The male adult of C. lacuna is expected to have penes and forceps similar to those of C. coheri ( Fig. 2 ), based on our examination of the subimago of the new species.

The provisional placement of C. lacuna in Crinitella is based on the structure of male genitalia and the general similarity of alates to those of C. coheri . We acknowledge that the larvae of this new species are very similar to several species currently included in the genus Torleya (Jacobus et al. 2004) and that this similarity raises questions about the validity and species composition of the genera. Taxonomic revision of Crinitella , Torleya and Serratella (discussed under C. coheri ) will be treated after completion of global comparisons of ephemerelline species groups and associated phylogenetic analyses (Jacobus and McCafferty, in progress; Ogden et al., in progress). Until that time, we prefer to maintain taxonomic stability by allowing C. coheri and assorted Serratella and Torleya species to remain in their respective generic placements.

Etymology. The specific epithet is a Latin word that refers to a place where water collects. It is a reference to the pronounced lateral hollows on abdominal tergum 8.

Distribution. We have examined specimens from India, Thailand, and Vietnam.

Material examined. Holotype: THAILAND, Kanchanaburi, stream, Amphur Thong Pha Phum, Heuy Ka Yaeng at Ban Padsadoo Klang, 14°33’N, 98°34’E, 296 m altitude, 9/IV/2003, L-457, Sites, AV, Prommi, Setaphan, larva [ UMRM].

Paratypes: THAILAND, Chiang Mai, stream, Doi Suthep-Pui National Park, Pa Ngerb, 18°48’N, 98°56’E, 530 m altitude, 29/III/2003, UMC and CMU Teams, L-426, three larvae [ PERC, UMRM]; Doi Inthanon National Park, Mae Pan Waterfall, 18°31’N, 98°27’E, 1100 m altitude, 3/IV/2003, Sites, AV, Seetaphan, L-442, one larva [ UMRM]; Mae Hong Son, River Nam Lang, Soppong, 4/II–5/III/2004, Braasch, two larvae, two male subimagoes, two female subimagoes [ PERC]; Phrae, Wieng Ko Sai National Park, lower Nam Panjaen, gravel, 17°56’N, 99°34’E, 270 m altitude, 22/III/2003, CMU Team, three larvae [ PERC, UMRM]. VIETNAM, Thua Thien-Hue, Bach Ma National Park, ca. 13.5 km from Park entrance, stream flowing into Silvery Falls, subtropical evergreen forest, 1300 m altitude, 16°11’37”N, 107°51’19”E, 13/VI/2000, B Hubley, ROM 2000525, one larva [ ROME]; Vinh Phu·, Tam Dao Hill Station, lower waterfall of stream flowing through town, 11/V/1996, B Hubley, DC Darling, ROM 961029, one larva (parts on slide) [ ROME].

Other material (not paratypes):

INDIA, Madras, Kunjankhuzi, 400 ft. altitude, 2/I/1962, Fernand Schmid, one male subimago [ PERC]; Komadi, 950 ft. altitude, 18/I/1962, one female subimago [ PERC]. THAILAND, Lampang, Chae Son National Park, Namtok Chae Son, rock surfaces, 650 m altitude, 18°50’N, 99°28’E, 22/X/2002, CMU Team, two larvae [ ISUI]; Mae Hong Son, Namtok Maw Pang, gravel, 19°22’N, 98°22’E, 850 m altitude, 14/X/ 2002, GW Courtney, one larva [ ISUI]; Phrae, Wieng Ko Sai National Park, Namtok Maekueng, tier 1, 17°58’N, 99°35’E, 400 m altitude, 23/III/2003, CMU Team, one larva [ UMRM]. VIETNAM, Lam Dong, Da Nhim R., Duc Trong, 27/X/1984, one larva [ PERC].

: FIGURE 9. Hyrtanella christineae . Larva, abdominal tergum 8 gill cavity, dorsal view.

Figures

FIGURE 5 – 7. Crinitella lacuna, n. sp. 5. Larval habitus, dorsal view; specimen from Vinh Phu ·, Vietnam; 6. Male subimago, abdomen, dorsal view; 7. Larva, abdominal tergum 8 gill cavity, dorsal view.

FIGURE 1 – 4. Crinitella coheri. 1. Larva, abdominal tergum 8 gill cavity, dorsal view; 2. Male adult, genitalia, ventral view; 3. Male adult, abdomen, dorsal view; 4. Male adult, abdomen, lateral view.