Crintella coheri ( Allen and Edmunds, 1963 )

Jacobus, Luke M. & Sites, Robert W., 2007, A new species and first stage associations in Crinitella (Ephemeroptera: Ephemerellidae: Ephemerellinae), Zootaxa 1611, pp. 45-53 : 46-48

Crintella coheri ( Allen and Edmunds, 1963)

Figs. 1–4

= C. permkami Wang and Sites, 1999 (syn. by Jacobus and McCafferty 2003b)

Descriptions. Male adult (in alcohol)—Length: body 5.2 mm; forewing 5.5 mm; hindwing 1.3 mm; axillary cord 0.1 mm; cercus and medial caudal filament subequal, 5.2 mm.

Head: General color brown. Antenna brown. Ocelli light brown; base brown, ringed with black. Compound eyes contiguous anteriorly; upper portion pink, lower portion black.

Thorax: General color brown; prothorax with anterior and posterior margins dark purple; mesothorax with axillary cords folded under mesoscutellar hind projection. Forewing hyaline with translucent milky tinge along costal margin and faint brown tinge in basal one-eighth; stigmatic area clouded with white; costa and subcosta light yellow; longitudinal veins light yellow to light brown; intercalaries and crossveins hyaline. Hindwing hyaline with purple tinge basally; all veins and intercalaries translucent white; costal projection obtuse-angulate and submedial. Foreleg light brown; length (mm) of segments: trochanter = 0.2, femur = 0.8, tibia = 1.7, tarsal segment I = 0.1, tarsal segment II = 0.6, tarsal segment III = 0.4, tarsal segment IV = 0.25, tarsal segment V = 0.2; inner claw obtuse, outer claw pointed. Mid- and hindlegs pale; midfemur light brown distally; all tarsi light brown.

Abdomen ( Figs. 3, 4 ): General color pale anteriorly and medially, light brown posteriorly, with extensive dark purple shading throughout. Abdominal terga with shading darkest laterally and posteriorly. Abdominal sterna with variable and sparse dark purple shading. Genitalia ( Fig. 2 ) light brown; forceps pale. Penes lobes rounded apically and with acute dorsal projection at base of gonopore ( Fig. 4 ); gonopore directed dorsally. Forceps segment 2 slightly expanded distally, but with margins subparallel in lateral profile ( Fig. 4 ); forceps segment 3 subovoid ( Fig. 2 ). Cercus and median caudal filament pale; segments densely covered with relatively short, hairlike setae.

Male subimago— Similar to adult, but head with frontal shelf dark purple. Abdominal shading more diffuse than adult.

Female subimago— Similar to male, but general body color pale. Head with dark maculae between lateral ocellus and compound eye. Forewing subcosta dark brown. Posterior margin of each abdominal tergum darkened.

Egg— See Jacobus and Sartori (2004: Fig. 20) and Remarks below.

Diagnoses. Male adults are identifiable by a combination of genitalia structural characters ( Figs. 2, 4 ) and abdominal coloration ( Figs. 3, 4 ). The penes lobes are apically rounded and each has an acute dorsal projection; the genital forceps have segment 2 with a relatively straight lateral profile; and segment 3 is subovoid. The abdomen has a generally light basal coloration with purple shading and has no prominent middorsal longitudinal stripe.

Larvae are distinguished from other Ephemerellinae by their highly reduced labium ( Allen and Edmunds 1963: Fig. 17) and by the structure and setation of abdominal segment 8 ( Fig. 1 ).

Variability. The alates that we examined have some basal shading on the wings, especially in the subimago stage, but it covers only a relatively small area. It is possible that the extent of shading on the wings is variable, given the variation we have observed in the coloration of forewingpads of final instars. All specimens examined had dark color basally in the developing wing, including the faded C. coheri holotype. Crinitella coheri larvae from Vietnam show variation in the extent of this basal coloration. In these specimens, the coloration ranges from covering only the extreme base of the developing forewing (as in the C. coheri types) to covering up to half of the forewing.

Distribution. Crinitella coheri has a wide Oriental distribution. It has been reported from Nepal ( Allen and Edmunds 1963), northern India, western Malaysia ( Allen 1980), and Thailand ( Wang and Sites 1999; Sites et al. 2001). We provide the first records of C. coheri from Vietnam. Bishop (1973) detailed the biology of a Malay peninsula stream inhabited by C. coheri , and Jacobus et al. (2004) reviewed some of the literature associated with the insect fauna of that stream.

Remarks. Subimagoes and adults recently were collected by Dietrich Braasch (Potsdam, Germany) in Thailand from near a stream that contained C. coheri larvae in the final instar. Braasch’s collections tentatively associated alates with C. coheri , but no reliable association could be made based on this material alone. However, two C. coheri final instars were collected from two other Thailand locations and fixed in alcohol just prior to the emergence of the subimago. We dissected the pharate subimago from each larva. These subimagoes have genitalic structure and body color that match the tentatively associated alates and, therefore, confirm the association.

A C. coheri male adult had been collected with female alates (see material examined below from a large tributary of the Sungai Selangor, Selangor, Malaysia) that Jacobus and Sartori (2004) discussed as possibly being Crinitella but which had been reported as Hyrtanella by Edmunds and Polhemus (1990). Jacobus and Sartori (2004: Fig. 20) provided a scanning electron micrograph of an egg dissected from one of these female alates, showing geometric ridges on the chorion. This morphology differs considerably from the smooth chorion of the Hyrtanella egg ( Jacobus and Sartori 2004: Fig. 19). We dissected a C. coheri female subimago from Thailand that is identical to the Malaysia series of female alates, except for having less distinct coloration on the femora. Eggs extracted from the abdomen of the Thailand female subimago correspond to eggs dissected from the Malaysia specimens ( Jacobus and Sartori 2004: Fig. 20). Based on all of this evidence, we consider the Malaysia female alates and associated eggs to be those of C. coheri .

The male adults of C. coheri are difficult to distinguish definitively from those of several species now belonging to the Ephemerellinae genera Serratella Edmunds and Torleya Lestage. Unfortunately , the current generic assignments of many Ephemerellinae species are questionable and comparisons of genera should be made with great caution. In the absence of a comprehensive global treatment of Ephemerellinae species, we note here ways to differentiate C. coheri from the type species (and therefore type concepts) of Serratella and Torleya ( Jacobus and McCafferty 2003a, Jacobus et al. 2004). Genital forceps segment two of Serratella serrata (Morgan) is somewhat twisted in lateral profile, unlike the relatively straight forceps segment two of C. coheri . The length of genital forceps segments three of Torleya major (Klapálek) is more than twice its width; genital forceps segment three of C. coheri is subovoid.

Kluge (2004) suggested a close relationship between Crinitella and Hyrtanella . Based on the subimago of Hyrtanella pascalae Jacobus and Sartori , a greater length of the terminal segment of the genital forceps will distinguish the male adults of Hyrtanella from Crinitella ( Jacobus and Sartori 2004) .

Material examined. Holotype: NEPAL, Palung, ca. 5850 ft. altitude, 17/IV/1957, E. I. Coher, larva [ PERC].

Paratypes: same data as holotype, two larvae (one set mouthparts on slide, one set mandibles in vial) [ PERC].

Other Material:

INDIA, Kashmir, 22 mi. west of Srinagar on road to Tangmarg, ca. 6500 ft. altitude, 5/IX/1968, C. Weins, one larva [ PERC]. MALAYSIA, Malay Peninsula, Selangor, Gombak R., 9 mi. north of Kuala Lumpur on Bentong Rd., 9/I–4/IX/1969, J. E. Bishop, 19 larvae, one male subimago and associated larval exuviae [ FAMU, PERC]; large trib. Sungai Selangor (24°C), 6 mi. northeast of Kota Kuba Baharu (mile 44), 1/IX/ 1978, GF& CH Edmunds, one male adult, ten female alates [ PERC]; Perak, Sungai Jor, Cameron, Highlands Rd., mile 19, 22/IX/1978, G. F. & C. H. Edmunds, one larva [ PERC]. THAILAND, Chiang Mai, Nam Chai River above hydro station intake at Fang Horticultural Station, 15/XI/1985, J. T. & D. A. Polhemus, one larva [ PERC]; Khampaeng Phet, Khlong Lan National Park, Namtok Khlong Lan, 16°07’N, 99°16’E, 20/IV/2002, five larvae [ ISUI]; same locale, but 19–20/VI/2002, BLT, one male adult [ ISUI]; Mae Hong Son, Namtok Mae Surin National Park, Nam Mae Surin, above falls, 18°56’N, 98°04’E, 12220 m altitude, 15/X/2002, GW Courtney, two larvae [ ISUI]; River Nam Lang, Soppong, 3–27/IV/2003, Braasch, four larvae, three male adults, one female subimago (dissected for eggs) [ PERC]; Phang Nga, Taimuang-Khao Lam Pi National Park, Tone Prai Waterfall, 8°26’N, 98°18’E, 63 m altitude, 12/VI/2004, Sites, Vitheepradit, Prommi, L-761, one male subimago and associated larval exuviae [ UMRM]; Phrae, Wieng Ko Sai National Park, Namtok Mae Kueng, tier 1, 17°58’N, 99°35’E, 400 m altitude, 19/XII/2002, CMU team, one male subimago and associated larval exuviae [ UMRM]; Songkhla, stream at Buddhist temple, Ton Nga Chang Wildlife Sanctuary, 6/ VII/1997, RW Sites, five larvae ( C. permkami paratypes) [ PERC]; same locale, 7/I/1995, Sites & Nichols, two larvae ( C. permkami paratypes) [ PERC]. VIETNAM, Nghê An, Khe Moi R, ca. 25km southwest of Con Cuông, Khe Moi River Forestry Camp, tropical forest edge, 18°56’N, 104°49’E, 308 m altitude, 3/VI/1995, B Hubley, ROM 956164, three larvae [ ROME]; same locale, but 7/VI/1995, one larva [ ROME]; tributary of Khe Moi R, ca. 25km southwest of Cuông, Khe Moi River Forestry Camp, near “Ophiophagus” field, tropical forest edge, 18°56’N, 104°49’E, 308 m altitude, 9/VI/1995, B Hubley, ROM 956188, one larva [ ROME].

Figures

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.