Cryptotendipes casuarius (Townes)

Epler, J. H., 2018, The genus Cryptotendipes Beck et Beck in Florida, with the description of a new species (Diptera: Chironomidae: Chironominae), Zootaxa 4433 (3), pp. 583-594 : 584-585

Cryptotendipes casuarius (Townes)

Harnischia (Harnischia) casuaria Townes, 1945: 162 . Original description.

Cryptotendipes casuarius (Townes) , Saether 1977: 97, figs. 34B–D; Yan et al. 2005: 2, figs 1A–C; Zorina 2006: 343, figs. 1–2. nec Cryptotendipes casuarius (Townes) , Beck & Beck 1969: 295, figs. I-9, II-5, IV-9 (misidentification of C. emorsus ).

Townes (1945) described the species from New York and Ontario, Canada, material. Epler (1995) listed the species from Florida based on the records of Beck & Beck (1969) but noted that their C. casuarius was probably C. emorsus (Townes) . Caldwell et al. (1997) listed it from Florida and North Carolina. Epler (2001) reported it from North Carolina based on the listing from Caldwell et al. (1997) and reiterated the doubtful identity of Florida C. casuarius . The material Saether (2010) examined for his descriptions of the pupa and larva was from South Dakota and Manitoba, Canada.

Saether (1977) keyed the adults of this species and illustrated the hypopygium ( Saether 1977: figs. 34B, C, D); Yan et al. (2005) keyed the species and illustrated the male wing and genitalia (but see below); Zorina (2006) keyed the species and illustrated the male genitalia; Saether (2010) keyed, described and illustrated the pupa and larva.

The single specimen from China described as C. casuarius by Yan et al. (2006) does not appear to be C. casuarius . The gonostyli of the specimen are not sharply incised as in C. casuarius , and the dorsum of tergite IX bears what appears to be a narrow medial ridge, unlike that of C. casuarius , which has a broader, casque-like ridge. Note that the ridge in C. casuarius can be difficult to interpret in slide mounted material depending on how the specimen is mounted and how much pressure has been applied by the cover slip.

Until one has seen both C. casuarius and C. emorsus , identification of material can be confusing; both species can appear similar in a dorsal view. Lateral views can also be confusing, for T IX of C. emorsus has a distinct dorsal swelling, but that of C. casuarius is much more exaggerated (Figs. 1, 4). As noted below, both species bear microtrichia on the superior volsella, but those of C. emorsus are confined mostly to the base of the appendage (Figs. 2, 3, 5, 6, 7).

I examined the holotype, from the American Entomological Institute, now housed at Utah State University in Logan, Utah (EMUS). It consists of an uncleared male, mounted whole in Canada balsam, with a pupal exuviae, all under the same cover slip. Abdominal tergites VIII and IX are broken off the adult abdomen and are mounted laterally, with the dorsal portion of TIX broken from its base and directed posteriad. This appears to be the specimen illustrated in Fig. 186B in Townes (1945). There are some differences between my measurements of the holotype and those of Townes (1945): his AR was 2.35, mine 2.60; his wing length 1.8 mm, mine 1.50 mm; his LR1 was 1.6, mine 1.31.

The holotype pupal exuviae has counts out of the range of some of the counts given by Saether (2010). For the caudal spines of the abdominal tergites: T V—Saether 27–37, 34 (holotype 20), TVI—Saether 38–41, 40 (holotype 45), TVII—Saether 50–85, 68 (holotype 0); for anal lobe setae: Saether 26–29, 27 (holotype 21).

I have examined most of the material identified as C. casuarius in Beck & Beck (1969) and determined that it represents C. emorsus . Thus, C. casuarius is not known from Florida.

Material examined. MICHIGAN: Chippewa [Co.], St. Mary’s River, 45.9945, -83.8989, June 16, [20]13, coll. P. Hudson, 1 male [ PLH]. Wayne [Co.], Lake Erie, 804, June 6, [20]14, coll. P. Hudson, 1 male [ PLH]. Wayne [County], Lake Erie, LE Metro Park, June 5, [20]15, coll. P. Hudson, 1 male [ PLH]. NEW YORK: from Townes 1945: 160: “reared from Chautauqua Lake, N.Y., July 29, 1937, H.K. Townes”; holotype slide reads (“/” indicates line change): “ Harnischia /( Harnischia )/ casuarius /reared Tow. ‘45/Chautauqua Lake/VII. 29.37 N.Y./ Type 69”, 1 male /Pex. [ EMUS]

PLATE 1. Cryptotendipes adult structures. Fig. 1. C. casuarius (Townes) male genitalia, lateral, Michigan specimen. Fig. 2. C. casuarius male genitalia, left superior volsella, holotype. Fig. 3. C. casuarius male genitalia, right superior volsella, holotype. Fig. 4. C. emorsus (Townes) male genitalia, lateral (Florida specimen). Fig 5. C. emorsus male genitalia, left superior volsella, holotype. Fig 6. C. emorsus male genitalia, right superior volsella, holotype. Fig. 7. C. emorsus male genitalia, left superior volsella, North Carolina specimen. Fig. 8. C. rutteri Epler sp. n., male genitalia, holotype. Fig. 9. C. rutteri , male genitalia, left superior volsella, holotype. Fig. 10. C. rutteri , male genitalia, right superior volsella, holotype.