Vol. 108, No. 2, March & April, 1997 141
CRITICAL COMMENTARY ON
THE GENUS SIPHLONISCA
(EPHEMEROPTERA:SIPHLONURIDAE)i'2
W. p. McCafferty3, George F. Edmunds, JrA
ABSTRACT: Data are presented that contravene certain unfounded statements that have been pub-
lished regarding Siphlonisca aerodromia, a siphlonurid mayfly from extreme northeastern U.S.A.
and eastern Canada. The species is shown to be locally common in restricted habitats within its
geographic range. A large number of mayfly species in North America are known from fewer locale
records and specimens. Paleontological data indicate that Siphlonisca is not represented in the
fossil record, the Holarctic family Siphlonuridae sensu stricto is not represented prior to the Ter-
tiary, and S. aerodromia should not be considered a living fossil. Cladistic data place Siphlonisca as
a sister group of the genus Parameletus. The presence of lateral abdominal flanges in the adults are
independent adaptations in a number of distantly related mayfly lineages and are related to gill
position and type in the larval stage. The presence of laterally expanded abdomens in some Paleo-
zoic insects does not necessarily denote close relationships with particular lineages of extant may-
flies. The fact that Siphlonisca is monotypic is not unique among North American mayfly genera.
In an appendix to the 1908 Report of the State Entomologist of New York,
James G. Needham described the northeastern Nearctic siphlonurid mayfly
Siphlonisca aerodromia. The description of the new genus and species was ini-
tially drafted for a single female adult from Sacandaga Park, Johnstown, New
York, collected by C. P. Alexander. However, based on additional material of
both male and female adults also collected by Alexander on June 6, 1909, and
also from Sacandaga Park, the male description was also included. The date
ascribed to this species has often been 1908 (e.g., Traver 1935; Burian and
Gibbs 1988, 1991; McCafferty 1996). The date of the species name should be
1909, as listed by Edmunds and Allen (1957) and Edmunds (1962) because the
name was not published or available until 1909 and because the description was
in part based on 1909 data. Incidentally, for the same reason, the name Pota-
manthus inequalis Needham, which appeared in the same appendix, should
also be dated 1909, as has been historically recognized in the literature. With
respect to this somewhat awkward chronology, Bae and McCafferty (1991), in
their comprehensive revision of the family Potamanthidae, referenced the name
P. inequalis under the synonymy of Anthopotamus myops as " Potamanthus
inequalis 1909 Needham In: Needham 1908. . ."
The larval stage of 5. aerodromia was originally described by Clemens (1915)
1 Received August 20, 1996; Accepted September 9, 1996.
2 Purdue Agricultural Research Program Journal No. 15146.
3 Department of Entomology, Purdue University, West Lafayette, IN 47907.
^ Department of Biology, University of Utah, Salt Lake City, UT 841 12.
ENT. NEWS 108(2): 141-147, March & April, 1997
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