(Diptera: Chironomidae), Descriptions of the Female and Immatures of Potthastia Iberica Tosio, and Keys to the Known Species of Potthastia
Total Page:16
File Type:pdf, Size:1020Kb
Annotated Keys to the Genera of the Tribe Diamesini (Diptera: Chironomidae), Descriptions of the Female and Immatures of Potthastia iberica Tosio, and Keys to the Known Species of Potthastia Item Type Technical Report Authors Doughman, Jan S. Publisher University of Alaska, Institute of Water Resources and Engineering Experiment Station Download date 04/10/2021 13:57:41 Link to Item http://hdl.handle.net/11122/1820 ........... ; ... :.. .; .~ ... : .: '~."~:" ~ ..•.. ; . :.: ':~:;~ ..... (Diptera: Chironomidae), Descriptions of the Female and Immatures of Potthastia iberica Tosio, and Keys to the Known Species of Potthastia Jan S. Doughman I U.S. Geological Survey ] i I I r I I! . Institute of Water Resources/Engineering Experiment Station University of Alaska-Fairbanks Fairbanks. Alaska 99775 Report IWR-107 August 1985 .·· ABSTRACT A review of available inCormation on the tribe Diamesini led to the construction oC generic keys to -most liCe stages. Serra-Tosio (1971b) first described Potthastia iberica Crom an adult male from the Spanish Pyrenees. Evaluation of specimens collected in the Nearctic, from Idaho (in 1967) and Georgia (in 1981 and 1983), indicate that this species is extant in eastern and western highland streams that appear to be typ1cal trout streams. This new group of specimens contained a mature male and female pupa and immatures, and associations made it possible to describe the female and the immatures for the first time. Adult specimens conform very closely to the hololype. The known species of Potthastia are keyed. ii TAllLE OF CONTENTS Abstract. • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • i i Introduction ••• •.• ••••• • • •• " . • •••• .•••• . • •••• • • •• •••••• •• • •• • Generic keys to the adult males, pupae and larvae of the tribe Diamesini, with /I key to the series oC Potthastia. • • • • • • • • • • • • • • 3 Males • •• . " •.•• • . •• • •• • •• • • •.•• • " • • •• ••••••• " • • • • • • • • 5 Pupae. • . • . • • • • • • . • • • • • • • • . • • . • • •. • • • • • . • • • • • • • • • • • • • •• 12 Larvae. • • • • • . • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • . • • • • . 14 Pottthastia Iberica Serra-Tosio. • • • • • • • . • • • • • • • • • • • • • • • • • • • • . • • • • • 20 Female • •••• • • .• •• • •• • • ••••. • • • ••• " • . • • . • • • •• • •• • • • • • • 21 Pupa. • • • • • • • • • • • • • • • • • • • • • • • . • • • • • • • • • • • • • • • .. • • • • •• • 21 Larva. • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • . • • • • • • • • • • • • • • • • 24 Material. • • • • • . • • • • • • • • • • • • • • . • • • • • • • • •• • • • . • • • • . • • • • •. • 26 Ecology ••• •• • •• • • • ••••• • ••••..• •• • • " • ••• • •• • " • • • • • • •• 26 Acknowledgements. • • . • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • 28 References • • • • " • • • • • • • . • • • • • • • • • • • • . • • • • • • • • • • • • • • • • • • • . • • • 29 Captions. • . • • • • • • • . • • • • • • • • . • • . • • • . • • • • • • • • • • • • • • • • • • • • • • • • • 35 Figures. • • • • • • • • • . • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • . • • • • • • • • •• 38 iii INTRODUCTION Pagast (1947) published Il compendium of prior descriptions of species milking up the tribe Piamesini. This work summarized the previous findings oC such workers as Goetghebuer,KieHer, Edwards, and Thienemann on adults and pupae. Johannsen (1937), Thienemann (1952), Roback (1957) and Pankrlltovll (1970) produced keys to the larvae of this tribe. The descriptions provided in these works are insufficient t() Cully ·differentillte the genera and species as presently conceived. More recent works by Oliver (1959), Serra-Tosio (1971a), Hansen and Cook (1976), Rossaro (1980a, b), and Kownacki (1981) include more complete descriptions or clarify some of the taxonomic problems that Pagast (1947) did not consider. Doughman (1983) has keyed and described the known .larvae a·nd summarized data on the distribution and nomenclature of four genera of the subfamily Diamesinae sensu Sa ether. The phylogeny of the tribe Diamesini has been established through the works of Pagast (1947) Brundin (1966), and Saether (1976, 1977, 1979). Serra-Tosio (1968) prepared a different phylogenetic scheme which was essentially an inversion of the prior schemata. Saewedal (1982)andWi1!assen (1982) questioned thecorreclness of Serra-Tosio's revisions. This tribe has some heterogeneous genera showing a wide variety in hypopygial structures (e.g., Diamesa and Syndiamesa). The genera Potthastia lind PagasUa were erected on relatively abnormal species as reClectedby the larval stage (Pagast, 1947, Oliver, 1959). Q. appendiculata Lundstroem does not faU neatly into any known genus. Onychodiamesa P.agast and Lappodiamesa Serra-Tosio were erected only Crom the adult. Taxonomic placement problems as those associated with Hesperodiamesa (Sublette, 1967a) could be avoided if the erection of new genera in the tribe Diamesini were delayed until other life stages are known. Therefore, it cll,n be assumed that the intrinsic relationships of the Diamesini are not yet settled. Through the framework of the key, modern descriptions of the genera in the Ildult male, pupal, and larval states are summarized from many .foreign papers in this report. In like manner, a summary of Potthastia is specifically addressed. The immatu.res of ~. iberica Serra-Tosio described herein revealed that Potthastia gaedii Meigen has n unique group of characteristics in nil stages. This paper is directed to the applied worker in water-quality stUdies. Hopefully, this translation/summary is sufficient, necessitating one to secure only the more recent treatments of these genera at the species level. 2 GENERIC KEYS TO THE ADULT MALES, PUPAE AND LARVAE OF THE TRIBE DIAMESINI, WITH A KEy TO THE SPI!CIES OF POTTHASTlA The following remarks pertain directly to the usa of the subsequent keys. Hesperodiamesll is absorbed into Pagastill (cf. Serra-Tosio, 1976); see Oliver and Roussel (1982). The species of the genera Syndiamesa (=Parapotthastia Tos.), Lnppodiamesa, Onychodiamesa, and the Diamesa dampfi-group lire as yet known only from the Pa1aearctic. The eye of the imago clln be hairy or not hairy sensu Hansen and Cook (l9lS); that is, visible trichia between the lenses (ommatidia) surpass the height of these lenses in the hairy eyed but do not elCceed this height when the term not hairy is used. Furthermore, the term naked means that no obvious trichia at x400 can be seen between the lenses of the eye. The use of the term inferior voseUa (IVo) (Saether 1980; fig. 16) means any differential media) bulge or protrusion(s) of thegonocoKite that originates proximally, that has its distal end somewhat free or obviously pendulous, ·and that possesses on the distal portion at least, medium long, perpendicular setae. The aedeagus sensu Saether (19BO) and Hansen and Cook (1976), or the dorsal piece sensu Serra-Tosio (lg7la) is termed superior volsella. A secondary ·branch, the "penis", is termed the median volsella. It is noticeable only in the sister genera Potthastia and Sympotthastia. Leg (fore, mid, and hind), venarum, and ratios of palp. length (segments 2-5) to fa~ial width arc eKpressed as percent. Many descriptors arc taken from Serra-Tosio {196B, 1970, 1971a, 1976). The reader is referred to Serra-Tosio (1968 or 1971a) and Hansen and Cook (1976) for their exccllent hypogygial drawings. The pupal key uses Pngast (1947) and Ferrarese and Rossaro (19B1), and many pupal descriptions can be found in Serra-Tosio (1971a). Usually male exuviae are keyed. Female pupae ar·e generally a little larger, with anal lobe more square, and 3 with genital suas squarish and not extending to caudal margin. All diagnostic features nre expeated to be the same as in the mille. The pupa, Q. sp • .I (Pagast, 1947), is apPllrently Q.geminllta Kief. not Q. aependiaulata Lundst. The laconic descriptions of the male, pupa, and lllrva of Q. nppendiculala by Makarchenko (1978) prevent one from discerning its generic status. Its pupa Ilpparently ralls between the two major groups se.parated in couplet 1, .i.e., near Sympotthastia but with some charllcters of PseudokierCeriella. Makarchenko (personal comm.) has recently submitted a paper that will elevate this unique species to a new genus, Arctodiamesa. Not inclUded in the larval key because of incomplete descriptions are two species in Pankratova (1970). Q. carpatica Botn.et C.-Cure, similar to that found in Roback (1957) as Q. near fl1lva, is suspected to be near f.gaedii; Q. heterodentata Botn. et C.-Cure appears to be an undescribed species of Sympotthastia. Diagnoses used to separate the Diamesini at ·each life state from the other tribes of Chironom idae are placed in preface to each ·of the generic keys. The utilitarian part of each key couplet occurs first with supplemental descr·iptive information following in parentheses. This extra descriptive shOUld not be needed to key a specimen. It was included to provide a rather complete generic description obtainable by back-keying and to contnin all descriptive within easy reach to minimize identification errors. Figures by the author were traced mostly Crom photomicrographs, or they were drawn using an ocular grid. Care was taken to ensure tha t the relative form, size and placement of structures were correct. However, the pupal shagreen has been some- what schematized. The keys use the terminology of Saether (1980).