Matskási István (szerk.): A Magyar Természettudományi Múzeum évkönyve 86. (Budapest 1994)

Bálint, Zs. ; Johnson, K.: Polyommatine lycaenids of the oreal biome in the Neotropics, part II: The Itylos section (Lepidoptera: Lycaenidae, Polyommatinae)

Monophyly - Methodology: We unite Itylos and Ityloides into a separate Neotropical entity (namely, the itylos section [Ityloides in synonymy]) within the tribe Polyommatine and characterize it below according to the terminology and criteria of ELIOT (1973). We have indicated above our view of characters in members of this Itylos section. These appear to obviate any validity of Ityloides as monobasic sister genus of Itylos for the following reasons. There is probably only one factual criterion in phylogenetic systematics by which BALLETTO's Ityloides might be considered noncongeneric with this assemblage. This would include documentation of a sister species sharing the generic characters of Ityloides (but differing from I. fumosus) and which, with its sister, comprised a lineage of equal cladistic rank with the other members of Itylos s. str. (e.g. pnin and the titicaca complex). Another possibility for recognizing Ityloides is entirely methodological. This would include documentation that the characters of I. fumosus itself comprise, in comparison to all other Itylos, the apotypic sister lineage as distinguished by at least one autapomorphy (as in the case of recognition of monobasic Pseudochrysops NABOKOV, 1945). At present there are two problems. First, since all members of Itylos as herein defined show autapomorphies, one could recognize Ityloides as a genus only if a separate genus was erected for each species in this small clade. Second, it appears that the titicaca complex is the more apotypic member of the group. Further, the case does not compare to the quadrad of polyommatines containing Hemiargus HÜBNER, [1818], Cyclargus NABOKOV, 1945, Echinargus NABOKOV, 1945 and Pseudochrysops. Here, all the genera are diverse except the apotypic lineage (monotypic Pseudochrysops, which also shows an unequivocal sister group of equal rank within the rest of the four taxon statement) (JOHNSON & BÁLINT in prep.). Contrasting the tightknit members of our Itylos section, most systematists agree generically lumping Hemiargus, Cyclargus, Echinargus and Pseudochrysops simply because of overall monophyly largely obfuscates character and biogeographic relationships within this speciose group (see SMITH, MILLER & MILLER, in press). Finally, and again contrasting the situation of /. fumosus, the monobasic unit of Pseudochrysops has recently been shown to occur on more than one major crustal block of the Greater Antilles. Thus, when elaborated, this population may comprise the sister species of P. bornoi (COMSTOCK and HUNTINGTON, 1943) and remove Pseudochrysops from scrutiny as a monotypic unit. DISCUSSION Generic Limits of Itylos as Herein Defined and Consideration of Outg roups - Itylos can be characterized by (1) very long uncus with produced tegumen Suspensorium absent, (2) valvae strongly sclerotized and with unique shape amongst polyommatines (exceedingly small and squat, equalling about half of the entire penis), (3) strong and robust penis with highly developed suprazonal element. These character states occur in all the known Itylos species and were properly described by NABOKOV for the titicaca complex in his generic description of Parachilades (NABOKOV 1945: 6-10). In his text NABOKOV made comparisons mainly with Chilades MOORE, 1861 taxa, suggesting some parallel evolutionary processes affecting the male genitalic structures enumerated above as character states. E. cyanea and E. sylphis have a similar valval shape but the costal valval rostellum, as well as the anal valval process, show another kind of structural shape (BÁLINT & JOHNSON 1994, Figs 31-32). The structure of penis in Itylos is also unique among the South American and austral polyommatine lycaenids. All other known South American polyommatine are structurally very different, none appearing to be a likely sister group. The Itylos section, Phylogenetic Considerations and Placement According to the Criteria of ELIOT - According to ELIOT (1973: 450) Itylos shares the following diagnostic characters of the Polyommatus section: