Cibyra yumiko, Mielke & Grehan & Koike, 2025

Mielke, Carlos G. C., Grehan, John R. & Koike, Ricardo M., 2025, Review of the genus Cibyra Walker (Lepidoptera: Hepialoidea: Hepialidae) with descriptions of twenty-four new species from Brazil and Argentina, Zootaxa 5709 (1), pp. 1-74 : 66-71

Cibyra munona species-group

Five species with a wide disjunction between two reciprocally allopatric species in the south ( C. munona , C. yumiko sp. nov.), and three species in the north, where one is localized and disjunct ( C. serra sp. nov.), overlapping the tracks of C. agnes sp. nov. and C. alina sp. nov. (Plate 32, Fig. 4a ). This pattern is consistent with ancestral allopatry followed by range expansion between C. agnes sp. nov. and C. alina sp. nov. The disjunction between the southern and northern parts of the species-group range may be the result of marine incursion over former habitat now submerged (Plate 32, Fig. 4b ).

Monotypic species-groups

In addition to the western C. yungas species-group noted above, there are two eastern monotypic species-groups along the Atlantic coast: C. julie sp. nov. is localized to the southern range of C. dorita (Pl. 27, Fig. 1 ), and C. jurate sp. nov. has a broad range to the northeast (Pl. 27, Fig. 2 ) that overlaps several other species-groups. In the absence of a resolved phylogeny, the biogeography of these two monotypic groups is not assessed further here.

Distribution and tectonics

The geographic range of Cibyra has a disjunct distribution between the eastern central Andes and southeastern Brazil. The eastern species are found within the Serra da Mantiqueira, Serra do Mar, and Serra do Espinhaço ranges, separated from the Andean species by the lowlands of the Andean foreland basins and the Palaeozoic-Mesozoic Chaco-Paraná basin. The eastern range comprises 37 of the 41 Cibyra species (Pl. 33, Fig. 1 ). This concentration of species is known as the main massing of diversity. It is a biogeographic characteristic found in many animal and plant taxa globally that is indicative of both ancestral biological (genetic) diversity and the influence of historical events that have promoted differentiation ( Craw et al. 1999, Heads 2012). The most prominent historical event influencing the geology, geography, and topography of the region occupied by the main massing of Cibyra is the formation of the Atlantic Ocean.

PLATE 30. FIGURES 1–3 . Distributions and origins of Cibyra species-groups: left column (a)–spatial relationships mapped as minimum spanning tree line graphs (tracks), right column (b)–ancestral allopatry consistent with present day distributions, suggesting areas of current overlap are the result of subsequent range expansion.

PLATE 31. FIGURES 1–3 . Distributions and origins of Cibyra species-groups: left column (a)–spatial relationships mapped as minimum spanning tree line graphs (tracks), right column (b)–ancestral allopatry consistent with present day distributions, suggesting areas of current overlap are the result of subsequent range expansion.

The Atlantic basin was initiated by the emergence of the Atlantic spreading ridge that pushed up the adjacent landscapes during the Barremian-Aptian Cretaceous (129–113 Ma). As the shoulders of this uplift were displaced west and east, the coastal region of southeastern Brazil was subject to 200 km of erosion inland to the current Serra da Mantiqueira. This onshore erosion resulted in further flexural uplift along the continental margin. This geological retreat of the Brazilian coastline would have had a profound impact on the distributions of coastal organisms ( Heads 2012). As this retreat took place, it would have carried biota with it, and as the seaward edge of the continent was eventually drowned, its biota may evade drowning by surviving on the new mountains, and migrating inland on the retreating scarp. During phases of rifting and uplift, habitats would be subject to repeated marine inundation and orogeny, resulting in range expansion and hybridism. This paleogeographic history may result in disjunctions along the Atlantic coast, such as monkeys in the genus Leontopithecus Lesson , due to loss of former populations in regions that became completely submerged ( Heads 2012, 2016). The erosion and inundation of coastal regions could result in taxa that were originally allopatric ‘piling up’ on top of each other. We suggest this process could be responsible for the present-day overlapping species-groups of Cibyra as ancestral species migrated with the retreating coastline into areas already occupied by the ancestors of other species-groups (Pl. 33, Fig. 2 ). This process, beginning from the time of original rifting, continues to the present day.

PLATE 32. FIGURES 1–2. 1) Distributions and origins of Cibyra species-groups: left column (a)–spatial relationships mapped as minimum spanning tree line graphs (tracks), right column (b)–ancestral allopatry consistent with present day distributions, suggesting areas of current overlap are the result of subsequent range expansion. 2) Conceptual model of ancestral (2a) Cibyra species-groups (red and blue outlines) with allopatric distributions and allopatric species within each, occupying coastal regions that have now submerged or eroded below sea level (2b), resulting in crowding and geographic overlap of extant species-groups and partial overlap of species within each species-group.

PLATE 33. FIGURES 1–2. 1) Density of Cibyra spp. arranged in a ca. 140 km x 140 km grid showing higher concentration (centre of main massing) of species between Rio de Janeiro and Santa Catarina. 2) Conceptual model of species divergence and tectonic erosion, and displacement of Cibyra spp. Top: proposed widespread ancestor (potentially one or more species) at the formation of the Atlantic Ocean, separating South America and Africa. Middle: differentiation of species associated with tectonic and geological disruption of the ancestral range. Bottom: crowding of species due to loss of habitat in coastal regions due to subsidence and erosion.

Elevation range is another biogeographic feature of Cibyra distribution (Table 1). The genus is restricted to higher elevation forest habitats. The lowest elevation is 250–300 m for the southern endemic C. yumiko sp. nov. in the Rio Grande do Sul. Next lowest elevation is 450 m (for C. ochracea , which ranges up to 1100 m). Most species elevations range from 800 m, with the highest elevations being 2600 m (two species in the Andes). The elevation ranges do not show a simple relationship with latitude. Instead of necessarily higher elevations in more northern latitudes, there is a more complex pattern. For example, in the C. monoargenteus group, the northernmost two species have ranges of 1500–2000 m ( C. elyana sp. nov.), and 1000–1400 m ( C. mariana sp. nov.). This range is similar to that found in the two southernmost species ranges of 1200–1400 m ( C. barbara sp. nov.) and 1000–1400 m ( C. ybyra ). In the C. endyra group, the northernmost species range is 1800–2200 m ( C. monique sp. nov.), but this is not much different from the more southern C. claudia sp. nov. ( 1200–2000 m) and C. endyra ( 800–1900 m) (Pl. 26, Fig. 1 ). Furthermore, the C. monique sp. nov. distribution lies within the range of C. jurate sp. nov. with an elevation range of 700–1400 m.

The region of southeastern Brazil has undergone phases of tectonic uplift, especially resulting from the initial Atlantic spreading ridge, and subsequent flexural uplift. Since there is no direct relationship between altitudinal climates (see also Heads 2012 on East Asian monkeys), the origin of the upland distribution range of Cibyra is more consistent with lowland ancestral populations being raised to higher elevations by the geological uplift. Since the higher elevation range is applicable to all species of Cibyra , it is suggested here that an ancestor of Cibyra was first geologically lifted to a higher elevation, and in this process, diverged from its sister group (unknown at present). As there is a complex history of uplift and subsidence phases, including coastal retreat, these geological processes may have influenced the individual species elevations. In summary (Pl. 33, Fig. 2 ), we propose that the Cibyra ancestor occupied a lowland range that was geologically raised to higher elevations. During this uplift, there would have been phases of orogeny that contributed to the differentiation of species-groups and species, along with coastal erosion resulting in range migration and subsequent sympatry, particularly evident for the species-groups. More recent differentiation of species within each species-group either retains ancestral allopatry or there is limited range overlap, indicating subsequent localized dispersal and range expansion.

TABLE 1. Approximate elevations of Cibyra species.

1. Cibyra ferruginosa - 800 to 1900 m 22. Cibyra pluriargenteus - 900 to 1900 m 2. Cibyra meridionalis - 150 to 1350 m 23. Cibyra simone sp. nov. - 800 to 1900 m 3. Cibyra ochracea - 450 to 1100 m 24. Cibyra danieli - 1450 m 4. Cibyra barbara sp. nov. - 1200 to 1400 m 25. Cibyra dorita - 500 to 1900 m 5. Cibyra denise sp. nov. - 900 m 26. Cibyra forsteri - 2600 m 6. Cibyra elyana sp. nov. - 1500 to 2000 m 27. Cibyra verresi - 1000 to 1400 m 7. Cibyra jane sp. nov. - 1200 to 1500 m 28. Cibyra zischkai - 2600 m 8. Cibyra mariana sp. nov. - 1800 to 2400 m 29. Cibyra jurate sp. nov. - 400 to 1400 m 9. Cibyra monoargenteus - 800 to 1400 m 30. Cibyra julie sp. nov. - 550 to 800 m 10. Cibyra regina sp. nov. - 1500 m 31. Cibyra agnes sp. nov. - 1200 to 2000 m 11. Cibyra stigmatica - 500 to 1350 m 32. Cibyra alina sp. nov. - 1000 to 1500 m 12. Cibyra tessellata - 800 to 1100 m 33. Cibyra yumiko sp. nov. - 30 to 300 m 13. Cibyra ybyra - 1000 and 1400 m 34. Cibyra munona - 650 to 1400 m 14. Cibyra yungas - 1200 to 2000 m 35. Cibyra volta sp. nov. - 1000 to 1400 m 15. Cibyra claudia sp. nov. - 1200 to 2000 m 36. Cibyra babi sp. nov. - 500 to 800 m 16. Cibyra endyra - 800 to 1900 m 37. Cibyra clara sp. nov. - 1500 to 1900 m 17. Cibyra hannelore sp. nov. - 1100 m 38. Cibyra kika sp. nov. - 700 to 800 m 18. Cibyra mirna sp. nov. - 900 to 1050 m 39. Cibyra olinda sp. nov. - 700 m 19. Cibyra monique sp. nov. - 1800 to 2200 m 40. Cibyra parana sp. nov. - 1100 m 20. Cibyra ykeyra - 600 and 1100 m 41. Cibyra piacaba sp. nov. - 1100 m 21. Cibyra bruna sp. nov. - 800 to 1050 m

The extensive geographic overlap between the Cibyra species-groups occurs along a coastal region that has experienced 200 km of coastal retreat since the original formation of the Atlantic Ocean basin in the early Cretaceous. This spatial correlation implies that Cibyra has existed from at least this time. This purely biogeographical (spatial) correlation currently has no contesting evidence for a different phylogenetic timeline, and cannot be falsified by future fossil or island calibrated molecular divergence estimates since these can only generate minimal clade ages (cf. Heads 2012). The predominant distributional pattern within each species-group is one of allopatry, which is consistent with the species having diverged allopatrically within the ancestral range of the species-group (i.e., each species diverged within its respective range within the ancestral species range). The correspondence between species-group distributional overlap and coastal retreat since early Mesozoic time implies that the ancestor of each species group also diverged allopatrically within a widespread ancestral range extending between the Andes and the Atlantic coast by early Cretaceous time. This historical reconstruction is presented here as a potential hypothesis for understanding the present-day distribution of Cibyra and its species-groups that is now open for future analysis, and corroboration or refutation.

Figures

PLATE 1. FIGURES 1−12. Cibyra spp. of ferruginosa species-group. Adults (dorsal): 1 (CGCM 33.377), 2 (CGCM 35.939), 3 (type no. 18604), 4 (CGCM 10.168), 5 (CGCM 27.547), 6 (CGCM 26.691), 7 (CGCM 23.321), 8 (CGCM 30.335), 9 (CGCM 30.343), 10 (CGCM 23.937), 11 (CGCM 42.000), 12 (CGCM 29.967). Depositories of the specimens: 1–2, 4–12 in CGCM; 3 in USNM.