Search

The ichnospecies Cuniculonomus parallelus Givulescu, 1984 and Stigmellites serpentina Kozlov, 1988 are recorded for the first time in Argentina and the new ichnospecies Cuniculonomus saltensis n. ichnosp., Stigmellites vitatus n. ichnosp. and Stigmellites pervenae n. ichnosp. are defined from two Miocene localities: Peñas Blancas and Quebrada del Horno, from northwestern Argentina. A set of characters to identify fossil linear mines is provided as well as five ichnotaxobases to differentiate the ichnogenera Cuniculonomus, Stigmellites and Phytomyzites. Two ichnospecies are now revised and included in Phytomyzites: P. arcuata (Krassilov, 2008a) comb. nov. (Ophionoma) and P. crucitracta (Krassilov, 2008a) comb. nov. (Troponoma). Finally, a review of fossil record of linear mines is provided. [ABSTRACT FROM AUTHOR]

Oxaea austera nests in hard, red lateritic soils with dense grass cover. Some characters of Oxaea austera nests conform to the known architecture of the oxaeine nests such as the long, vertical shaft and the radiating, horizontal tunnels connected to vertical cells. The presence of more than one cell per lateral, cells at different depths containing larvae at different stages, and discrete walls in the main and laterals are described for the first time for Oxaeinae. One cell was located at the end of each lateral with others (2-4) near them, in some cases arranged in a row just beneath the lateral. Cells are oriented vertically and consist of a chamber, a spiral closure and an antechamber connected with a lateral. The chamber and antechamber are surrounded by a thick discrete wall. Each nest was occupied by at least two active females indicating communal nesting. They also contained older cells, suggesting the reutilization of the nests by successive generations. Both behaviors may be a response to the difficulties of excavation in hard soils. Communal nesting may be also a defensive behavior against nest cleptoparasites. The shape, size, discrete walls of lateritic soil material, spiral closure, and antechamber of O. austera cells closely resemble the fossil bee cells included in the ichnogenus Palmiraichnus from the early Eocene Asencio Formation of Uruguay. This new evidence reinforces the proposal of extinct representatives of Oxaeinae as it constructor. [ABSTRACT FROM AUTHOR]

The new ichnospecies Celliforma curvata is described to include curved fossil bee cells from Argentina, Uruguay and the USA. The upper part of the cell (neck) of the new ichnospecies is curved, and accordingly, it can be attributed to bees of the subfamily Diphaglossinae ( Colletidae). The oldest record of C. curvata, from the early Eocene of North America (52-49 Ma), provides a minimum age for the appearance of this subfamily, in accordance with an already proposed calibrated phylogeny. It is also proposed that these fossil cells could be used for future calibrations of molecular clocks. C. curvata indicates that Diphaglossinae had a widespread distribution, from southern Utah to extra- Andean Patagonia at 42° S. In contrast, extant representatives reach only 38° S in this region. Diphaglossinae were more extended southwards in the past thanks to better environmental conditions in extra- Andean Patagonia. [ABSTRACT FROM AUTHOR]

The nests of Cadeguala albopilosa (Spinola, 1851), Diphaglossa gayi Spinola, 1851, Ptiloglossa tarsata (Friese, 1900), Ptiloglossa matutina (Schrottky, 1904) and Zikanapis tucumana (Moure, 1945) (Colletidae, Diphaglossinae) from Argentina and Chile are described herein. They show similar features to those of other Diphaglossinae: they consist of a main tunnel, cells disposed radially, isolated or in pairs, and connected to the main tunnel by laterals ones. Main tunnels are mostly vertical in species nesting in soil surface but horizontal to inclined in D. gayi, which nests in banks. Cells are vertical with curved necks. The cells of C. albopilosa show less curved necks (less than 90°), whereas in the remaining four species the cell neck is highly curved (90° or more). Cells of P. tarsata have a spiral earthen closure and a wad cottonlike material, whereas in P. matutina only had the last one. In the remaining studied species any type of closure were found. Cocoons of C. albopilosa and P. tarsata are coriaceous showing a closure composed of three disks. Zikanapis tucumana and possibly P. matutina showed dim-light foraging. The remaining species are diurnal. The climate in their nesting sites is highly diverse, ranging from 8°C to 20°C in mean annual temperature, and from 250 mm to 3000 mm in mean annual precipitation. Only C. albopilosa and, to a lesser extent, Z. tucumana nested gregariously. Zikanapis tucumana and P. tarsata were observed visiting flowers of Solanum. [ABSTRACT FROM AUTHOR]

A new species of Trichothurgus, described herein, T. bolitophilus sp. n., nests in dry horse manure pads in Chubut, Patagonia, Argentina. The simplest nests consisted of one main tunnel ending in a series of 2 cells without partitions between them. In the more complex ones up to 6 cells were connected laterally to the main tunnel. Nests showed signs of reutilization. The behavior of nesting in horse manure is described for the first time in bees. [ABSTRACT FROM AUTHOR]