Contribution to the special issue on reptile cognition: Pattern biases, but not positional cues, influence learning in the little brown skink, Scincella lateralis

Studies of many lizard species have established they are capable of learning to escape to one specific retreat out of several available retreats and will escape to it when subjected to a simulated predator attack. Recently, researchers have focused on the processes involved in learning, including what cues lizards use to learn to escape to a retreat. Previous work on the little brown skink lizard, Scincella lateralis, has shown that it is capable of learning to escape to a specific retreat when it has gained prior experience with its environment and that its performance is better when a retreat is associated with a vertical stripe local cue than when the retreat was associated with a horizontal stripe one. Here I report the results of two additional experiments undertaken to gain a better understanding of how little brown skinks react to cues in their environment. In Experiment 1, the positional cue test, I tested if little brown skinks could be trained to escape to a specific retreat when the only cue available was a positional cue that lizards could use to orient themselves by conducting a series of trials in which little brown skinks were trained to escape to the retreat to the left or the right of a vertical cylinder. Only 2 of the 16 (12.5%) little brown skinks met the learning criterion. This was not significantly different from what is expected if lizards chose their retreats at random suggesting little brown skinks are poor at learning when only a positional cue is available. In Experiment 2, the pattern bias test, I tested if the little brown skink’s superior performance learning to escape to a retreat with a vertical stripe cue in previous experiments was due to a bias for vertical stripes (or against horizontal stripes) through a series of trials in which little brown skinks had to choose between two escape retreats: one with a vertical stripe local cue and the other with a horizontal stripe local cue. A significant bias for the vertical stripe local cue retreat was found among 24 adults, but not among 12 neonates. These results suggest pattern bias among adult little brown skinks impacted the results of previous studies. The possibility that lizards may have biases for colours or shapes and that these biases may have an impact on learning studies is discussed.

New species of Pyrrhulina (Teleostei: Characiformes: Lebiasinidae) from the eastern Amazon, Pará, Brazil

ABSTRACT A new species of Pyrrhulina is described based on 60 specimens from tributaries of the rio Amazonas: rio Anapu, rio Capim, rio Guamá and rio Xingu, and coastal drainages in the state of Pará, Brazil. The new species differs from all congeners by having the primary stripe (the horizontal stripe of dark pigmentation extending posteriorly from the snout) terminating at the distal edge of the opercle. In all other species of Pyrrhulina, the primary stripe is either restricted to the snout or continues beyond the head (i.e. at least the anteriormost four scales of the lateral line series).

A new species of Moenkhausia Eigenmann, 1903 (Characiformes: Characidae) from Amazon basin, Brazil

A new species of Moenkhausia is described from tributaries of the lower Amazon basin, Pará State, Brazil. The new species is morphologically similar to Moenkhausia collettii, M. copei, and M. venerei by the presence of a dark horizontal stripe across the middle portion of the eye, a conspicuous slightly rounded humeral blotch, a dark longitudinal midlateral stripe and a dark stripe along the anal-fin base. However, the new species can be distinguished from M. collettii, M. copei, and M. venerei mainly by the number of cusps on the inner row of the premaxillary, maxillary and dentary teeth, and by the number of scales in transversal series above and below the lateral line.

A new species of Hemigrammus Gill, 1858 (Characiformes: Characidae) from the rio Madeira and rio Paraguai basins, with a redescription of H. lunatus

A new Hemigrammusis described from the rio Paraguai and rio Madeira basins, Mato Grosso and Rondônia States, Brazil. The new species is characterized by possessing a wide dark horizontal stripe across the eye, a vertically elongated humeral blotch, and 4-5 gill-rakers on upper branch and 9-10 on lower. The new species can be easily diagnosed from H. lunatus, the sympatric and morphologically most similar congener, by the shape of humeral blotch and the number of gill rakers. Data of the type material of both Hemigrammus lunatus and H. maxillaris, as well as extensive examination of specimens, allowed us to conclude that H. maxillarisis a junior subjective synonym of H. lunatus. A redescription of H. lunatus, as well as a formal restriction of its type locality, is provided. A putative monophyletic group within Hemigrammus, composed by H. barrigonae, Hemigrammus lunatus, H. machadoi new species, and H. ulreyi, named Hemigrammus lunatus group, is proposed based on overall body morphology and color pattern. Additionally, a discussion on the biogeographical relationships between the rio Paraguai and rio Guaporé basins is provided.

Research into Practice: Teaching Mathematics and Thinking

One afternoon. eleven-year-old Michael stopped by the home of an adult friend and found her nearly buried in decorating books, charts. and samples. Michael's sudden appearance at the door was a welcome sight, and he was asked to assist his friend in the process of decorating her home office. Although quite sure he knew little about interior decorating, Michael agreed to lend a hand. The friends began to measure the room and calculate the areas of the ceiling, walls, and floor. They looked at wallpaper swatch books, paint-color charts, and rug samples from various manufacturers and discussed the differences in price, the expected coverage per gallon of paint and roll of wallpaper, and the relative quality and ea e of upkeep for different products. One tyle of wallpaper they liked had a horizontal stripe and required matching. After approximating how many rolls of striped wallpaper they would need to buy, they performed a similar approximation for a design that did not require matching. They looked at carpet amples, discussed the relative merits of light and dark colors and variou styles, and considered the issue of cost versus quality with respect to durability and stain resistance. Finally, they selected a set of materials to comple te the decorating project based on cost, product quality. maintenance required, and personal preference. After helping his friend with this task for several hours, Michael departed for his home and his dinner.