Hunting on the coast: An image gallery of Rompecráneos

The Rompecráneo is a special kind of lithic artifact which was, presumably, involved in the capture of pinnipeds carried out along the Patagonian coast of Argentina during prehistoric times. Recent papers had offered some information about their morphology but up to now they are poorly studied. In order to offset this situation in a previous work we addressed their role in hunting technics developed at the archaeological locality of Punta Entrada (Santa Cruz, Argentina). This allowed us to propose that rompecráneos were used in combination with spears when hunting on the coast. With the aim of expanding this information, here we present an image gallery of some rompecráneos recovered there. Two of these pieces share a similar morphology but were made of different lithic raw materials. The other one has the appearance of a bola stone but its weight is higher than other bola stones in Patagonia. That is why it is considered a different kind of artifact. The importance of studying these kinds of artifacts is that they have the potential of providing information about the way people interacted with the different resources (biotic and abiotic) in the past so that a better understanding of human behavior can be developed. Gallery Figure 1. Geographic location of Punta Entrada. Figure 2. Rompecráneo made of andesite. The base can be seen in the lower part of the image. Weight: 593 g. Figure 3. Different view of the rompecráneo shown in Figure 2 Figure 4. Rompecráneo made of coquina. The base can be seen in the lower part of the image. Weight: 421 g. Figure 5. Different view of the rompecráneo shown in Figure 3. Figure 6. Bola stone made of andesite. Weight:1.476 kg. Figure 7. Detail of the groove of the bola stone shown in Figure 6 Figure 8. Context of recovery of bola stone presented in Figure 6.

Impact of Increased Nutrients and Lowered pH on Photosynthesis and Growth of Three Marine Phytoplankton Communities From the Coastal South West Atlantic (Patagonia, Argentina)

Effect of global change variables on the structure and photosynthesis of phytoplankton communities was evaluated in three different sites of the Patagonian coast of Argentina: enclosed bay (Puerto Madryn, PM), estuarine (Playa Unión, PU), and open waters (Isla Escondida, IE). We exposed samples to two contrasting scenarios: Present (nutrients at in situ levels) vs. Future (with lowered pH and higher nutrients inputs), and determined growth and photosynthetic responses after 2 days of acclimation. Under the Future condition phytoplankton growth was higher in the estuarine site compared to those in PM and IE. This effect was the most pronounced on large diatoms. While the increase of photosynthetic activity was not always observed in the Future scenario, the lower photosynthetic electron requirement for carbon fixation (Φe,C = ETR/PmB) in this scenario compared to the Present, suggests a more effective energy utilization. Long-term experiments were also conducted to assess the responses along a 4 days acclimation period in PU. Diatoms benefited from the Future conditions and had significantly higher growth rates than in the Present. In addition, Φe,C was lower after the acclimation period in the Future scenario, compared to the Present. Our results suggest that the availability, frequency and amount of nutrients play a key role when evaluating the effects of global change on natural phytoplankton communities. The observed changes in diatom growth under the Future scenario in PU and IE and photosynthesis may have implications in the local trophodynamics by bottom up control.

New genetic diversity for endangered bottlenose dolphin subspecies along the Argentine coast

This study analyzed mtDNA sequences of two bottlenose dolphin subspecies found along the northern Patagonian coast, Argentina: the endangered Tursiops truncatus gephyreus and the data deficient Tursiops truncatus truncatus. Three haplotypes were recovered from nine samples. The most frequent haplotype represented the coastal morph, also two haplotypes showing falcate dorsal fin, a characteristic describing the oceanic morph. This finding suggests that both morphs may exist in sympatry in Argentina. Furthermore, sampling was extended beyond the species’ previously known range, including individuals as far as seven hundred kilometers to the south. Therefore, new genetic data, despite being preliminary, hint at an unexpectedly higher genetic diversity of matrilines than previously anticipated.

Mating behavior of Patagonian octopus (Octopus tehuelchus) under laboratory conditions

Patagonian octopus (Octopus tehuelchus) is a species that holds an artisanal fishery in the northern area of the Argentine Patagonian coast and has a potential for aquaculture development. This work aimed to characterize the mating behavior of four pairs of Patagonian octopuses under laboratory conditions. Results showed that this species has a complex reproductive behavior. Remarkably, female remained inside her shelter during pre-copula, copulation and intercourse events. Male and female faced by the oral face during sexual intercourse, which lasted 3 to 5 min. The observations will contribute to the better management of the reproductive specimens of the species in captivity.

Diseases and parasites of wild and cultivated mussels along the Patagonian coast of Argentina, southwest Atlantic Ocean

A histological survey of the commercially edible mussels Mytilus platensis and M. chilensis from wild and cultivated populations along the coast of Patagonia, Argentina (42°00’ to 54°47’S), was carried out to determine their health status. Diagnostic results included 3 types of inflammatory responses (infiltrative, nodular, and encapsulation), disseminated neoplasia disease, 2 abnormal reproductive conditions (gonadal atresia and intersex), prokaryotic inclusions, protozoans, and metazoans. Pathogen prevalence and infection intensity among mussels of different sampling sites and between those of wild and cultivated populations were compared. Inflammatory responses were recorded in all mussels from all sites, while disseminated neoplasia only occurred in the most southern cultivated M. chilensis. Intracellular prokaryotic inclusions were broadly distributed in the mussels from both northern and southern Patagonian coasts. Ciliates showed the highest prevalence among wild mussels from the colder waters of Bahía Brown. Turbellaria were recorded at higher prevalence in cultured mussels (41.7%), and trematode metacercariae occurred exclusively in intertidal wild mussels. None of the parasites found appears to be a problem to the fishery or farming, although disseminated neoplasia should be monitored. In addition, we found that mytilid species coexisting with M. platensis (Aulacomya atra and Perumytilus purpuratus) at one location shared the same pathological conditions and parasites, which differed from those of M. platensis at a distant locality. These results suggest that pathological conditions and parasites were influenced more by ecological habitat factors than by the species of mussels present, based on similar parasite assemblages found among closely related mytilid hosts in the same geographical area.