Araneomorphae and Pseudoscorpiones from Estación de Biología Los Tuxtlas IB-UNAM

Dr. Fernando Alvarez Padilla

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This Spider Inventory of Araneomorphae includes 237 species documented with 2,514 compound images. 8,655 adult specimens were collected (4,927 females and 3,728 males) representing 39% of the total spiders. Our results show a 83% of completeness based on several non-parametric and parametric species richness estimators that vary from 312 to 424. These estimations based on 823 samples represent the spider fauna of only one hectare of forest and below two meters of height. More plots and techniques that access the canopy fauna are needed; however this is the first spider inventory for a primary Tropical Wet Forest in Mexico thoroughly documented online, collected following standardized protocols. The paper with these data and other ecological analyses will be send for publication soon.

This Spider Inventory documentation includes 281 webpages, 98% created automatically with Perl scripts and Excel formulas. These pages are static and organize these 2,514 images by species, body part, view, etc. Their html code it is very simple to minimize bugs during construction and because my skils as a programer are few and basic. More about this topic is disccused at the end of the Microscopy methods section of this website. Help is needed from a proffesional to compile a small program that makes all these automatically and with a user interface to fix errors, etc.

Los Tuxtlas Tropical Biology Station is found at the northernmost distribution of the lowland tropical rainforest in the Neotropics. It comprises 647 hectares of tropical rainforest embedded in close to 155,123 ha which are part of the Los Tuxtlas Biosphere Reserve. This field station, founded in 1967, belongs to the Institute of Biology of the National Autonomous University of Mexico (UNAM). The main objectives of the field station are research and conservation of the tropical rainforest.

Los Tuxtlas field station has been operating for over 50 years and it is one of a few in the set of field stations in the Neotropics where long-term research has been carried out on biodiversity inventories, as well as studies on plant demography, natural regeneration of the forest, physiological ecology of plants, ecological interactions between plants and animals, primate ecology, avian, amphibian and reptile ecology, and forest fragmentation, among other major research areas. The diversity of invertebrates is immense and only through more inventories we will be able to document and describe all the new species found in the region.

Sampling protocols included six methods divided by hours/person as effort unit during day and night. Collecting methods included 'beating', 'cryptic' and pitfall traps; 'looking up or aereal' and 'looking down'. In addition leaf litter was processed with 12 Berlese funnels of 45 cm in diameter and 48 pitfall traps left for five active days. For more information about these methods and sampling protocol go to the references at the Inventories Home Page.

Please contact us if you are interested in a similar website for your spider inventroy. This site construction has worked for few species of Pseodoscorpiones, but it is recomended only for spiders. Many modifications would be required for a thorough documentation of the anatomy of these arachnids; however, if the same "file naming organization" is followed it will produce a similar result as the one presented here.

These inventory pages also include seven species of Pseudoscorpiones documented with 70 images. A total of 443 specimens (174 immatures and 269 adults) were collected with Berlese funnels, cryptic searching and pitfall traps. These seven species represent a good estimate for one hectare of leaf litter, however other methods that cover their phoretic hosts are needed.

Locality data: México, Veracruz, San Andrés Tuxtla, Estación Biológica "Los Tuxtlas". 18° 34' 56.1" N, 95° 4' 32.1" W, 192 m. Plot central coordinates. Tropical Wet forest, Lab. Aracnologia FC-UNAM. Visited four times from 2016 through 2018. These four expeditons were planed taking into account the locality seasonality.

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Funding was provided by UNAM-DGAPA-PAPIIT project IN214916 Diversidad cibernética de dos grupos de arácnidos (Araneomorphae y Pseudoscorpionida) en la Selva Mediana Perennifolia de la Reserva de Los Tuxtlas.

Picture captions: Left picture: Hugo Valdes, Josué López, Dulce Piedra, Francisco Salgueiro, Fernando Alvarez, Antonio Galán and Uriel Garcilazo. Right picture: Fernando Alvarez, Antonio Galán, Dulce Piedra, Ali Lira, Ricardo Raña.


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Araneomorphae of Mexico by is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License. Based on a work at Please use of this Website is limited to research, educational, non-commercial use as defined under Creative Commons License. Colleagues are welcome to use this catalog for their individual research so long as the author and the Facultad de Ciencias, UNAM are cited as described above. Users are NOT allowed to use any of these images in their publications without explicit permission from the copyright holder