Marilú López-Mejía

ARE THERE ADAPTATION LEVELS TO CAVE LIFE IN CRAYFISH

Abstract The stygobitic crayfish Procambarus cavernicola and Procambarus oaxacae reddelli and the epigeal crayfish Procambarus olmecorum were maintained in laboratory conditions in order to compare their oxygen consumption rates by measuring the decreasing oxygen concentration. These closely related species belong to the same subgenus and live in nearby caves and surface streams located in the same karstic region found in northern Oaxaca, Mexico. The consumption rates were monitored in laboratory conditions during fifteen hours in water maintained at 20°C without food. Significant differences among the species were found. Although these species live in similar conditions of total darkness during their life cycles, P. cavernicola had the higher oxygen consumption rate; this is a result of being slightly conditioned to oxygen partial pressures of the experimental bottle. Procambarus oaxacae reddelli showed a lower oxygen consumption rate strongly correlated to the oxygen partial pressure of the water. The epigeal P. olmecorum was used as a control and showed a consumption rate slightly conditioned to oxygen partial pressures that was lower than the consumption rate of P. cavernicola. The differences in consumption rates between the stygobitic species in relation to the characteristics of the caves where they live and their adaptation degree to cave life are discussed.

Freshwater Prawns of the Genus Macrobrachium (decapoda, Palaemonidae) with Abbreviated Development from the Papaloapan River Basin, Veracruz, Mexico: Distribution and New Species

In the Papaloapan River two freshwater prawns with abbreviated development have been recorded: Macrobrachium villalobosi (a stygobitic species) and Macrobrachium totonacum (an epigeal species). In this paper we describe four new species from this genus, and the distribution of these six species along the river basin. M. oaxacae nov. sp. occurs in the River La Junta, and together with M. cosolapaense nov. sp. is geographically close to the stygobitic species and M. totonacum, but differs from these in the following aspects: pigmentation, the number of rostral spines, and the relative proportions of the articles of the second pereiopod, of appendix masculina and appendix interna, and the number of spines on the appendix masculina. Macrobrachium mazatecum nov. sp. lives in two streams in Veracruz: the first close to Tierra Blanca Veracruz and the second on the Zapotal Veracruz near Mpio. Lerdo de Tejada. This species was also recorded in two springs near Valle Nacional Oaxaca, and differs from M. oaxacae nov. sp. and M. cosolapaense nov. sp. in the number of rostral spines, and the relative proportions on the articles of second pereiopod, of appendix masculina and appendix interna, and of the spines on the appendix masculina. Finally, Macrobrachium jacatepecense nov. sp. occurs only in a spring near Jacatepec, Oaxaca. This species differs from the other species in the relative proportions of the articles of the second pereiopod: however, it is very close to Macrobrachium oaxacae nov. sp. in the number of rostral spines, but based on the geographical distribution of both species and other features, it is clearly a different species. In this Papaloapan River basin, the distribution of this complex of species is very limited, because the various populations live in very restricted areas associated with springs or small streams, and without direct interconnections. All these new species are comparable with the epigeal Macrobrachium species in the southeast of Mexico that have abbreviated larval development.

Progressive troglomorphism of ambulatory and sensory appendages in three Mexican cave decapods

Sensory and ambulatory appendages were compared between epigeal and cave species of prawn and crayfish from Mexico. The cave prawn Macrobrachium villalobosi was compared with the epigeal M. totonacum. The cave crayfish Procambarus cavernicola and P. oaxacae reddelli were compared with the epigeal P. olmecorum. In both Macrobrachium and Procambarus the antennules and antennae of the cave species were longer in proportion to carapace length than in epigeal species. In the crayfish the cave species had a longer and narrower first pereiopod, and also showed a greater development of setation on the antennules, antennae, and carapace. These are all considered examples of progressive troglomorphism. They will improve non‐visual sensory capability in the aphotic and resource‐poor cave environment.

Phylogenetic evidence from freshwater crayfishes that cave adaptation is not an evolutionary dead-end

Caves are perceived as isolated, extreme habitats with a uniquely specialized biota, which long ago led to the idea that caves are “evolutionary dead‐ends.” This implies that cave‐adapted taxa may be doomed for extinction before they can diversify or transition to a more stable state. However, this hypothesis has not been explicitly tested in a phylogenetic framework with multiple independently evolved cave‐dwelling groups. Here, we use the freshwater crayfish, a group with dozens of cave‐dwelling species in multiple lineages, as a system to test this hypothesis. We consider historical patterns of lineage diversification and habitat transition as well as current patterns of geographic range size. We find that while cave‐dwelling lineages have small relative range sizes and rarely transition back to the surface, they exhibit remarkably similar diversification patterns to those of other habitat types and appear to be able to maintain a diversity of lineages through time. This suggests that cave adaptation is not a “dead‐end” for freshwater crayfish, which has positive implications for our understanding of biodiversity and conservation in cave habitats.

Morphological adaptations to anchialine environments in species of five shrimp families (Barbouria yanezi, Agostocaris bozanici, Procaris mexicana, Calliasmata nohochi and Typhlatya pearsei)

Anchialine systems are unusual among aquatic habitats in that they are subterranean karst systems in which marine and overlying groundwater are separated by distinct haloclines and characterized by high sulphur content, darkness and low nutrient availability. In this study, we examine how the antennulae, antennae, eyes and integument morphology of five anchialine species of decapods (Barbouria yanezi, Agostocaris bozanici, Procaris mexicana, Calliasmata nohochi and Typhlatya pearsei) are adapted for anchialine environments. Our examination of sensorial structures shows that while these species appear to have convergent adaptations for anchialine environments, degrees of specialization in antennular and antennal structures vary, with Barbouria yanezi showing the greatest setation. The eyes of all five species show pores at their tips, but only Calliasmata nohochi also exhibits setae on the eyes. We propose that these additional setae and pores function to enhance the ability of these decapods to sense mechanical and chemical stimuli in the water. In overview, these anchialine crustaceans have evolved anatomical/morphological attributes that appear to function to help detect predators, congeners, food, or refugia.

Procambarus (Ortmannicus) hidalgoensis (Crustacea: Decapoda: Cambaridae), a new species of crayfish from Mexico

ABSTRACT A new species of crayfish from Camino a Olotla, Tlanchinol County, Hidalgo, Mexico, is described. Procambarus (Ortmannicus) hidalgoensis is most closely related to P. (O.) cuevachicae (Hobbs, 1941) and P. (O.) toltecae Hobbs, 1943, from which it can be distinguished by having a gonopod with a mesial process slightly flattened distally and directed caudodistally; a cephalic process slightly larger than the rest of the terminal elements, originating on the caudal surface; and a plate-like caudal process, exhibiting a strongly folded external part of the pleopod. The annulus ventralis in the new species is rhomboidal, with two strong crests, forming a deep V-shaped depression anteriorly, ending in a sinus in the middle region.

The abbreviated larval development of Macrobrachium totonacum Mejía, Alvarez & Hartnoll, 2003 (Decapoda, Palaemonidae), reared in the laboratory

Abbreviated larval development is described and illustrated for Macrobrachium totonacum Mejia, Alvarez & Hartnoll, 2003, a recently described freshwater prawn with three larval stages. The study is based on laboratory-reared material. Females carry 18 eggs on average, with a maximum of 28. The average egg diameter is 2.1 mm. The first larval stage has sessile eyes, and all appendages are developed except the uropods; however, the chelae on pereiopods 1 and 2, and the pleopods, are non-functional. In stage 2 the eyes are articulated, and the chelae and pleopods are functional. In stage 3 the uropods are developed. The larvae are lecithotrophic in the first two stages, and start feeding in stage 3. The larval development of this species is compared with other Mexican and South American species of Macrobrachium with abbreviated development: it has the same number of stages as M. vicconi Roman, Ortega & Mejia, 2000, another Mexican species. El desarrollo larval abreviado es descrito e ilustrado para Macrobrachium totonacum Mejia, Alvarez & Hartnoll, 2003, una especie de langostino recientemente descrita con tres estados larvales. Este estudio esta basado en material obtenido en laboratorio. Las hembras llevan en promedio 18 huevos y un maximo de 28. El diametro promedio del huevo es de 2,1 mm. El primer estadio larval tiene ojos sesiles y todos los apendices estan desarrollados excepto los uropodos; sin embargo, la quela de los pereiopodos 1 y 2 y los pleopodos no son funcionales. En el estado dos, los ojos estan articulados y la quela y pleopodos son funcionales. En el estado tres los uropodos estan desarrollados. Las larvas son lecitotroficas en los primeros dos estadios e inician su alimentacion en el estado tres. El desarrollo larval de esta especie es comparada con otras especies de Macrobrachium de Mexico y Sudamerica con desarrollo abreviado, esta especie tiene el mismo numero de estados que otra especie mexicana: M. vicconi Roman, Ortega & Mejia, 2000.

Freshwater Prawns (Palaemonidae: Macrobrachium) with Abbreviated Larval Development in Rivers of Mexico: Uses, Management, and Conservation Opportunities

The Macrobrachium genus in Mexico is represented by two big groups: the first one, where the larval stages are extended, and the second one, has an abbreviated larval develop‐ ment. There are three main slopes in Mexico or exorheic basins and several endorheic basins such as lakes and inner lagoons. The species with extended larval stage are M. carcinus, M. heterochirus, M. acanthurus, M. olfersii, M. hobbsi, and M. faustinum in the Atlantic and Caribbean slope, while in the Pacific slope, these species are M. american‐ um, M. occidentale, M. digueti, M. michoacanus, M. acanthochirus, and M. tenellum. These species have important fishery activities on different basins because they live from oasis in desert to main rivers in the bigger basins. However, there are some rivers that have an extended region on their upstream such as Usumacinta, Grijalva, Papaloapan, and Coatzacoalcos basins that in general are considered as hydrological regions. Just in these extended regions, there are more caves in freshwater, springs, and primary or secon‐ dary streams, which are covered by short area rivers, and in these places, there are the following species: M. totonacum, M. tuxtlaense, M. oaxacae, M. cosolapaense, M. oaxacae, M. jacatepecense, M. mazatecum, and M. vicconi, while in the cave are M. villalobosi, M. acherontium, and M. sbordonii. However, for these species, the uses are more for the local groups mainly indigenous cultures such as Mayan, Lacandon, Zapotecs and Mixtecs, and others, and their commercial use is only in the local region depending on where these species are distributed.

EL DESARROLLO SUSTENTABLE Y LA INSTRUMENTACIÓN DEL PARADIGMA EN MÉXICO

Through this paper we aim to illustrate the latest proposals within EU legislation regarding airports, which are facing some difficulties in the EU legislative iter of approval. Airports, due to the liberalization and deregulation process, shifted from an appendix facility of air transport into a self-standing industry. The whole process was imprinted by the massive privatization and is leading now into a competitive and common market, at least in EU level. These proposals, regarding slot allocation, groundhandling and procedure for restriction of the noise related operations, are to be considered as a serious effort for a comprehensive regulation. In our view, de lege ferenda it is a welcome initiative which yet represents difficulties in reaching uniformity within Union airport market. Furthermore, it is time for the Commission to launch new package related to the State Aids in the Air Transport sector and specifically, those which deals with airports.