The Ecitoninae ants (Hymenoptera: Formicidae) from Morelos, México

To produce an inventory of the Ecitoninae ants from Morelos State (south central Mexico), we used direct capture and pit-fall traps. Occasionally, males were also collected near artificial light sources. Fifteen species were found: Labidus coecus, L. praedator s. str, Neivamyrmex agilis, N. cornutus, N fallax, N. graciellae, N. impudens, N. macropterus, N. melanocephalus, N. nigrescens, N. opacithorax, N. pauxilus, N. sumichrasti, N. swainsoni and Nomamyrmex esenbecki mordax. Twelve of these species are new records for the state. The most abundant species were L. coecus, N. melanocephalus, N. nigrescens and N. esenbecki mordax. The distribution of the species in the state, flight dates of males for some species, and a key for the identification of workers and males are included. One additional species (N. fuscipennis), collected by other authors in Morelos but not by us, is also included in the key.     

Argia mayi, a new species from México (Zygoptera: Coenagrionidae)

A new species of Argia is illustrated and described from material collected in the states of Colima, Guerrero, Jalisco, Michoacán, Morelos and Oaxaca, México. Argia mayi n. sp. is morphologically similar to Argia pocomana Calvert. It differs from the latter by the morphology of the abdominal appendages in the males and by having four postquadrangular cells in FW in both sexes, blue on the dorsum of males restricted to S8-9 and an erect hind margin of the mesostigmal plate in females.     

Two new species of Echinobothrium (Cestoidea: Diphyllidea) from myliobatiform elasmobranchs in the Gulf of California, México

Two new species of diphyllidean cestodes, Echinobothrium mexicanum n. sp., and Echinobothrium fautleyae n. sp., are described, the former from the spiral intestines of the bat rays Myliobatis californicus and Myliobatis longirostris and the latter from the spiral intestine of the cownose ray Rhinoptera steindachneri, all caught in the Gulf of California, México. Echinobothrium mexicanum is most easily distinguished from the majority of the species of the genus by the number of large apical hooks in each dorsoventral group (23) and from the remainder in the number of lateral hooklets in each group on the scolex. Echinobothrium fautleyae differs conspicuously from all other members of the genus in that the first and last lateral hooklets in each group are distinctly larger than the other hooklets in each group. Serial sections of the scoleces of these 2 new species confirm that the attachment structures on the scolex are bothria, rather than bothridia, as has been described in other species in the genus, suggesting that the attachment structures of the scolex should be examined in more detail in the genus in general. Palmate microtriches of various forms cover the proximal bothrial surfaces of both new species and are also found on the dorsal bothrial surfaces of E. fautleyae. The distal bothrial surfaces of E. mexicanum are covered with slender spiniform and short filiform microtriches. The cephalic peduncles of both species possess short filiform microtriches only. Comparison of these 2 new species with the other 3 species in this genus that have been examined with SEM suggests that the various forms and distributions of these microtriches is unique in each of these 2 species. We believe these features will prove to be taxonomically useful.     

Cytogenetic variability and differentiation in Artemia (Branchiopoda: Anostraca) populations from the Yucatán Peninsula,México

Chromosome numbers in somatic (naupliar) and germinal (adult male) cells of bisexual Artemia populations from the Yucatán Peninsula, SE México (Celestun, CEL; Chuburna, CHUB; Xtampu, XTAM; and Las Coloradas, COL), were compared to those from San Francisco Bay (SFB) and Great Salt Lake (GSL) individuals. Diploid and haploid counts permitted a double-check on results. SFB and GSL samples had low variability in number of chromosomes, with strong modal values of 2n=42 and n=21, typical for A. franciscana. Chromosome counts in the Yucatán brine shrimp samples indicated deviations from the normal 2n=42 karyotype (heteroploidy): COL had chromosome modes of 2n=42 and n=21; CEL of 2n=40 and n=20; CHUB had 2n=44 and n=22; XTAM 2n=48 and n=24. Chromocenter abundance (heterocromatic blocks of highly repetitive DNA) among populations indicated that the North American brine shrimp from SFB and GSL had a mean of 15.9 and 15.1 chromocenters, respectively. From the Yucatán brine shrimp, COL had a variable number of chromocenters, ranging from 5 to 15 with a mean value of 9.9. The other three Artemia populations had much fewer chromocenters (CEL 1–3, XTAM 1–8, and CHUB 1–4). Heteromorphic sex chromosomes were apparent in some Yucatán karyotypes preparations. The haplotype condition in the Yucatán Artemia populations, though similar to that found in some Italian A. salina populations, is reported for the first time in New World Artemia. This cytological characteristic of the Yucatán Artemia, in conjunction with their morphological and allozyme differentiation, could provide new insight for the role of chromosome rearrangements in the evolutionary process of Artemia in the New World.     

Mimosa nanchititlana,a new species from the state of México,Mexico (Mimosaceae)

AMimosa remarkable for the combination of spicate inflorescences and non-articulate pods is described from the southwestern part of the state of México and figured; its known distribution is given and its relationships discussed; diagnostic characters of known sympatric species ofMimosa are listed.     

Megapitaria squalida (Bivalvia: Veneridae) fishery landings and temperature relationship in Bahía de la Paz, México

The clam Megapitaria squalida is a fishing resource with increasing importance in Northwestern Mexico. Nevertheless, this fishery has shown important variations that could be related to environmental factors. To assess this, monthly landings of M. squalida were analyzed during 2002-2005 for Bahía de La Paz, B.C.S., and were related with monthly time series of sea surface temperature, derived from MODIS-Aqua Sensor. The results showed a positive and significant relationship between sea surface temperature and clam landings. The likely impact of anomalous conditions of sea temperature on this resource is discussed.     

Growth of the Pacific jack Caranx caninus (Pisces: Carangidae) from the coast of Colima, México

The Pacific jack Caranx caninus is a common species fished by artisanal fishermen off the coast of Colima, México. During 2002, monthly samples of morphometric data and otoliths were taken to determine age and growth. Seven age groups were identified. The highest growth, 14.4 cm, takes place during the first year of life. During the second year, C caninus grows 11.76 cm; the third year 9.61 cm; the fourth 7.85 cm; the fifth 6.41 cm and sixth year 5.24 cm. The constants of von Bertalanffy's growth equation were: L(infinity) = 83.26 cm, W(infinity) = 18.138 g, K = 0.202, t(0) = -0.283 and A(0.95) = 15 years. Growth curves of other species of the same genus were calculated in order to compare them with the one obtained in the present work. The gonadosomatic index presented higher values during November and May. The periods of more intensive feeding are from August to February.     

A fossil stemmiulid millipede (Diplopoda: Stemmiulida) from the Miocene amber of Simojovel,Chiapas, México

A fossil millipede representative of the order Stemmiulida is described on the basis of a well-preserved adult female trapped in amber from the Miocene of Simojovel, Chiapas, south-eastern México. The fossil specimen is named as Parastemmiulus elektron, a new genus and species. As observed in extant stemmiulids, this fossil shows a reduced number of ocelli, the distal larger than the proximal, as well as a total of 46 trunk segments including 2 apodous segments in front of the telson. The head of this ancient stemmiulid has three ocelli and a Tömösváry organ, characteristics not reported before in Stemmiulida, requiring the diagnosis of the order to be emended.http://zoobank.org/urn:lsid:zoobank.org:pub:361400A8-37D4-421F-B4FD-A0AE63BE538C     

Hermaphroditism in two populations of Chiton articulatus (Mollusca: Polyplacophora) from the eastern tropical coast of México

Through histological analyses, this study reveals an unusually high incidence of hermaphroditism in Chiton articulatus. Specimens were sampled every 30?days between September 2010 and September 2011 at two locations (Las Brisas and Jaramillo beaches, Acapulco) on the tropical eastern Pacific coast of Mexico. At both sites, hermaphroditism was found throughout the year, although in varying proportions. Higher percentages of hermaphroditism were found during the pre-spawning summer months (Las Brisas Beach 63%, Jaramillo Beach 68%). Two different kinds of hermaphroditic gonads were found, showing a preponderance of either male or female tissues but, commonly, female tissues occupied the greatest part of the gonad cross sections. Similar to other species of polyplacophorans, there was a predominance of males, although M:F sex ratios ranged from 0.7 to 4.5: 1 at Las Brisas Beach and 0.3–8: 1 at Jaramillo Beach.     

Monogeneans in introduced and native cichlids in México: evidence for transfer

We examined 2 cichlid fish species native to México, Cichlasoma callolepis and C. fenestratum, and 2 introduced African cichlids, Oreochromis aureus and O. niloticus, from 3 localities in southeastern México for monogeneans. Six monogenean species infected the African cichlids: Cichlidogyrus haplochromii, C. dossoui, C. longicornis longicornis, C. sclerosus, C. tilapiae, and Enterogyrus malmbergi. We found all these parasite species, except C. haplochromii and C. dossoui, on the native C. fenestratum and C. callolepis. Prevalences of Cichlidogyrus spp. were 3-10% and abundances ranged from 0.03 +/- 0.2 to 0.1 +/- 0.3 for native cichlids. We only recovered a single E. malmbergi from 1 C. callolepis. We found Sciadicleithrum bravohollisae, a monogenean of native Cichlasoma spp., on the gills of the introduced O. aureus from Lake Catemaco (prevalence 3%, abundance 0.03 +/- 0.2). Although prevalence and abundance in atypical hosts were fairly low, the present findings provide evidence of monogenean transfer from African to American cichlids and vice versa. This is the first record of exotic monogeneans in the genus Cichlidogyrus and Enterogyrus infecting native American cichlid fish. It is also the first record from southeastern México of a native American monogenean infecting introduced African cichlids.     

Somatic production of two species: Crassostrea virginica and Ischadium recurvum Bivalvia in Mecoacán, Tabasco, México

The Mexican oyster fishery, 90% supported by the coastal lagoons of the Gulf of Mexico, has decreased drastically in the last six years as a result of anthropogenic pollution and improper management. The mussel Ischadium recurvum has proliferated and competes with oysters for space and probably food. Crassostrea virginica and Ischadium recurvum were studied to evaluate somatic production with biometry and physiological condition indices (PCI's) during an annual cycle. A random sample of 200 organisms was taken montly for each species. Condition indices wet flesh weigth: wet shell weight ratio (WFW/WSW), dry flesh weight: wet flesh weight ratio (DFW/WFW), dry flesh wet: dry shell weight ratio (DFW/DSW), and ash free dry weight: tissue dry weight (AFDW/TDW) were calculated. In order to stablish physiological condition and temporal variability, these indices were compared between species and months. The somatic production of mussels was higher than in oysters. This enhancement in production could be explained by: 1) Mussel uses less energy for shell production, 2) a constant recruitment of mussel almost year-round, and 3) the mesohalin lagoon was more favourable to the mussel.     

Factors influencing the geographical distribution of Dendroctonus rhizophagus (Coleoptera: Curculionidae: Scolytinae) in the Sierra Madre Occidental, México

The bark beetle, Dendroctonus rhizophagus Thomas & Bright, is endemic to the Sierra Madre Occidental (SMOC) in México. This bark beetle is a major pest of the seedlings and young saplings of several pine species that are of prime importance to the nation's forest industry. Despite the significance of this bark beetle as a pest, its biology, ecology, and distribution are poorly known. Three predictive modeling approaches were used as a first approximation to identify bioclimatic variables related to the presence of D. rhizophagus in the SMOC and to obtain maps of its potential distribution within the SMOC, which is a morphotectonic province. Our results suggest that the bark beetle could have an almost continuous distribution throughout the major mountain ranges of the SMOC. This beetle has a relatively narrow ecological niche with respect to some temperature and precipitation variables and inhabits areas with climatic conditions that are unique from those usually prevalent in the SMOC. However, the bark beetle has a broad ecological niche with respect to the number of hosts that it attacks. At the macro-scale level, the D. rhizophagus distribution occurs within the wider distribution of its main hosts. The limit of the geographical distribution of this bark beetle coincides with the maximum temperature isotherms. Our results imply a preference for temperate habitats, which leads to the hypothesis that even minor changes in climate may have significant effects on its distribution and abundance.     

New microsatellite loci for estimating genetic diversity and structure in Octopus hubbsorum from Nayarit,México

Background

Octopus hubbsorum Berry, 1953 is the most important species for commercial fishing in the Mexican Pacific. However, there is a lack of information regarding population structure that could have important management implications. We tested 44 microsatellite loci in O. hubbsorum by cross-amplification from O. bimaculatus.

Methods and results

Genetic diversity and structure was tested over 30 octopus sampled from Santa Cruz de Miramar (Nayarit, México). A total of 11 loci were successfully amplified. All loci were polymorphic with the number of effective alleles ranging from 2.13 to 23.14, while three loci significantly deviated from Hardy-Weinberg equilibrium. No significant LD was observed between pairs of loci (P?≥?0.05). The application of the new markers in a O. hubbsorum population from Santa Cruz de Miramar Nayarit, México, did not showed Wahlund or isolate breaking effects due to the mixing of distinct populations.

Conclusions

The loci were useful to estimate levels of pairwise relatedness and to discard the presence of recent demographic bottlenecks in the population. We consider that eight microsatellites are adequate from the 11 amplified loci

     

Oceanographic conditions and diversity of sea stars (Echinodermata: Asteroidea) in the Gulf of California, México

Species richness is one of the best indicators of biodiversity. However, there are few investigations on concordance of diversity patterns and environmental settings for marine regions. The objectives of this study were to correlate species richness of shallow water (< 200 m deep) sea stars with key oceanographic factors in the Gulf of California, México, and to predict species richness of Asteroidea using multiple regressions. In these analyses the Gulf was divided into nine sections of one degree in latitude (from 23-31 degrees N), at each section we recorded: continental shelf area (at 100 and 200 m depth), temperature mean and range at three depth levels (0, 60 and 120 m), thermocline depth, surface nutrient concentrations (nitrates, phosphates and silicates), surface photosynthetic pigment concentration, and integrated productivity. Sea star species richness at each latitudinal section was estimated from literature data, new collections and museum records. Species were assigned to one of the following feeding guilds: predators of small mobile invertebrates (I), detritivores (D), predators of colonial organisms (C), generalist carnivores (G), and planktivores (P). There are 47 shallow water asteroid species in the Gulf of California (16 I, 15 D, eight C, six G, one P and one not assigned). Total species richness and guild species richness showed strong latitudinal attenuation patterns and were higher in the southernmost Gulf, an area characterized by a narrow shelf, high temperature, and low nutrient concentrations. Species diversity for each guild was correlated to a set of oceanographic parameters: temperature, nitrate concentration, and integrated productivity were linked to richness in must cases. We detected that nutrients and surface pigments always presented negative relationships with species richness, indicating that productive environments limit asteroid diversity in the study area. Finally, the postulated regression models to estimate species richness from oceanographic data were significant and highly precise. We conclude that species richness of Asteroidea in the Gulf of California is related to oceanographic conditions and can be estimated from regional oceanographic information.     

Culture of Poecilia reticulata (Pisces: Poecilidae) in tropical water bodies, Veracruz, México

Poecilia reticulata, also known as guppy, is the most popular fish in the aquarium environment. Guppys are viviparous fish with high tolerance to extreme temperatures. The development of the offspring takes between 25 and 30 days. We developed a technology for raising guppys, which outlines infrastructure and devices for reproduction, nursery, feeding, and commercialization, evaluating the financial and technical feasibility of this technology in a case study. The complete reproductive cycle occured in floating cages with 1 mm mesh and the method was tested in a tropical lagoon in Mexico. Water quality was monitored throughout the study period (temperature, dissolved oxygen and pH levels). A marketing survey was carried out at all existing aquarium shops in Veracruz City. Data collected depict quantities demanded and offered for each species by season, place of origin, and resistance to handling. The hydrobiological characteristics were: average temperature 31.4 degrees C, dissolved oxygen 4.5 mgl(-1), and pH level 6.8. With these values we built a production function, and used it to evaluate profitability. We estimate a benefit/cost ratio of 1.16, with a net annual income of US$257.67. The system may provide two permanent jobs.     

Population dynamics of Corbicula fluminea (Bivalvia) in the Paraná River Delta (Argentina)

Benthic individuals and drifting planktonic juveniles of Corbicula fluminea were sampled in the Lower Delta of the Paraná River (Argentina) at monthly intervals between October 1995 and October 1996. Densities of settled clams above 1 mm, around 300–1000 ind. m-2, varied little throughout the year. Below 1 mm benthic juveniles, on the other hand, showed a single conspicuous abundance peak in October-November (up to 1722 ind. m-2), and were practically absent during the rest of the year (overall annual mean: 1070 ± 797 ind. m-2). Drifting juveniles showed one major peak in December 1995 (160 ind. m^-3), and a minor one at the end of March (24 ind. m^-3). Length-frequency analyses of the monthly field data clearly indicate a highly structured population with a single well defined reproduction period centered on October–November. Population parameters derived from the seasonally oscillating version of von Bertalanffy's growth formula were as follows: maximum shell length: 32 mm (maximum observed shell length: 33 mm); growth constant: 0.65; growth seasonality (i.e., span of summer-to-winter growth-rate difference): 0.7; winter point (i.e., time of the year when growth is minimum): 0.5 (June–July); estimated size range for one year-old individuals: 15.3–22.4 mm; for two years: 23.5–27 mm, and three years: 27.5–29.3 mm. Comparison with previous data confirm the influence of water temperature on the clam's reproduction and growth and furnish additional evidence suggesting that food availability may be as important for recruitment as thermic regimes. Contrasts between traits of the population analyzed herein with those described previously from a nearby (ca. 10 km) site more influenced by industrial pollution point at the influence of water quality on Corbicula's recruitment and growth. This revised version was published online in July 2006 with corrections to the Cover Date.     

Therodamas Krøyer, 1863 (Copepoda: Ergasilidae) from the Piauí River estuary,State of Sergipe,Brazil

The pre-metamorphic female of Therodamas serrani Krøyer, 1863 is described for the first time based on new material collected from the upper reaches of Piauí River estuary, northeastern Brazil. Females are present in the plankton throughout the year, and are common during the rainy season. Five of the six currently accepted species of Therodamas are known only from metamorphic females, making identification of pre-metamorphic stages problematic. Identification of T. serrani was made on the basis of the leg setation and the very similar proportions of the two apical endopodal spines on leg 1.