Although it has been demonstrated that environmental changes within a year can affect the reproduction, survival, and growth of invasive species, these factors have rarely been incorporated into demographic analyses. Therefore, we applied multistate demographic models (based on capture–recapture animal methods accounting for imperfect detectability of individuals in natural conditions) to evaluate the effects of reproductive phenology and rainy season on the survival and transition/retrogression rates among stage categories of black elderberry (Sambucus nigra L.)—an invasive tree species widely distributed in temperate forests of Europe and America. In the Abies religiosa temperate forest, Mexico City, a multistate demographic model of S. nigra was built using bimonthly censuses during a year. We selected the best-fitting model according to Akaike’s information criterion adjusted for small sample sizes (AICc). We determined the response of reproductive phenology of S. nigra to the rainy season for 2 yr through repeatability and phenotypic plasticity indexes. Our results showed that the reproductive phenology of S. nigra has a low repeatability index and a high phenotypic plasticity index. We demonstrated that additive and interactive effects of reproductive phenology and rainy season promote changes in survival and transition/retrogression rates among stage categories. During the rainy season, the survival probability of seedlings and transition probability toward the adult category increased. Therefore, our study represents a significant contribution to the knowledge of the demographic dynamics of invasive species on an intra-annual scale.

A new collection of fossil decapod crustaceans from the Cretaceous Rosario Formation, the Eocene Tepetate Formation and the Oligocene El Cien Formation, Baja California Sur, Mexico, has yielded two new genera and several new species, Amydrocarcinus dantei n. gen. and sp., Levicyclus tepetate n. gen. and sp., Eriosachila bajaensis n. sp., Oregonia spinifera n. sp., Archaeopus mexicanus n. sp., and Necronectes nodosa n. sp. Additionally, new occurrences of the previously described Lophoranina bishopi, Xandaros sternbergi, Icriocarcinus xestos, and Lobonotus mexicanus as well as Dardanus cf. D. mexicanus are reported. As part of ongoing work on global evolutionary and paleobiogeographic patterns within the Decapoda, the work has prompted a review and synthesis of decapod occurrences in the tropical and subtropical Americas including the southern United States, the Caribbean, Mexico, Central America, and northern South America. As a result of the systematic review, several new combinations are reported herein which include Eriosachila bartholomaeensis (Rathbun, 1919), Lobonotus sandersi (Blow and Manning, 1996; 1998), and Matutites americanus (Rathbun, 1935). Icriocarcinus is transferred to the Goneplacidae, extending the range of that family into the Cretaceous. Most Cretaceous through Miocene tropical and subtropical American taxa appear to have originated within the area and a large number were endemic. Most of the immigrants to the central Americas appear to have evolved along North Atlantic shelves and subsequently dispersed to the Americas, probably via continental shelf routes. In addition, as demonstrated by several previous studies, decapod crustaceans appear to have evolved in numerous middle- and high- latitude areas with subsequent dispersal to lower latitudes, contrary to the long held notion that the tropics are areas of origin with subsequent dispersal to other regions. Low-latitude decapod taxa tend to remain in low-latitude areas. The Maastrichtian and the Eocene appear to have been times of elevated extinctions within the Decapoda; however, the extinction patterns for those two time intervals are very complex.

Twenty-four nearly complete carapace samples were collected at three different localities of the Maastrichtian (Late Cretaceous) Cárdenas Formation in San Luis Potosí, east-central Mexico. The material has been assigned to five families: the Callianassidae, Dakoticancridae, Carcineretidae, ?Majidae, and Retroplumidae. Two genera of callianassid shrimp are described, Cheramus for the first time in the fossil record. Dakoticancer australis Rathbun is reported as the most abundant crustacean element; one new genus and species of carcineretid crab, Branchiocarcinus cornatus, is erected, and a single, fragmentary specimen is questionably referred to the Majidae. The three localities reflect paleoenvironmental differences, exhibited by different lithologies, within marginal marine, lagoon environments. The record of dakoticancrid crabs in the Cardenas Formation extends the paleobiogeographic range of the family and the genus Dakoticancer. Carcineretid crabs, although not abundant, seem to have been a persistent element of crustacean assemblages in clastic environments during the Late Cretaceous of the ancestral Gulf Coast of Mexico.

The arthropod macrofauna from the Middle Member of the lithographic limestones of the Tlayúa Formation, in quarries at Tepexi, México, is comprised of marine and nonmarine components. Marine taxa include a new species of flabelliferid isopod, a new genus and species of an anomuran, and a new genus and species of a brachyuran crab. Remains of an arachnid and an odonate nymph represent nonmarine constituents. Previous paleoenvironmental interpretations of a restricted lagoon, with periodic episodes of marine and freshwater influences are consistent with the nature of the arthropod fauna. Isopod remains, represented only by corpses, that resemble modern ectoparasites of fishes suggest that they are directly associated with the abundant fish remains found in the quarries, either as ectoparasites that released their hosts before they died or possibly as scavengers that fed on fish remains. The next most abundant arthropods are the crabs, most of which are corpses, suggesting that this group lived in or very near to the depositional site of the Tlayúa Formation. Based upon the new fossil material, the stratigraphic range for the Aeglidae has been extended to span Albian to Holocene time. Extant representatives of this family inhabit fresh water environments of South America.

Examination of extremely well-preserved cuticle samples from the Maastrichtian retroplumid crab, Costacopluma mexicana Vega and Perrilliat, collected in the Difunta Group in Nuevo León State, Mexico, documents the preservation of corpses in an anoxic microenvironment produced by decomposition of soft tissue of the organisms. All four cuticular layers, epicuticle, exocuticle, endocuticle, and membranous layer, as well as pore canals and tegumental glands, can be recognized. There is no evidence of resorption that accompanies molting. X-ray analysis of the cuticle indicates that the organic matrix was replaced by carbonate-hydroxyapatite, that the original calcitic material was replaced by quartz, and that the replacement proceeded from the outer and inner surfaces of the cuticle toward the interior. The specimens were interpreted to have been preserved in an organic-rich, restricted lagoon in which pH was changed by periodic influxes of fresh water.

Decapod crustacean specimens from the middle Eocene San Juan Formation in central Chiapas represent the first record of Eocene decapods in southern México. New taxa include: Dardanus mexicanus new species (Diogenidae), Lophoranina cristaspina new species, Notopus minutus new species (Raninidae); Verrucoides stenohedra new genus and new species (Xanthidae); Stoaplax nandachare new genus and new species (Goneplacidae); and Viapinnixa alvarezi new species (Pinnotheridae). Verrucoides verrucoides new genus and new combination from the Paleocene of Greenland represents a new combination. In addition, the fauna includes Callianassa sensu lato sp., Laeviranina sp., Calappilia cf. C. hondoensis Rathbun, 1930, Eriosachila sp., and indeterminate calappid and xanthoid taxa. This assemblage bears close relationship with coeval faunas in the Tethyan region of southern Europe and southern North America and with Paleocene faunas of Greenland, strengthening the evidence for previously described patterns of dispersal within the Decapoda.

Three species of mollusks and one annelid are described from the Paleocene upper mudstone member of the Potrerillos Formation (La Popa Basin), and from the upper part of the Rancho Nuevo Formation (Parras Basin). The species described include a gastropod, a bivalve, a nautiloid and a serpulid worm, which are formally reported for first time as Paleocene fauna of the Difunta Group in northeastern Mexico. The nautiloid species provides the basis for correlation between the two sedimentary basins of the Difunta Group, as it is reported for Paleocene layers of the two formations studied. Shoreface and tidal-flat depositional environments are inferred for the Paleocene rocks of the Difunta Group.

Twenty-three species of Campanian, Maastrichtian, Paleocene, and Eocene freshwater gastropods from northeastern Mexico are described, including eight new species: Viviparus mcbridei, Pachychilus (Pachychiloides) lawtoni, Melanoides (Melanoides) yolandae, Melanoides (Melanoides) wollebeni, Physa cepedaensis, Mesolanistes magnus, Mesolanistes murrayi, and Gyraulus zoltani. Specimens were collected from fine-grained, green sandstone and mudstone, red mudstone, and as hematized remains in fine light-brown sandstones belonging to the following stratigraphic units of northeastern Mexico: Cerro del Pueblo (Campanian, Parras Basin), Olmos (Maastrichtian, Sabinas Basin), Las Encinas (Paleocene, Parras Basin), and Carroza (Eocene, La Popa Basin) Formations. All except two of the genera (?Pyrgulifera and Mesolanistes) have recent representatives. Review of habitats of living species of the six extant genera and interpretations of sample lithologies support the inference of dominantly freshwater paleoenvironments. Only one Maastrichtian locality is interpreted confidently to have had a brackish water influence.

Three new species of freshwater gastropods are described from the lower Eocene Adjuntas Formation. Five more species are reported from the same fauna. This is the first report of Tertiary freshwater Mollusca of the Campanian–lower Eocene Difunta Group. The three new species (Hemisinus (Longiverena) reticulosus, Hemisinus (Longiverena) adjuntaensis, and Melanatria ypresiana) belong to the family Thiaridae, which today is a worldwide distributed group of freshwater gastropods of medical importance. Paleoenvironmental interpretation for red, green, and yellow beds of Adjuntas Formation suggests delta-plain deposits. Gastropods here described lived in swamps and marshes of this portion of the ancestral Gulf of Mexico.

Mexfusus rotundicostatus new genus and species is a neogastropod of uncertain affinities from the Late Cretaceous (Early Maastrichtian) Mexcala Formation of southern Mexico. It is characterized by strong, rounded, axial ribs, fine spinelets at the intersection of axial ribs and sharp spiral cords, subsutural cord, strong simple spiral cords, and an apparently smooth, glazed columellar lip. A possible second species is Peristernia conica Riedel, 1932 from the Coniacian of Cameroon.

The first formal report of Tertiary portunid crabs for Mexico is based on two new species, Portunus atecuicitli and Necronectes tajinensis, from the middle Miocene beds of the Tuxpan Formation in Veracruz, east-central Mexico. Associated crustacean remains include fragments of calappid fingers, calappid carapace fragments possibly assignable to Matuta Fabricius, and callianassid hands. Low tolerance to osmotic variations of recent species of Portunus confirms paleoenvironmental interpretations for shallow, euryhaline, tropical waters during deposition of the Tuxpan Formation.

The first Mesozoic thylacocephalans from the western hemisphere are documented from the Muhi Quarry plattenkalk in the La Negra facies of the El Doctor Formation (Albian–Cenomanian), Zimapán Area, northwestern Hidalgo, central Mexico. They all are found in a single horizon at the base of the type section. These specimens represent two new genera and species, and a third undetermined species which likely also represents a new genus and species. Victoriacaris muhiensis is a shorted-bodied thylacocephalan with concave anterior and posterior notches as well as a beveled anterior spine. Polzia eldoctorensis is trapezoidal in outline with a rounded posteroventral corner. The third undetermined species is known only from one broken specimen, but has distinctive marginal spines that are not possessed by any other post-Cambrian thylacocephalan. The occurrence of such a diverse fauna of thylacocephalans markedly increases the diversity and geographic range of Cretaceous thylacocephalans, but does not offer any insights into the tempo of thylacocephalan extinction at the end of the Cretaceous.

The discovery of platy limestone deposits in northeastern Mexico has led to the collection of well-preserved stramentids of early Turonian age from Vallecillo, state of Nuevo León, and of early Coniacian age from El Carranza, state of Coahuila. Stramentum (Stramentum) pulchellum (Sowerby, 1843) colonized the ammonite shells during the lifetime of the animals, occasionally in two subsequent generations. Colonization of the ammonite shell by Stramentum (S.) pulchellum was hindered by strong ornamentation only. The ammonites did not interfere with their epizoans. Colonization during lifetime shows that these ammonites dwelled in well-oxygenated water levels near the surface, and most stramentids were embedded alive. The known paleobiogeographic occurrence of Stramentum (S.) pulchellum and its long stratigraphic occurrence are considerably enlarged by our findings. The pseudoplanktonic mode of life of Stramentum, and attachment to ammonite shells, may have been a response of a once benthic organism to repeated oxygen-deficient conditions on the seafloor of mid-Cretaceous oceans, i.e., to oceanic anoxic events (OAEs).

More than thirty complete specimens of Carcineretes planetarius Vega, Feldmann, Ocampo, and Pope, 1997, a member of the extinct decapod family Carcineretidae, have been collected from the upper part of the Ocozocuautla Formation in Chiapas, southeast Mexico. Stratigraphic occurrences of Carcineretes in the Caribbean Province suggest that this crab should be regarded as an index fossil for the early Maastrichtian. Six samples of this species may represent individuals that died during molting. The sudden disappearance of this family at the end of the Maastrichtian and its restricted paleobiogeographic distribution in the vicinity of the impact site suggest that the Carcineretidae may have been affected by the Chicxulub impact. Other decapod specimens collected from the same localities were assigned to the Xanthidae; Parazanthopsis meyapaquensis new genus and species, and Megaxantho zoque, new genus and species, are described. They constitute the second and third reports of Cretaceous xanthid crabs from Mexico. A lagoonal paleoenvironment is suggested, based on associated fauna and flora. Occurrences of index species of benthic and planktic foraminifera along with that of diagnostic rudist species confirm an early Maastrichtian age.

Forty species of gastropods (six of them new: Calliomphalus (Planolateralus) mexcalensis, Nododelphinula diminuta, Potamides temalacensis, Ptychopotamides ancestralus, Amaurellina guerrera, and Drilluta gloriae), and 13 species of bivalves are described from the lower Maastrichtian marls of the basal Mexcala Formation from Guerrero State, southern Mexico. Age interpretation was based on planktic foraminiferans. Associated fauna includes planktic and benthic foraminiferans, ostracods, solitary corals, crustaceans, echinoids, and vertebrates. The distribution of bivalve and gastropod species suggests that this area has affinities with the Gulf Coast Plain Province of the United States, although some species also are reported from the Middle East, Europe, and South America.

Two new species of the rhynchonellid brachiopod Probolarina are described, Probolarina neoleonensis new species and Probolarina papalotensis new species. They were collected from a Paleocene limestone lens associated with a diapir in the La Popa basin, northeastern Mexico. Thousands of these brachiopods occur in this lens and constitute the first report of brachiopods for the Difunta Group, from which a diverse paleobiota has been previously reported. This occurrence represents the oldest record for the genus in the Western Hemisphere, as the only other Paleocene occurence of this genus was reported from New Zealand. Recent studies suggest that the carbonate lentil from which the brachiopods were collected were deposited in the shadow-effect area adjacent to the diapir, which affected the sediment influx into the basin.

A new species of carcineretid crab, Carcineretesplanetarius, is described from the Upper Cretaceous (lower Maastrichtian) Barton Creek Dolomite at Albion Island, Belize. The age is based on the stratigraphic range of associated nerineid gastropods and correlation with nannoplankton, benthic foraminifera, and the other known congeneric species of crab found in Jamaica. Confirmation of this age aids in constraining the timing of ejecta deposits of the Chicxulub impact found at the top of Barton Creek Dolomite exposed on Albion Island. Paleoenvironmental and paleoecological analyses suggest that these crabs were swimmers in lagoonal settings, capable of burrowing a few centimeters into the mud for protection.

Nine species, including two new species of decapod crustaceans, are described from the Paleocene Rancho Nuevo Formation, collected from two localities of the Parras Basin, southeast Coahuila state, Mexico. The astacid Enoploclytia gardnerae (Rathbun, 1935) is represented by a pair of large chelae and one cephalothorax. An incomplete nephropid carapace is identified as Enoploclytia sp. Partial specimens of a callianassid and a pagurid are described. One partial carapace representing Linuparus wilcoxensis Rathbun, 1935 is described. A new raninid, Macroacaena venturai new species extends the genus into Mexico. Paraverrucoides alabamensis (Rathbun, 1935) is the most abundant species, followed by Tehuacana tehuacana Stenzel, 1944 and Viapinnixa perrilliatae new species. Taxonomic affinities of this assemblage confirm influence of the Mississippi Embayment, particularly from Paleocene stratigraphic units of Texas and Alabama.

This paper deals with singular semilinear elliptic equations in bounded domains with Dirichlet boundary data. The elliptic operator is a second-order operator not necessarily in divergence form. We consider existence, uniqueness and linearized stability of positive solutions for a series of nonlinear eigenvalue problems.