Recent Submissions
Phylogenetic assessment of Megacoelium spinicavum Thatcher & Varella, 1981 (Digenea: Haploporidae) from Pterygoplichthys pardalis (Siluriformes: Loricariidae) in the Peruvian Amazon Basin
(Journal of Helminthology, 2026-01-08) Chero, Jhon Darly; Ñacari, L.; Yunis Aguinaga, Jefferson; Murrieta Morey, Germán; Cruces, Celso Luis; Huaman, N.; Cacique, E.; Lopez, D.; Mondragón Martínez, Aarón; Martínez Rojas, Rosa
This study provides the first integrative analysis of Megacoelium spinicavum Thatcher & Varella, 1981 (Digenea: Haploporidae) from the Amazon sailfin catfish Pterygoplichthys pardalis Castelnau, 1855 (Siluriformes: Loricariidae) in the Peruvian Amazon. A detailed morphological description is presented, including the first scanning electron microscopy (SEM) images of tegumental structures, which revealed two distinct types of tegumental spines: (1) small, button-
like spines and (2) sharply pointed spines. Partial sequences of the 28S rDNA and mitochondrial cox1 genes were generated and analysed to investigate the phylogenetic position of Megacoelium Szidat, 1954, within the Haploporidae Nicoll, 1914. Phylogenetic analyses placed M. spinicavum within the ‘robust species’ clade of Saccocoelioides Szidat, 1954, clustering with S. bacilliformis Szidat, 1973, although with weak support. These results provide additional evidence that Saccocoelioides is not monophyletic and support restricting the genus to the ‘minute species’ clade containing the type species. The ‘robust species’ clade appears to comprise at least three divergent lineages, potentially representing distinct genera, one of which includes M. spinica-
vum. The absence of molecular data for M. plecostomi Szidat, 1954, the type species of Megacoelium, continues to obscure its phylogenetic placement. We highlight the need for comprehensive morphological and multilocus molecular analyses, including SEM, to clarify the taxonomic status of Megacoelium and to resolve the evolutionary relationships of chalcino-rematine digeneans in Neotropical fishes.
A new, conspicuously pigmented Pyrrhulina (Teleostei: Characiformes: Lebiasinidae) from the Río Tigre, Loreto, Peru
(Journal of Fish Biology, 2026-01-29) Ferreira Netto, Andre; Vieira, Lorena; Souza, Taina; Ruiz Tafur, Morgan; García Ayala, James
A new species of Pyrrhulina is described based on morphological and molecular evi-dence. Pyrrhulina punctata is distinguished from all congeners by the presence of a series of 7 to 16 irregular blotches of dark pigmentation on the flanks, equally marked in juveniles and adult specimens, the presence of 26–28 lateral-line scales, 17–21 maxillary teeth, 23–25 outer premaxillary teeth, 40–41 inner premaxillary teeth and 23 outer dentary teeth, the distinctly elongate rays on dorsal, pelvic and anal fin on adult males, the presence of irregular dark marks on the basal portion of anal-fin rays and intervening membranes, and the presence of a second dark blotch on the distal tip of longest dorsal-fin rays. The molecular data indicate a closer relationship with Pyrrhulina spilota, corroborating the morphological evidence and the shared coloura- tion pattern. Besides the diagnostic characters allowing the recognition of both species, their distinction was corroborated by all species delimitation algorithms [Assemble Species by Automatic Partitioning (ASAP), Poisson Tree Processes (PTP) and Generalized Mixed Yule Coalescence (GMYC)] employed herein. In addition, the occurrence of P. spilota in the Madeira basin is refuted as the registers were based on
misidentifications of Pyrrhulina vittata.
Species functional traits affect regional and local dominance across western Amazonian forests
(Journal of Ecology, 2026-12-09) Mata Granados, Laura; Fortunel, Claire; Cayuela, Luis; de Aledo, Julia G.; Ben Saadi, Celina; Kraft, Nathan Jared Boardman; Baraloto, Christopher; Wright, Joseph S.; Vleminckx, Jason; Garwood, Nancy C.; Hietz, Peter; Metz, Margaret R.; Draper, Frederick C.; Baker, Timithy R.; Phillips, Oliver L.; Honorio Coronado, Eurídice N.; Ruokolainen, Kalle; García Villacorta, Roosevelt; Roucoux, Katherine H.; Guèze, Maximilien; Valderrama Sandoval, Elvis; Fine, Paul; Amasifuen Guerra, Carlos A.; Zarate Gomez, Ricardo; Stevenson, Pablo R.; Monteagudo Mendoza, Abel; Vasquez Martinez, Rodolfo; Terborgh, John; Disney, Mathias; Brienen, Roel; Núñez Vargas, Percy; Aguila Pasquel, Jhon; Malhi, Yadvinder; Socolar, Jacob B.; Flores Llampazo, Gerardo; Vega Arenas, Jim; Galiano Cabrera, Darcy; Silva Espejo, Javier; Talbot, Joey; Vinceti, Barbara; Reyna Huaymacari, José; Ballón Falcón, Cecili; Feldpausch, Ted R.; Swamy, Varun; Grandez Rios, Julio M.; Macía, Manuel J.
1. Several studies have documented dominance by few species in Amazonian forests. Dominant species tend to be either locally abundant (local dominants) or
regionally frequent (widespread dominants) but rarely both (oligarchs). Here, we explore relationships between dominance and functional traits. We ask whether: (i) dominance is associated with specific functional profiles and (ii) dominance patterns (local vs. widespread dominants) are associated with different functional traits. 2. We combined census data from 503 forest inventory plots across four lowland forest habitats in western Amazonia with trait information for ~2600 tree species, encompassing data collected in the focal plots and data from published sources. We considered traits that relate to leaf, wood, seed and whole-plant strategies: specific leaf area (SLA), leaf area (LA), N content per unit leaf mass (LN), wood density (WD), seed mass (SM) and maximum diameter at breast height (DBHmax).m 3. Our results reveal that dominant species display different trait combinations depending on the habitat type. Taller dominant species exhibit higher regional frequency, associated with higher dispersal ability and lower local abundance, likely due to negative density dependence. Greater SM contributes to higher regional frequency of dominant species via greater dispersal by birds and mammals and seedling survival. Finally, traits related to resource conservation strategies, such as lower SLA, LA, LN and greater WD, favour higher local densities across most habitats, while the opposite pattern was linked to higher regional frequency. 4. Synthesis. Our findings reveal that (i) dominance is associated with different functional traits depending on the habitat type, and (ii) different functional trait values define distinct dominance patterns. Our study exemplifies the potential of trait-based approaches to illuminate the ecological mechanisms that may underlie dominance in tropical forests. Finally, accounting for both local abundance and regional frequency when studying dominance is likely to improve our understanding and forecasting of how different species will respond to global change drivers in western Amazonia.
Holocene patterns of peat accumulation in Peruvian Amazonia
(Elsevier, 2026-03-15) Lawson, Ian T.; Åkesson, Christine M.; Dargie, Greta C.; del Águila Pasquel, Jhon; Draper, Frederick C.; Hastie, Adam; Kelly, Thomas J.; Sassoon, D.; Abraham, V.; Baker, Timothy R.; Fabel, D.; Gulliver, P.; Honorio Coronado, Eurídice; Roucoux, Katherine H.
Peatlands accumulate and store carbon over centuries to tens of millennia. Analysing the age structure of peatlands helps us to understand their genesis, development, and stability as carbon stores, and informs peatland management. Here we analyse new and previously published radiocarbon dates from peatlands in the Pastaza-Maran ̃on ́ Basin in Peru, the largest known peatland complex in Amazonia. We show that peatlands here are younger (< c. 8900 and frequently <2500 years old) than in many other parts of the tropics. Basal peat ages in extant peatlands vary depending on the geomorphological stability of the landscape, with younger basal dates typically occurring close to active river floodplains and older basal dates in more stable contexts. The data indicate that within individual peatlands, peat initiation may occur synchronously across a basin, or peat may spread laterally from one or more nucleation sites. Only two out of seven well-dated records show clear hiatuses in past peat accumulation, suggesting that carbon sequestration in some, but not all peatlands has been vulnerable to landscape hydrological change or climate change. Peatland ecosystems in the region are economically important sources of non-timber forest products, which it may be possible to harvest sustainably without biomass loss or drainage, but our analysis indicates that the peat itself accumulates too slowly to be considered as a renewable resource on economically meaningful timescales.
Integrative taxonomy uncovers Clinostomum chaacci and an unidentified congeneric metacercaria infecting Hoplosternum littorale (Siluriformes: Callichthyidae) in the Peruvian Amazon Basin
(Elsevier, 2025-11-27) Chero, Jhon Darly; Ñacari, L.A.; Murrieta Morey, Germán; Cruces, Celso Luis; Cacique, E.; Huaman, N.; Lopez, D.; Mondragón-Martínez, Aarón; Martínez-Rojas, Rosa; Yunis Aguinaga, Jefferson
Clinostomum Leidy, 1856 is a cosmopolitan genus of digenean trematodes whose metacercariae commonly infect freshwater fishes and amphibians as second intermediate hosts. In South America, the diversity and taxonomy of Clinostomum metacercariae remain poorly understood, due in part to the morphological similarity of larval stages and the scarcity of molecular data. This study provides the first integrative evidence of two phylogenetically distinct Clinostomum lineages infecting the callichthyid catfish Hoplosternum littorale (Hancock, 1828) (Siluriformes: Callich- thyidae), a benthic catfish of commercial and subsistence importance in the Peruvian Amazon. Morphological analyses (light and scanning electron microscopy) combined with molecular data from mitochondrial (cox1) and nuclear (28S rDNA) market revealed two lineages with clear genetic differentiation. Specimens from Loreto were conspecific with Clinostomum chaacci Sereno-Uribe, Lopez-Jim ́ ́enez, Gonz ́alez-García, Ortega-Olivares & García-Varela, 2025, previously re-ported from several fish hosts across Central and South America, whereas those from Ucayali formed a distinct and highly divergent lineage (11.9–12.7 % cox1 divergence) closely related to Clinostomum L1, representing a potentially undescribed species. The detection of C. chaacci in H. littorale constitutes a new host record and expands the known distribution of this species to the western Amazon Basin. The detection of Clinostomum metacercariae in fish muscle tissue raises potential zoonotic concerns, especially in regions where raw or undercooked fish is consumed. These findings underscore the need for integrative taxonomic approaches to unravel hidden