Pacific Coast Of Panama Research Articles

Molecular phylogeny of Boninia (Platyhelminthes: Polycladida), with description of a new species from the Pacific coasts of Panama.

Mesopsammic polyclad members in the family Boniniidae have attracted attention in terms of their evolutionary shifts of microhabitat and their unique morphology such as a pair of pointed tentacles extending from the anterolateral margins and prostatoid organs harbouring stylets. Here, we establish a new species of this family as Boninia panamensis sp. nov. from the Pacific coasts of Panama, based on its morphological characteristics of (i) four cerebral and 61-80 marginal eyespots, (ii) two prostatoid organs located anterior and posterior to the penis papilla, and (iii) two uterine canals departing from the anterior part of the Lang's vesicle. We also report Boninia cf. uru from Hawai'i, USA, based on its morphological identity with B. uru from Okinawa, Japan, along with their genetic distances for the partial cytochrome c oxidase subunit I (COI ) sequences, which were beyond the range of intraspecific differences observed in congeners in this study. Boninia oaxaquensis is also reported from Panama as a new locality for the species. Involving the above-mentioned three species sequenced herein, we reconstructed molecular phylogenetic trees of Boninia based on the four gene markers (18S rDNA, 28S rDNA, 16S rDNA and COI ). Our phylogenetic trees indicated the synapomorphy within the genus Boninia of the small numbers of stylets (2-4) and the connection route of the uterine canals to the Lang's vesicle. The results also showed a characteristic distribution pattern in which pairs of species in distinct lineages occurred sympatrically with different microhabitats, as observed in Boninia uru and Boninia yambarensis in Okinawa and B. panamensis sp. nov. and B. oaxaquensis in Panama. In addition, we discuss possible speciation pathways in this genus based on the tree topology. ZooBank: urn:lsid:zoobank.org:pub:D414BACD-C14A-4B34-8AF9-7ACBA28F46D0.

Carbon Stocks in Two Aquatic Marshes on the Caribbean and Pacific Coast of Panama

Wetlands are critical ecosystems globally, boasting significant ecological and economic value. They play a crucial role in the hydrological cycle by storing water and carbon, thereby helping to mitigate climate variability. But in Panama, little is known about the carbon stored in freshwater wetlands. This research presents the estimation of the carbon stocks of two freshwater wetlands in Panama, located on both sides of the Caribbean (Portobelo) and Pacific (Tonosi) coasts. The methodology consisted of transects of 125 m and 40 m wide, with six circular plots every 25 m; in each transect, the diameter of the tree trunk was measured at breast height (1.3 m) and the species was recorded, and in the same plots, soil samples were collected in triplicate by depth intervals. The average total ecosystem carbon storage (TECS) for the aquatic wetlands of Tonosí was 106.26 ± 18.3 Mg C ha−1, and for Portobelo, it was 355.09 ± 70.02 Mg C ha−1. These recorded values can contribute to the conservation of wetlands, supporting Panama’s nationally determined NDC contributions. However, despite the acceptance that wetlands are important nature-based solutions, national data on soil carbon stocks in freshwater wetlands are still scarce and their protection should be increased.

First record of the deep-sea anglerfish Ceratias uranoscopus Murray, 1877 (Lophiiformes, Ceratiidae) from the Tropical Eastern Pacific Ocean

n 1973, a specimen of the deep‑sea anglerfish Ceratias uranoscopus Murray, 1877 was collected at a depth of 1000 m off the Pacific coast of Panama. This specimen represents (1) the first verified occurrence record of this species and genus in the Tropical Eastern Pacific Ocean and (2) an extension of about 7000 km east on this species’ previously known distribution. In this contribution, we provide and discuss unpublished and comparative morphometric, meristic, and occurrence data, corroborating the identity of the specimen and species and validating the new geographic range.

First Record of Parasphaerosyllis malimalii (Polychaeta: Syllidae) from Gorgona Island (Colombian Pacific)

A new species of polychaete, Parasphaerosyllis malimalii (Syllidae), inhabiting coral colonies of Pocillopora spp. was described on Coiba Island (Pacific coast of Panama) by Capa et al. (2001a). To improve its description and provide additional ecological remarks, 73 specimens of P. malimalii, found in dead fragments of Pocillopora spp. in two research projects on bioerosion in Gorgona Island (Colombian Pacific coast), between March 1998 and December 1999, and June 2015 and August 2018, were examined and measured. The average (±SD) length (in mm) of the specimens from the first (n=38) and second (n=35) projects were 2.84 (0.42) and 8.86 (3.24) respectively. The largest specimen was collected in the second project and measured 15.4 mm. The pygidium of this species has a pair of cirri slightly thicker and longer than the parapodial cirrus. These polychaetes are mostly dead coral inhabitants, nesting in vacant galleries left by borers. With this record, the distribution range of P. malimalii is extended southward to Gorgona Island. We are confident that this species must inhabit other coral reefs in the area, so we propose that the distribution of this species must be circumscribed to the Tropical Eastern Pacific.

Characterizing oceanographic conditions near Coiba Island and Pacific Panama using 20 years of satellite-based wind stress, SST and chlorophyll-a measurements

Coiba Island and the associated Special Zone of Marine Protection represent an important, yet poorly studied marine reserve along the Pacific coast of Panama. While efforts have recently began to establish monitoring programs in the region, a range of historical, marine-related environmental measurements already exist, derived from satellite-based observations. The goal of this paper was to use long-term datasets for key variables to provide qualitative insights (i.e. descriptive oceanography) of climatological conditions and interannual variability in the Pacific Panama region. These are underpinned with numerical assessments, providing an important baseline for ongoing and future studies, particularly in the Coiba Island/Gulf of Chiriqui region. In particular, we examined 20 years (January 2003-December 2022) of wind stress, sea surface temperature (SST), and chlorophyll-a (Chl-a), spanning the neritic and pelagic regions of the Pacific Panama coast. During the dry season (northern winter), the well-known, seasonal, regional Panama wind jet appeared across the Gulf of Panama, leading to surface mixing and SST cooling that eventually extended across most of the Panama Bight. West of the Azuero Peninsula, SST increased and surface warming extended further offshore from January through April. The SST in the Gulf of Chiriqui during this period was about 1 °C warmer on average than east of Coiba Island. By July and August, offshore SST gradients became largely longitudinal, cooling occured across the season, and the SST on either side of Coiba Island was nearly the same. The influence of the Panama jet in the Gulf of Panama was clear in the Chl-a data as well, with upwelling-driven values peaking in February/March (up to 11 mg m-3, with a monthly climatological value of around 2 mg m-3 during this period). During the rest of the year, the Chl-a concentration in this region averaged around 0.5-1.0 mg m-3. In the Gulf of Chiriqui and the region east of Coiba Island, the climatological monthly averages were roughly 0.3-0.5 mg m-3 and 0.4-0.6 mg m-3, respectively. Somewhat surprisingly, very high Chl-a values were present in the satellite data for the Gulf of Chiriqui during May 2007 and June 2008, peaking at 16 mg m-3 and 32 mg m-3 at a location just west of Coiba Island, respectively. It remains unclear as to the cause of these apparent blooms. Even when the high Chl-a values were excluded in the calculation of climatological averages in the Gulf of Chiriqui, however, there is a suggestion of modest seasonality in Chl-a values, with slightly elevated values (~ 0.4 mg m-3) peaking around May and October. During the extreme El Niño event of 2015-2016, the monthly-averaged SST along the Panama Pacific coast was warmer than average, with elevated levels of up to + 2 °C and lasting 12 months in the Gulf of Chiriqui. In the Gulf of Panama, the monthly-averaged SST anomalies were up to + 1.7 °C, although the temperatures returned to near-seasonal averages after roughly 5 months.

First mercury and stable isotope assessment from an unusual mass stranding of rough-toothed dolphins (Steno bredanensis) (Artiodactyla: Delphinidae) in Azuero peninsula, Pacific coast of Panama

Introduction: Small cetaceans are good bioindicators of environmental contamination; however, knowledge about their ecotoxicological status in Central America is scarce. In Panama, access to samples from wild populations to determine the ecotoxicological status of oceanic dolphins is limited; therefore, stranding events provide an alternative for obtaining samples. In April 2016, a rare mass stranding event occurred in the Azuero Peninsula (Pacific coast of Panama), where 60 rough-toothed dolphins (Steno bredanensis) stranded, including ten which died on the beach.
 Objective: To assess total mercury (THg) concentrations, and δ13C and δ15N stable isotope values in rough-toothed dolphins for the first time in this region.
 Methods: Nine skin samples were collected from adults, stored in 70 % ethanol, and posteriorly analyzed to determine THg concentrations and stable isotope values.
 Results: THg concentrations ranged from 4 764 to 18 689 ng g-1 dry weight (dw) (mean = 12 841; SD = 5 083 ng g-1 dw), δ13C values ranged between −16.8 and −15.2 ‰ (mean = −16.2; SD = 0.6 ‰), and δ15N values ranged between 14.3 and 15.9 ‰ (mean = 15.0; SD = 0.5 ‰).
 Conclusions: High THg concentrations reported for this species in the Azuero Peninsula are consistent with values reported for rough-toothed dolphins in other areas worldwide, such as the central-northern Rio de Janeiro State in Brazil and La Guajira in the Colombian Caribbean. Elevated mercury (Hg) concentrations may be related to the rough-toothed dolphin diet, which according to δ15N values found here, appears to be based mainly on high trophic level prey that bioaccumulate more Hg in their tissues compared to lower trophic level organisms. However, additional dietary studies would be required to support these findings. Continuing monitoring of traditional dietary analysis, as well as contamination levels in fish and dolphins, is necessary to understand the dolphins’ ecotoxicology in Panama.

Bryde’s Whale (Balaenoptera edeni brydei, Artiodactyla: Balaenopteridae) aggregation area in the Gulf of Chiriqui, Panama

Introduction: Even though they occur worldwide in tropical and subtropical waters, Bryde’s whales (Balaenoptera edeni) are one of the most enigmatic of all the balaenopterid species. Previous research has reported the presence of Bryde’s whales off the Pacific coast of Panama, but little is known about their behaviors, abundance, and distribution in these waters.
 Objective: We report on an area in the Gulf of Chiriqui, Panama, where Bryde’s whales have regularly been sighted.
 Methods: We conducted small-boat surveys for marine mammals in the Gulf of Chiriqui between 2001 and 2022, during both the austral (26 300 km) and boreal (4 700 km) winter seasons.
 Results: We made 25 sightings of 33 Bryde’s whales. Sightings were made in nine of the years surveyed, and most were in the austral winter season (92 %). Most sightings were of one animal (80 %), and one sighting was of a mother-calf-escort trio. The aggregation area appears near the Contreras Islands, where most sightings (84 %) were made. We have photo-identified 14 individual whales using the dorsal fin. One individual has been sighted over two years (2014 and 2015), while the remaining have been documented only once. No photographic matches have been made to other areas.
 Conclusions: The persistent use of this aggregation area could indicate it is used for foraging, and the presence of a calf may indicate the area is also used for reproduction. The one inter-annual resight suggests this area may be used repeatedly by some of the same animals. Further research is needed off Panama to better understand this population of Bryde’s whales, its conservation status, and its relationship to the broader eastern tropical Pacific populations. Expanding the marine protected areas in the Gulf of Chiriqui may be warranted in order to protect this aggregation area.

The life cycle of the Neotropical water strider Telmatometra withei in different salinity environments

ABSTRACT Telmatometra withei (Bergroth, 1908) is a common water strider found across the Neotropics. Although, the taxonomy of T. withei is relatively well known, the specie’s life cycle has not been characterized. We use field surveys and laboratory experiments to describe the life cycle of two populations of T. withei in the Pacific coast of Panama. Specifically, we compared the life cycle between fresh and brackish water populations known to show local adaptation to each environment. We also contrast the life cycle of T. withei with that of other water striders previously reported in the literature. We found that the average life cycle of T. withei is approximately 66.7 days, and this period did not vary significantly between fresh (65.0 days) and brackish (68.3 days) populations. However, these estimates were longer than those reported for other species of water strides. In addition, traits associated with reproductive success such as egg length and fecundity varied significantly between populations, with females from freshwater populations showing larger values. This suggests that salinity can have important consequences for reproductive traits in T. withei, even if the overall life cycle may not be affected by salinity. Thus, characterizing the life history of these Neotropical organisms is crucial to understand the rich freshwater biodiversity of this region, as well as its response to both natural and anthropogenic disturbances.

New species of Polycystididae (Platyhelminthes: Kalyptorhynchia) from Cuba and the Pacific coast of Panama

Four new species of marine polycystidid microturbellarians (Platyhelminthes, Kalyptorhynchia) are described from Cuba and Panama. These species are Brachyrhynchoides ortizi sp. nov., Djeziraia adriani sp. nov., Phonorhynchoides lalanai sp. nov., and Sabulirhynchus ibarrae sp. nov. All species occur in Cuba, and P. lalanai sp. nov. was also retrieved from the Pacific coast of Panama. From the latter locality, we also report Sabulirhynchus axi Artois & Schockaert, 2000. All species are readily distinguished from their congeners by the morphology of the sclerotised structures of the male genital system. The prostatic stylet of B. ortizi sp. nov. is the shortest and widest known for Brachyrhynchoides. Djeziraia adriani sp. nov. can be recognized by its paired seminal vesicles and S-shaped prostate stylet. The prostatic stylet of P. lalanai sp. nov. is proximally twisted and the length proportion between its accessory and prostatic stylet is the largest among all known species of Phonorhynchoides. Sabulirhynchus axi and Sabulirhynchus ibarrae sp. nov. are morphologically similar, yet the latter species is unique due to the characteristic ridge in the middle of the proximally tubular prostatic stylet. With the data available today, a possible explanation of rhabdocoel biogeographic patterns across the Isthmus of Panama remains largely speculative.

Sediment depth and accretion shape belowground mangrove carbon stocks across a range of climatic and geologic settings

AbstractEstimating the long‐term sedimentary carbon sinks of mangroves and other blue carbon ecosystems has rapidly become a focus of coastal research and conservation attention. Sampling coverage, however, remains low, with sediment cores sparsely distributed across a subset of mangrove environmental settings globally. Furthermore, the ecological and geological drivers of variation in these stocks remain incompletely understood. We assessed the limits of mangrove sedimentary carbon storage by sampling sediments in diverse mangrove environments across four geographic areas: the volcanic Galapagos, the arid Baja Peninsula, and the geologically and climatically distinct Caribbean and Pacific coasts of Panama. At 80 sites across these areas, we quantified the organic carbon density, sampled with depth, of entire sediment columns. Depth‐integrated carbon stocks are highly variable, from <17 to >1700 MgCorg ha−1. The positive relationship between sediment carbon density and annual rainfall demonstrated in global studies was not observed across these areas, though some carbon density differences were evident. Variation in sediment depth, ranging from 7 to 427 cm across sites, largely explained variation in carbon stock across the areas studied. These results underscore the importance of using measurements of sediment depth to estimate carbon stock. Long‐term geomorphological processes, such as the build‐up of sediment deposits shaped by coastal dynamics, play a major role in shaping mangrove carbon stocks. Investigating and accounting for these processes will enable more accurate estimation of this variable and valuable carbon pool.

The functional ecology of mangrove fishes across the Isthmus of Panama

AbstractAimBiogeographic history and variation in modern environmental conditions can greatly influence local and regional community structure and, more generally, ecosystem functioning. This is clearly exemplified at the Isthmus of Panama where marine communities and environments from the Caribbean Sea and the Tropical Eastern Pacific Ocean differ despite ancient connections during the Miocene and Pleistocene. Here, we compare the functional (implied from traits) and isotopic structure of mangrove fish communities from those two biogeographic regions, which have been separated by the Isthmus of Panama for ~3 my.LocationCaribbean and Pacific coasts of Panama (Eastern Pacific and Caribbean Sea).MethodsWe gathered data on five functional traits (salinity preference, body mass, diet, position in the water column and lifespan) of mangrove fishes from the sampled regions. We also analysed δ13C and δ15C isotopic values and calculated functional isotopic metrics of the most abundant fish species inhabiting mangroves of these two regions.ResultsThe taxonomic composition and functional and trophic diversity differed between the mangrove fish communities of the Caribbean and the Eastern Pacific. Although the species richness of both assemblages was similar, there was very little taxonomic overlap between them: Snooks (Centropomidae) numerically dominated in the Eastern Pacific, whereas grunts (Haemulidae) and snappers (Lutjanidae) dominated in the Caribbean Sea. Functional divergence (FDiv) and isotopic richness (IRic) were higher in the Caribbean than in the Eastern Pacific, indicating differences in the way fishes use mangroves in these areas.Main conclusionsTaxonomic and functional characteristics of mangrove fish assemblages across biogeographic realms can be strongly influenced by local environmental factors (e.g. tidal regimes, the presence of adjacent coastal ecosystems and productivity), and these can override similarities that recent historical connections of faunas might be expected to produce. All such aspects need to be considered when seeking generalizations about ecosystem functioning.

Recent observations of Dermochelys coriacea (Vandelli, 1761), in the waters of Pacific Panama

The situation of the Eastern Tropical Pacific subpopulation of the leatherback sea turtle (Dermochelys coriacea) is critical due to the drastic declines of nesting females. Evidence of the presence of leatherback sea turtles along the Pacific coast of Panama is anecdotal and is based on the local knowledge of local residents. I present here an uncommon observation of a subadult and an adult D. coriacea in the waters off the coast of Azuero Peninsula in central Panama. These observations indicate the need for intensive surveys along this coast that in part may rely on key local informants to urgently implement conservation efforts for this species.

Ecology, behavior, and vocalizations of the Coiba Spinetail (Cranioleuca dissita), a Panama endemic

The Coiba Spinetail (Cranioleuca dissita), endemic to Islas Coiba and Ranchería on the Pacific coast of Panama, was originally classified as a subspecies (C. d. dissita) of the geographically distant Rusty-backed Spinetail (C. vulpina) of South America, but its status has long been an enigma. The present study was conducted to obtain basic information on the ecology, behavior, and vocalizations of this species, which has previously been lacking. On both islands, Coiba Spinetail was found almost exclusively in forest and forest edge. Their most common foraging substrate was small-diameter (∼1 cm) branches or vines, although they also foraged on tree trunks. The foraging type most often observed was pecking, but probing and gleaning were also observed regularly. The most common foraging height was 7–10 m above the ground, although they foraged as low as 2 m and as high as 25 m. The nest of Coiba Spinetail, which has not been previously described, is a globe-shaped structure made mostly of plant fibers and built around a vertical support such as an upright branch or trunk or around several lianas or vines. The nest of Rusty-backed Spinetail instead is a globular mass of grass, roots, and sticks, wedged in the fork of a partly submerged sapling or bush. The song of Coiba Spinetail resembles typical Cranioleuca spp. in having several short introductory notes followed by a series of notes on one pitch. It differs from most species in the genus, however, in that the notes gradually become longer and slow down, rather than accelerating or being evenly spaced. The song differs markedly from that of Rusty-backed Spinetail in note structure and quality. These results coupled with previous findings that Coiba Spinetail is genetically distinct from Rusty-backed Spinetail indicate that it merits full species status. Considering its extremely small range, Coiba Spinetail qualifies for Near Threatened status under IUCN Red List criteria.

An annotated and illustrated checklist of the porcelain crabs of Panama (Decapoda: Anomura).

The present study is the first exhaustive checklist of porcelain crabs (Porcellanidae) distributed on the Pacific and Atlantic (Caribbean) coasts of Panama, based on literature records and material collected between 2006 and 2019. The Panamanian porcellanid fauna is currently composed of a total of 76 species, with 26 species reported from the Caribbean coast, 45 species reported from the Pacific coast, and five species reported from both sides of the Central American Isthmus (Isthmus of Panama). In other words, the Caribbean and Pacific coasts of Panama each harbour, respectively, 31 and 50 species of porcellanid crabs. However, this total includes two problematic porcellanid records from Panama, viz. Clastotoechus nodosus (Streets, 1872) and Petrolisthes brachycarpus Sivertsen, 1933, as well as a putatively undecribed taxon reported as Pachycheles sp. The following four species are recorded for the first time from Panama, viz. Euceramus panatelus Glassell, 1938, Pachycheles riisei (Stimpson, 1859) [also being new for Mexico], Petrolisthes dissimulatus Gore, 1983 and P. tonsorius Haig, 1960. In addition, Minyocerus kirki Glassell, 1938 is newly recorded from Colombia, extending its previously known distributional range significantly southwards. Most species are illustrated in colour, several for the first time, based on material from Panama or other localities. At least 20 further species (16 in the Atlantic, 5 in the Pacific, and 1 in both oceans) are suspected to occur in Panamanian waters, based on their records from the neighbouring Costa Rica and/or Colombia, or their wide distribution in the Caribbean Sea or the tropical eastern Pacific. The presence of several cryptic or pseudocryptic species (at least some of them presumably undescribed), especially in the taxonomically challenging Petrolisthes galathinus (Bosc, 1802) species complex, or the eventual species splitting within some taxa currently seen as transisthmian, will likely further increase the total number of species present in Panama. The porcellanid fauna of Panama is also ecologically remarkably diversified. Most Panamanian porcelain crabs are free-living under rocks, in crevices of rocks, dead coral heads, coralline algae, coral rubble etc., or on mud, among mangrove roots. Euceramus panatelus lives in possibly self-dug burrows in soft mud or muddy sand, whereas its congener E. transversilineatus (Lockington, 1878) may occasionally be found in association with holothuroids. At least 15 further porcellanid species occurring in Panama live in permanent or facultative associations with a variety of other marine organisms, including sponges, cnidarians (octocorals), echinoderms (sea urchins, sea stars, sea cucumbers), polychaetes (parchment worms) and other decapod crustaceans (hermit crabs), making them one of the most attractive groups for studies of symbiosis-related behaviour and evolution.

Extended depth of focus ultraviolet imaging compared with laser scanning confocal microscopy for the study of micro-Arthropoda surface texture, with the description of a new species of Brachypodopsis (Acari: Hydrachnidia).

Visualization and representation are two processes at the core of basic biodiversity studies. Visualization involves the examination, sorting, and evaluation of similarities and differences among specimens by specialists who then assign them to the same or different species. It is a cognitive process. Representing involves transmitting the knowledge obtained in the first step to others, usually specialists of the group under study, generally through written descriptions aided by representative drawings and/or images. In this work, I describe a new species of water mite, Brachypodopsis guillermoi n. sp. (Acari, Hydrachnidia), from the island of Coiba off the Pacific coast of Panama, using both laser scanning confocal microscopy and extended depth of focus microscopy with visible (wavelength: 400-700 nm) and ultraviolet (wavelength: 365 nm) light. A comparison of the surface texture representation obtained from these imaging methods suggests that extended depth of focus ultraviolet microscopy can be a cost-effective alternative to laser scanning confocal microscopy for the description of exoskeletal features of micro-arthropods.

Two new species of emTypton/em Costa, 1844 from tropical American waters, withtaxonomic notes on emT. tortugae/em McClendon, 1911 and a new record of br /emT. granulosus/em Ayón-Parente, Hendrickx amp; Galvan-Villa, 2015 (Decapoda: Caridea: Palaemonidae).

Two new species of the palaemonid shrimp genus Typton Costa, 1844 are described based on material from Panama and Mexico. Both species are closely related to T. tortugae McClendon, 1911, a species originally described from the Dry Tortugas, off southern Florida, USA, and later scarcely recorded from other western Atlantic localities, from Bermuda to Mexico and Brazil. Some clarification and additional illustrations are provided for the type material of T. tortugae. Typton jonkayei sp. nov., is described based on material from fouling-encrusting communities dominated by sponges, growing on submerged roots of the red mangrove, Rhizhophora mangle L., in Bocas del Toro, Caribbean coast of Panama. This new species differs from T. tortugae in several morphological details, for instance, on the minor and major chelipeds (second pereiopods), telson, uropod, frontal margin and ambulatory pereiopods. Typton cousteaui sp. nov. is described based on a single ovigerous female dredged in the southern Gulf of California off Baja California Sur, Mexico, previously reported as T. tortugae. This new taxon seems to represent a true cryptic species with no significant morphological divergence from the allopatrically isolated T. tortugae, except for slight morphometric differences. In addition, T. granulosus Ayón-Parente, Hendrickx Galvan-Villa, 2015 is recorded from the Pacific coast of Panama, based on material collected in the Coiba Archipelago. Some taxonomic, distributional and ecological remarks are provided for T. granulosus and the closely related T. serratus Holthuis, 1951.

Variable host responses mediate host preference in marine flatworm-snail symbioses.

Host preference of symbionts evolves from fitness trade-offs. However, it is often unclear how interspecific variations in host response traits influence this evolutionary process. Using the association between the polyclad flatworm Paraprostatum echinolittorinae and its intertidal snail hosts on the Pacific Coast of Panama, we assessed how a symbiont’s host preference is associated with varying host defenses and post-infestation performances. We first characterized the prevalence and intensity of worm infestation in five snail hosts (Tegula pellisserpentis, Nerita scabricosta, N. funiculata, Planaxis planicostatus, and Cerithium stercusmuscarum). We then used manipulative experiments to test flatworm’s host choice, hosts’ behavioral rejection of flatworms, and hosts’ growth and survival following the infestation. In the field, flatworms were orders of magnitude more prevalent and dense in T. pellisserpentis, N. scabricosta, N. funiculata than P. planicostatus and C. stercusmuscarum, although the three former hosts were not necessarily more abundant. The results from our laboratory host selection trials mirrored these patterns; flatworms were 3 to 14 times more likely to choose T. pellisserpentis, N. scabricosta, N. funiculata over P. planicostatus and C. stercusmuscarum. The less preferred hosts frequently rejected flatworms via mantle contractions and foot withdrawals, which reduced the infestation rate by 39%−67%. These behaviors were less frequent or absent in the preferred hosts. Flatworm infestation variably influenced host performances in the field, negligibly affecting the growth and survival of T. pellisserpentis and N. funiculata but reducing the growth of P. planicostatus. Flatworms thus preferred less defended hosts that can also support higher worm densities without being harmed. Stable isotope analysis further revealed that flatworms are unlikely to feed on snail tissues and may live as a commensal in their preferred hosts. Our study demonstrates that host response traits can modulate a symbiont’s host choice and calls for more explicit considerations of host response variability in host preference research.

Impacts of Whale Watching on the Behavior of Humpback Whales (Megaptera novaeangliae) in the Coast of Panama

Ecotourism focused on whales and dolphins has become a popular activity and an important source of revenue for many countries. Whale watching is vital to supporting conservation efforts and provides numerous benefits to local communities including educational opportunities and job creation. However, the sustainability of whale-based ecotourism depends on the behavior and health of whale populations and it is crucial that ecotourism industries consider the impact of their activities on whale behavior. To address this statement, we collected behavioral data (e.g., change in swimming direction, frequency of breaching, slap behaviors, diving, and spy hops) from humpback whales (Megaptera novaeangliae) in the marine protected area of Las Perlas Archipelago off the Pacific coast of Panama. The goal was to determine if tourist vessel presence had an influence on whale behaviors. We conducted this study during the humpback whale breeding season from August through September 2019. Based on 47 behavioral observations, we found that higher boat density corresponded with humpback whales’ frequency of direction changes, which based on previous literature is believed to be a sign of disturbance. Alternatively, no changes in behavior were observed with varying boat density. This result is important given Panamanian regulations first implemented in 2007 by Resolution AMD/ARAP No. 01, 2007 prohibit whale-based tourism from disturbing whales, which is explicitly measured by changes in whale behavior. Because there is no systematic monitoring of whale watching activity to enforce the regulations, there is currently little compliance from tour operators and tourists. The integration of animal behavior research into management planning should result in more effective regulation and compliance of such conservation policies.

First record of hybridization in Caranx Lacepède, 1801 (Carangidae: Perciformes) in the Tropical Eastern Pacific Ocean.

During a recreational fishing trip on May 2017 to Isla Montuosa, Pacific coast of Panama (7.467472, -82.266556; 30 m depth), a specimen belonging to the genus Caranx was captured. The specimen showed an unusual combination of external characters, intermediate among the species known to occur in the Tropical Eastern Pacific (TEP), which caught the attention of the fishermen. A detailed analysis involving traditional morphology and molecular techniques revealed that the specimen corresponds to a hybrid of the species C. melampygus and C. sexfasciatus. This represents, to the best of our knowledge, the first confirmed record of hybridization within the genus and family in the TEP and the second record for the entire Pacific Ocean.

New species of Duplominona Karling, 1966 (Platyhelminthes, Proseriata) from the Pacific coast of Panama.

Eight new species of Duplominona (Platyhelminthes, Proseriata, Monocelididae) are described from the Pacific coast of Panama. They differ from their congeners in the detailed morphology of hard structures associated with the copulatory organ. Duplominona basidilatata n. sp. has a cirrus provided with 5-6 rows of triangular spines, 3-8 μm long, with a large, flat, poorly sclerotized basis. D. hystricina n. sp. has 10-12 rows of needle-shaped spines, 3.5-15 μm long, with a swollen basis. The cirrus of D. hyperhystricina n. sp. is provided with 20-25 rows of slender spines 1.5-9 μm long, with a recurved distal tip. In D. veracruzensis n. sp., cirrus spines increase abruptly in size, from 1.5-2 μm to 6-7 μm. D. uniserta n. sp. has a very long seminal vesicle and a small cirrus, provided with one girdle of hook-shaped spines, 3-5 μm long. D. macrodon n. sp. has one girdle of large, triangular spines, 8-18 μm long. Both D. trimera n. sp. and D. pseudotrimera n. sp. have a tripartite tail, and their cirrus is provided with a stylet. In D. trimera n. sp., the stylet is surrounded by 15-20 rows of spines, 6.5-10 μm long, while D. pseudotrimera n. sp. has 6-8 rows of large spines, 7-22 μm long. D. uniserta n. sp. and D. aduncospina Curini-Galletti, 2019 from the Caribbean coast of Panama have few rows of morphologically nearly identical spines, and are possible candidates as trans-isthmian geminate species. The presence of species with a tripartite tail on both sides of the Isthmus of Panama suggests the possibility of further geminate species pairs; however, no support could be obtained on the basis of the morphology of their hard structures. Five of the eight new species of Duplominona have been found in a single locality, and the diversity of genus along the Pacific coast of Panama may be far higher than present contribution suggests.