Prochilodus Argenteus Research Articles

Genetic population structure of two migratory freshwater fish species (Brycon orthotaenia and Prochilodus argenteus) from the São Francisco River in Brazil and its significance for conservation

Previous genetic studies conducted with migratory fish populations from downstream of the Tres Marias dam in the Sao Francisco River Basin (Brazil) have documented the occurrence of population structuring, as reported for Brycon orthotaenia and Prochilodus argenteus, two commercially important species in this basin. We revisited the genetic structure of these species using microsatellites. B. orthotaenia was sampled during the spawning season and was analyzed using five heterologous microsatellites. P. argenteus was collected in the non-reproductive season and genetic analysis was conducted using ten species- specific microsatellites. For both species, genetic diversity between collection sites was similar. Considering B. orthotaenia, FST and RST estimates and the Bayesian analysis demonstrated significant differences between sites. Two well-defined populations were identified in the study area, indicating population structuring for this species. No significant differences were found for P. argenteus. These data provide information for knowledge regarding genetic structure of migratory fish species, which may contribute toward the conservation besides the understanding the biology and ecology of these important fishery resources.

Genetic population structure of two migratory freshwater fish species (Brycon orthotaenia and Prochilodus argenteus) from the Sao Francisco River in Brazil and its significance for conservation

Genetic population structure of two migratory freshwater fish species (Brycon orthotaenia and Prochilodus argenteus) from the Sao Francisco River in Brazil and its significance for conservation

Genetic diversity and population structure of <i>Prochilodus costatus</i> and <i>Prochilodus argenteus</i> preceding dam construction in the Paraopeba River, São Francisco River Basin, Minas Gerais, Brazil

Curimata-pioa (Prochilodus costatus) and curimatapacu (Prochilodus argenteus) are migratory fish species endemic to the Sao Francisco River Basin in Brazil. Both species play important roles in local fisheries and ecology in the Paraopeba River. A dam was recently constructed on this river and to help in the development and conservation programs, we characterized the genetic variation of both species before dam construction. Complex hypervariable repeats microsatellite was used to asses genetic variation for both species within and between the five collection sites in order to detect population substructuring. Nucleotide substitutions and insertion/deletion polymorphisms (indels) resulted in 35 P. costatus haplotypes (sample size = 89) and 22 P. argenteus haplotypes (sample size = 32). Significant genetic diversity and population differentiation was detected between five sampling sites for both species. Therefore, each of the five sites should be regarded as a group comprising significant genetic differences in species conservation and maintenance plans. Comparing these results to genetic diversity measures after dam construction will be critical for future management in this region.

Apoptosis, cell proliferation and vitellogenesis during the folliculogenesis and follicular growth in teleost fish

Aiming to better understand folliculogenesis, this study evaluated cell death and proliferation of ovarian cells, besides cathepsin-D expression in Prochilodus argenteus captured in two sites of the São Francisco River downstream from the Três Marias Dam, Brazil. In the site immediately following the Dam (S1), low levels of dissolved oxygen were registered in the rainy period. The water temperature was higher in the São Francisco River immediately after the confluence with the Abaeté River (S2), regardless of the period. In S1, the ovaries showed smaller oocytes, high caspase-3 enzymatic activity and apoptosis, lower cells in proliferation and GSI, as well as a lesser quantity of cathepsin-D when compared to females captured from S2. Regarding relative frequency of ovarian structures, in the dry period, only oogonia and perinucleolar oocytes were found in fish ovaries from both sites. On the other hand, in the rainy period, the relative frequency of oogonia and perinucleolar oocytes decreased and the vitellogenic oocytes increased in S2. Postovulatory follicles were observed only in S2, whereas atretic follicles occurred at a higher frequency in S1. Our results showed that apoptosis, cell proliferation and cathepsina-D evaluation can be used as biomarkers of environmental impact.

Functional dissimilarity of melanomacrophage centres in the liver and spleen from females of the teleost fish Prochilodus argenteus

Melanomacrophage centres (MMCs) are formed by macrophage aggregates containing pigments such as hemosiderin, melanin and lipofuscin. MMCs are found in animals such as reptiles, amphibians and, mainly, fishes, in organs such as the kidney, spleen, thymus and liver. In teleost fish, several functions have been attributed to MMCs, including the capture and storage of cations, the phagocytosis of cellular debris and immunological reactions. As the use of MMCs has been suggested as a tool for the assessment of environmental impacts, our aim has been to describe the various metabolic processes performed by MMCs in diverse organs (liver and spleen) by using the teleost Prochilodus argenteus as an animal model. MMCs from the liver and spleen were assessed by histochemistry, transmission electron microscopy, scanning electron microscopy, X-ray microanalysis techniques and biochemical assay for N-acetylglucosaminidase activity. The data showed metabolic differences in MMCs between the liver and spleen of P. argenteus in their morphometric characteristics and biochemical and elemental composition. The implications of these findings are discussed, focusing on their role in organ metabolism.

Influence of water temperature on induced reproduction by hypophysation, sex steroids concentrations and final oocyte maturation of the “curimatã-pacu”Prochilodus argenteus (Pisces: Prochilodontidae)

Most fishes with commercial importance from the São Francisco basin are migratory and do not complete the reproductive cycle in lentic environments, such as hydroelectric plant reservoirs, hence natural stocks are declining and there is an urgent need to reduce the pressure of fishing on those wild populations. Therefore, studies on reproductive biology and its relationship with endocrine and environmental factors are key to improving the cultivation techniques of Brazilian fish species. This study examined the influence of water temperature on sex steroid concentrations (testosterone, 17β-estradiol and 17α-hydroxyprogesterone), spawning efficiency, fecundity, fertilisation rate, larval abnormality rates and involvement of the cytoskeleton during the final oocyte maturation of Prochilodus argenteus under experimental conditions. The results of our study showed that in captivity, sex steroid plasma concentrations and spawning performance of P. argenteus were clearly different for fish kept in water with different temperature regimes. In lower water temperature (23°C), it was observed that: 33% of females did not ovulate, fecundity was lower and vitellogenic oocytes after the spawning induction procedure exhibited a smaller diameter. Moreover, concentrations of 17β-estradiol and 17α-hydroxyprogesterone were lower and there was a delay in the final oocyte maturation and, consequently, ovulation and spawning. Our experiments showed direct influence of water temperature in the process of induced spawning of P. argenteus. Changes in water temperature also suggest the tubulin involvement in the nuclear dislocation process and the possible action of actin filaments in the release of polar bodies during final oocyte maturation of P. argenteus.

Hematological characteristics, frequency of micronuclei and nuclear abnormalities in peripheral of fish from São Francisco river Basin, Minas Gerais State, Brazil

This study aimed to determine the variables leukocytary, erythrocytary, frequency of micronuclei and nuclear abnormalities in peripheral erythrocytes of Prochilodus argenteus, Pimelodus maculates and Myleus micans from São Francisco river basin, Minas Gerais State, during the summer and winter. Thrombocytes, hematocrit and leukocyte of P.argenteus series, was influenced by climatic conditions. In P. maculatus, not were significant differences for all leukocytes and thrombocytes. In M. micans, values are unprecedented in the literature, with MCV and absolute number of leukocytes found superior to other species of the family Characidae. The frequency of micronuclei and nuclear abnormalities in erythrocytes, the three species not showed seasonal differences between the sites. However, the highest values were found in summer. Furthermore, we observed a positive correlation between the increase in the percentage of micronuclei with nuclear abnormalities.

Collapse of the reproductive process of two migratory fish (Prochilodus argenteus and Prochilodus costatus) in the Três Marias Reservoir, São Francisco River, Brazil

Summary Generally, migratory fish can complete vitellogenesis even when the migration process is interrupted; however, final oocyte maturation does not occur and therefore there is no spawning. To evaluate the reproductive process of migratory fish inside the reservoir of the Tres Marias Dam (a lentic environment), 90 female and 81 male Prochilodus argenteus and 172 female and 115 male Prochilodus costatus were captured in this environment. Males and females from both species in the resting stage were pre-dominant, and the highest frequency of specimens in advanced maturation stages occurred in November, December and January. According to histological analysis, ovarian regression was frequent and vitellogenic oocytes undergoing atresia were intensely observed, moreover, no fish with ovaries and testes with characteristics of spawning and spermiation, respectively, were captured. This indicated that both species were preparing for reproduction and reaching advanced gonad maturation, but were unable to complete the process of reproduction in this environment. The data from this study indicate that the modification of portions of rivers to lentic environments can have a negative impact on the reproductive process of migratory fish in freshwater.

Habitat selection and maturation of Saccocoelioides nanii (Digenea: Haploporidae) in Prochilodus argenteus (Actinopterygii: Prochilodontidae) from the São Francisco River, Brazil

This work examined the possible preference of Saccocoelioides nanii Szidat, 1954 for the three major intestinal portions of Prochilodus argenteus Agassiz, 1829 and statistically evaluated whether the river water level dynamic interfered in the parasite's ecological parameters and in its transmission to the definitive host. One-hundred-fifty specimens of P. argenteus were collected in July, 2003 (dry season) and in January, 2004 (rainy season) in the upper São Francisco River, State of Minas Gerais, Brazil. Of the 150 hosts, 96 (64%) were parasitized by S. nanii. The mean intensity and abundance were 32.6 ± 34.8 and 20.8 ± 31.9, respectively, and the range of infection intensity was from 1 to 177. The abundance of S. nanii was higher in the middle intestine than in either the anterior or posterior portions. This selection could be evidence of niche restriction to facilitate mating. The proportion of non-pregnant specimens of S. nanii was higher in the dry season as well as the intensity and abundance. At least two hypotheses can be considered for elucidated this inference: the presence/absence or change in the quantity of some substance in the host body amending/inhibits the reproduction of the parasite or that non-pregnant specimens corresponds to newly recruited individuals who did not have time to reproduce.

Myxobolus franciscoi sp. nov. (Myxozoa: Myxosporea: Myxobolidae), a parasite of Prochilodus argenteus (Actinopterygii: Prochilodontidae) from the Upper São Francisco River, Brazil, with a revision of Myxobolus spp. from South America

Myxobolus franciscoi sp. nov. (Myxozoa: Myxosporea: Myxobolidae) is described from the curimata-pacu fish, Prochilodus argenteus Spix & Agassiz, 1829 (Actinopterygii: Prochilodontidae) from the Upper Sao Francisco River, Brazil. This parasite forms whitish plasmodia (about 1 x 1 mm) that develop in the connective tissue of fins. The spores are more or less round in frontal view and ellipsoidal in lateral view, measuring 6.4 (6.0-6.9) µm in length, by 6.0 (5.8-6.4) µm in width and 3.2 µm in thickness. The polar capsules are very small, measuring about 2 µm in length by 1.5 µm in width and ending in a tapered anterior neck. The polar filament makes three turns in a plane at right angles with the longitudinal axis of the spore. Thorough comparisons with the remaining species of Myxobolus Butschli, 1882 described from South American fish, as well as with almost all species of Myxobolus described so far, are provided. This paper also includes a revision of Myxobolus species from South American fish hosts.

Ecological parameters of the endohelminths in relation to size and sex of Prochilodus argenteus (Actinopterygii: Prochilodontidae) from the Upper São Francisco River, Minas Gerais, Brazil

This research aimed to investigate the ecological indexes of the helminths of the digestive system and coelom of Prochilodus argenteus Spix & Agassiz, 1829. A total of 150 specimens (53 males and 97 females) taken from the upper reaches of the Sao Francisco River in the municipality of Tres Marias (18o12'32S, 45o15'41W), State of Minas Gerais, Brazil, were examined. The specimens were collected in July, 2003 and January, 2004. Ninety-eight fish (65.3%) were infected by at least one species of helminth. Five helminth species were found: one digenean, Saccocoelioides nanii Szidat, 1954; two Eucestoda, Valipora sp., and one undetermined metacestode; one nematode, Spinitectus asperus Travassos, Artigas & Pereira, 1928; and one acanthocephalan, Neoechinorhynchus prochilodorum Nickol & Thatcher, 1971. The sex of the host did not influence parasite indexes. The total length of the hosts influenced the abundance of S. nanii (rs = -0.21, p = 0.01) and the prevalence of the metacestode (r = -0.91, p = 0.01). Saccocoelioides nanii was the dominant species in the parasite fauna of P. argenteus. Saccocoelioides nanii, Valipora sp., S. asperus and N. prochilodorum are reported here for the first time in P. argenteus and their known distribution is expanded to the Sao Francisco River.

Estrutura da assembléia de peixes de uma lagoa marginal desconectada do rio, no submédio Rio São Francisco, Pernambuco

Foram realizadas coletas utilizando vários apetrechos de pesca, entre os meses de março/07 e fevereiro/08, na lagoa Curralinho, uma lagoa marginal no trecho submédio do rio São Francisco, com o objetivo de avaliar a composição ictiofaunística após seu isolamento da calha principal do rio e deplecionamento de água. Foi coletado um total de 4.638 espécimes, com uma biomassa de 129.782,84 g, distribuídos em 16 famílias e 47 espécies das ordens Characiformes, Cyprinodontiformes, Siluriformes, Perciformes, Gymnotiformes e Clupeiformes. Observou-se que os Characiformes foram os mais abundantes, com 87,3% dos exemplares de pequeno (<100 mm) e médio porte (<200 mm). Dentre as espécies encontradas, 26,7% são constantes, 35,6% acessórias e 37,8% acidentais. Characidae concentra a maioria das espécies e indivíduos, seguida de Acestrorhynchidae. Moenkhausia costae, Triportheus guentheri, Pygocentrus piraya e Prochilodus argenteus apresentaram constância de 100%. Invertívoros e piscívoros dominaram quantitativamente e sua biomassa indica um domínio de predadores, tendo os detritívoros apresentado a segunda maior biomassa. Houve uma predominância de espécies sedentárias, com poucos exemplares de espécies migradoras, das famílias Anostomidae e Prochilodontidae e Salminus franciscanus. A riqueza, diversidade e eqüitabilidade apresentaram-se relativamente altas durante todo o período de estudo. Pode-se concluir que a lagoa Curralinho é um importante ambiente de abrigo, alimentação e descanso para a ictiofauna, mantendo peixes forrageiros que servem de base para a cadeia trófica e a sustentação pesqueira. Em vista disso, faz-se necessário o desenvolvimento de políticas ambientais e práticas de manejo que preservem a integridade desses habitats e a funcionalidade de seu papel na conservação da ictiodiversidade deste trecho da bacia do São Francisco.

Profiles of sex steroids, fecundity, and spawning of the curimatã-pacu Prochilodus argenteus in the São Francisco River, downstream from the Três Marias Dam, Southeastern Brazil

The present study evaluated for the first time sex steroid profiles and fecundity in females of Prochilodus argenteus from two sections of the São Francisco River Brazil, downstream from the Três Marias Dam, which influences characteristics of their water habitat. The model species in the study, P. argenteus, is an important commercial and recreational species in Brazil. In the region closest to the dam (section 1), females did not reach final oocyte maturation, failed to spawn, and displayed lesser circulating concentrations of testosterone, 17(-hydroxyprogesterone (17(-P) and 17β-estradiol (E2) than those farther downstream of the dam (section 2). The endocrine and fecundity deficiencies probably are attributed to lower water temperature and oxygen concentration in (section 1). The follicular atresia rate in the region closest to the dam (26%) was greater than those fish captured farther downstream of the dam (13%), after the Abaeté River (section 2). Variations in testosterone, E2 and 17(-P concentrations in section 2, followed gonadal maturation which are typical features of species which have seasonal reproduction, group-synchronous oocyte development, and are single batch spawners such as P. argenteus. Results document the first evidence of endocrine and reproductive dysfunctions caused by inadequate water conditions in a wild population of the migratory species P. argenteus in the São Francisco River, downstream from the Três Marias dam.

Ovarian follicular atresia is mediated by heterophagy, autophagy, and apoptosis in Prochilodus argenteus and Leporinus taeniatus (Teleostei: Characiformes)

We investigated apoptosis, cell proliferation antigen (PCNA), and heat shock protein (HSP70) during ovarian follicular atresia in two freshwater teleost species from the São Francisco River basin, Brazil: curimatã-pacu, Prochilodus argenteus and piau-jejo, Leporinus taeniatus. Fishes were maintained in captivity after the reproductive period and ovarian regression was assessed by gonadosomatic index for three stages: early, advanced, and late regression. Follicular atresia was analysed by light and transmission electron microscopy, as well as by TUNEL and immunohistochemistry for HSP70 and PCNA. During early regression, atretic follicles exhibited zona pellucida breakdown, yolk degeneration, and hypertrophied follicular cells (e.g. granulosa in mammals). Intense heterophagy to engulf the yolk, and autophagy were detected in the follicular cells during advanced and late atresia. The TUNEL assay detected DNA fragmentation, mainly in late follicular atresia. The apoptosis rate of the follicular cells increased up to 10% during follicular atresia in both species and was negatively correlated with follicular area. Immunohistochemistry reaction for HSP70 stained the follicular cells strongly during advanced atresia, when they are intensively involved in yolk engulfment, whereas the reaction for PCNA labelled theca cells. We inferred that heterophagy, autophagy, and apoptosis contributed to follicular atresia in teleost ovaries, thereby achieving a more efficient removal of the degenerating oocyte and dying follicular cells. Additionally, HSP70 may protect the follicular cells before apoptosis when they are involved in yolk engulfment, and cell proliferation in the theca contributed to ovarian remodelling.

Relationship among follicular apoptosis, integrin β1 and collagen type IV during early ovarian regression in the teleost Prochilodus argenteus after induced spawning

Early ovarian regression was analyzed in the neotropical freshwater teleost, curimatã-pacu (Prochilodus argenteus), in order to evaluate follicular apoptosis, basement membrane morphology, and integrin beta1 and collagen type IV immunostainning in postovulatory follicles. Mature females were induced to spawn by using carp pituitary extract for study of ovarian regression up to 5 days post-spawning. Morphometric analyses showed that the postovulatory follicle area decreased progressively after spawning and was coupled to the gonadosomatic index (r=0.92). During ovarian regression, follicular cells detached from the neighboring cells and basement membrane and then died by apoptosis. The follicular basement membrane became thicker and diffuse and was breached during regression of the postovulatory follicles. Follicular apoptosis was detected by TUNEL, histology, and electron microscopy. The ladder pattern of apoptotic DNA was revealed by agarose gel electrophoresis. The apoptotic index for the follicular cells increased until 3 days post-spawning and decreased thereafter. Immunohistochemistry reactions detected caspase 3, integrin beta1, and collagen type IV in the follicular layer of the postovulatory follicles. Labeling for integrin beta1 and collagen type IV decreased significantly, whereas a peak in cell death occurred 3 days post-spawning. At 4-5 days post-spawning, the connective theca was more thickened and vascularized. Simultaneously, granulocytes migrated toward the follicular lumen. Thus, follicular apoptosis contributes to early ovarian regression in P. argenteus. Additionally, our findings suggest integrin beta1 and collagen type IV as possible survival factors for follicular cells in teleost ovary.

Description of novel microsatellite loci in the Neotropical fish Prochilodus argenteus and cross-amplification in P. costatus and P. lineatus

Prochilodus is one of the most important fish resources of South America, in addition to the important role it plays in nutrient cycling of Neotropical rivers. In the present study, we describe the isolation and characterization of nine novel microsatellite loci in Prochilodus argenteus. The number of alleles per polymorphic locus varied from 5 (Par76) to 21 (Par85), revealing a total of 116 alleles. The values of observed and expected heterozygosities ranged from 0.629 (Par69) to 0.926 (Par85 and Par86) and from 0.643 (Par66) to 0.931 (Par80), respectively. Furthermore, the ability of these and other previously described microsatellite markers to amplify orthologous loci was tested in two related species, Prochilodus costatus and Prochilodus lineatus. These loci will be useful for studies of population genetic structure in this group of fishes, and in aiding future genetic mapping studies of P. argenteus.

Diversity of fish and fisheries from the Lake Encantada Environmental Protection Area, Ilhéus, Brazil

Abstract Lake Encantada, in the basin of the Almada River (Bahia State), has an area of 650.5 ha and a perimeter of 13.3 km. In 1993, an area of 11 800 ha around the lake was designated an Environmental Protection Area (Class V category). The main goal of this study was to identify fish species in the lake and to determine possible threats to their conservation. Fish samples were obtained with gillnets between May 2002 and February 2004, and used to calculate indices of species diversity Shannon (H′), richness (d) and evenness (J′). Eleven fish species comprising nine families were collected during the sampling period. Three introduced species occurred in the lake: Prochilodus argenteus, endemic to the São Francisco river basin, and two African species, Oreochromis niloticus and Clarias gariepinus. In overall ranking, Prochilodus argenteus was first in number of individuals (46%) and weight (59%), followed by Genidens genidens in numbers (31%), and Clarias gariepinus in weight (15%). The occurrence and dominance of introduced species is discussed as well as their possible impacts on the trophic structure of this ecosystem. Copyright © 2007 John Wiley & Sons, Ltd.

Influência da biomassa inicial sobre o crescimento e a produtividade de peixes em sistema de policultivo

Analisou-se o crescimento dos peixes, a composição das espécies e a produtividade de quatro policultivos (P75, P78, P87 e P207), visando melhorar o manejo e a produtividade pesqueira dos pequenos açudes (0,1-5,0ha) do Semi-Árido brasileiro. Simulou-se as condições desses açudes em viveiros com 120 e 5.000 m² de área, sem renovação de água, utilizando moderada quantidade de adubo e fertilizante. A biomassa inicial variou de 75 a 207kg ha-1, sendo formada por: tilápia do Nilo (Oreochromis niloticus), curimatã pacu (Prochilodus argenteus), carpa comum (Cyprinus carpio), tambaqui (Colossoma macropomum) e tucunaré (Cichla ocellaris). Os peixes apresentaram baixo crescimento (< 0,01g g-1 d-1) após 75 dias de criação (P78 e 87). O crescimento do tambaqui, da tilápia e da curimatã foi reduzido após 53 dias (P75). Em moderada biomassa, o crescimento do tambaqui foi inferior ao da carpa e da curimatã (P207). A produtividade da tilápia atingiu 720 kg ha-1ano-1 (P78), sendo reduzida para 220 kg ha-1ano-1 devido ao processo reprodutivo (P75 e P207). A produtividade da carpa de 1.600 kg ha-1ano-1 foi superior a dos outros peixes (P87). A biomassa inicial de 75 kg ha-1 (60:30:4:3:3% de tilápia, tambaqui, carpa, curimatã e tucunaré, respectivamente) otimizou o crescimento e a produtividade dos peixes. A utilização de tilápias monossexadas e o fornecimento da alimentação suplementar ao tambaqui tornam-se imprescindíveis ao policultivo.

Thirteen polymorphic microsatellite loci in the Neotropical fish Prochilodus argenteus (Characiformes, Prochilodontidae)

Abstract Prochilodus species inhabit the main river systems of South America and usually present commercial value to inland fishing. In the present study, we describe the isolation and characterization of 13 novel microsatellite loci in Prochilodus argenteus. The number of alleles per polymorphic locus varied from four to 22 and the observed heterozygosity ranged from 0.333 to 0.893. Additionally, cross‐species amplification was successful in two other Prochilodus species. These loci will be useful for studies of the population genetic structure in this fish group.

Migration and Spawning of Radio‐Tagged Zulega Prochilodus argenteus in a Dammed Brazilian River

AbstractIt is difficult for agencies to evaluate the impacts of the many planned dams on São Francisco River, Brazil, migratory fishes because fish migrations are poorly known. We conducted a study on zulega Prochilodus argenteus, an important commercial and recreational fish in the São Francisco River, to identify migrations and spawning areas and to determine linear home range. During two spawning seasons (2001–2003), we radio‐tagged fish in three main‐stem reaches downstream of Três Marias Dam (TMD), located at river kilometer (rkm) 2,109. We tagged 10 fish at Três Marias (TM), which is 5 km downstream of TMD; 12 fish at Pontal, which is 28 km downstream of TMD and which includes the mouth of the Abaeté River; and 10 fish at Cilga, which is 45 km downstream of TMD. Late‐stage (ripe) adults tagged in each area during the spawning season remained at or near the tagging site, except for four Cilga fish that went to Pontal and probably spawned. The Pontal area at the Abaeté River mouth was the most important spawning site we found. Prespawning fish moved back and forth between main‐stem staging areas upstream of the Abaeté River mouth and Pontal for short visits. These multiple visits were probably needed as ripe fish waited for spawning cues from a flooding Abaeté River. Some fish homed to prespawning staging areas, spawning areas, and nonspawning areas. The migratory style of zulega was dualistic, with resident and migratory fish. Total linear home range was also dualistic, with small (<26‐km) and large (53–127‐km) ranges. The locations of spawning areas and home ranges suggest that the Pontal group (which includes Cilga fish) is one population that occupies about 110 km. The Pontal population overlaps a short distance with a population located downstream of Cilga. Movements of late‐stage TM adults suggest that the TM group is a separate population, possibly with connections to populations upstream of TMD.