Swimming Legs Research Articles

A new species of Thermocyclops Kiefer, 1927 (Crustacea, Copepoda, Cyclopoida, Cyclopidae) from temporary habitats, with a discussion on the diversity and distribution of the genus in Thailand

Thermocyclops Kiefer, 1927, is a genus of Cyclopidae, one of the most diverse families among cyclopoids. To date, 13 species of this genus have been recorded in Thailand. Through intensive sampling of rice fields in central Thailand and temporary waters in northeastern Thailand, one new species, Thermocyclops oryzaesp. nov., was discovered. This new species is clearly distinguished from other Thermocyclops by the presence of a serrated lobe on the posterior surface of the medial expansion of the basipodite of the fourth swimming leg. Moreover, it can be distinguished from its congeners by (i) ornamentation on the genital double-somite, succeeding two urosomites and caudal ramus; (ii) the length and width ratio of the caudal ramus; (iii) the length ratio of the innermost terminal seta (VI) and the outermost terminal seta (III); (iv) the number of setae on the second endopodal segment of the antenna; (v) projection and ornamentation on the intercoxal sclerites of the first to fourth swimming legs; (vi) the surface ornamentation of the medial margin of the basipodite of the first to fourth swimming legs; and (vii) the relative length of two apical spines of the third endopodal segment of the fourth swimming leg. The present discovery increases the number of species in this genus in Thailand to 14. A pictorial key to all species is proposed, and their ecologies and distributions within Thailand are updated and discussed.

Kinematic characteristics of calanoid copepod appendage motion

Abstract Propulsion by copepods requires high-speed video and intensive analyses. Routine smooth swimming is compared with small relocation jumps and escape reactions, relying on kinematics analyses of appendage movement. In this study, we used high-speed video at 1200 frames per second to determine the kinematic parameters of three types of swimming in Eurytemora affinis females: routine steady swimming, small relocation jumps and escape reactions. The average speed varied in the range 0.30–0.82 cm s−1 during steady routine swimming. This value increased to 4.48 ± 1.01 cm s−1 during small relocation jumps, and reached 21.94 ± 2.68 cm s−1 during escape reactions. The small angular amplitude (40–50°) and the very high beat frequency (63–80 Hz) of the cephalic appendages during routine swimming indicate that E. affinis is a feeding-current feeder. The comparison of the angular displacements of the antennules, thoracic legs and abdomen with respect to the movement speed demonstrates that, both in the case of small relocation jumps and during escape reactions, the main propulsive role is played by the thoracic swimming legs and abdomen.

Race Dynamics in Triathlon Mixed-Team-Relay Meaningfully Changes with The New Regulation Towards Paris 2024.

Mixed-Team-Relay (MTR) triathlon is a novel Olympic discipline whose performance determinants and tactical behaviors have barely been studied. Additionally, a regulatory change has been made to the male and female relay order for the Paris 2024 Olympics. Therefore, this study aimed to determine the performance determinants and race dynamics as a function of competitive level on the new regulated MTR triathlon. Results from 129 national teams, (516 elite triathletes) across five MTR World Triathlon Series and two MTR European Championships in 2022 and 2023, were analyzed. Split times, average speeds, time behind the race leader (gap), partial and finishing positions, pack position as well as the rank positions of every segment, relay leg, and overall race were computed. Decision tree analyses were conducted as a predictive method for the overall results, and correspondence analyses were conducted to examine the relationship between the different relay legs and segments and the finishing positions. The performance of the fourth leg was the most relevant for overall result (30%), as well as the fourth running leg (16%) and the female legs performance (7%). Medallist relay teams were characterized by displaying a differential speed lower than 0.5 and 0.83 km/h, respectively, from the best-ranking athletes in the Legs 1 and 4. Furthermore, staying in the front pack after the second swimming leg showed a great relationship with achieving a medal position. New MTR triathlon rules shift race dynamics, emphasizing individual efforts in cycling and swimming, while maintaining the crucial importance of running.

Moulting Performances Evaluation of Female Orange Mud Crab, Scylla olivacea (Herbst, 1796) In-Captivity: Effects of Water Salinity and Limb Autotomy.

Female Scylla olivacea has become more popular in Malaysia as emerging species mainly for soft-shell crabs and crab fattening (to increase weight, size and ovary maturation so that they can be sold at a higher price). To harvest crabs in soft-shell conditions and fattening, both conditions depend mostly on moulting events. To accelerate the moulting process, the manipulation of water parameter (salinity) and autotomy of the limb is commonly used. In this study, the evaluation of the moulting performances of full limb autotomy (the removal of all the appendages except for the swimming legs) and non-ablated (control) using immature S. olivacea cultured in three different salinity treatments (10 ppt, 20 ppt and 30 ppt) were performed. Results indicate there were significant differences between mud crab's culture duration, BW increments, growth performances and feeding efficiency with salinity. However, CW increments and survival indicate no significant effect with salinity. Meanwhile, limb autotomy proved to affect the culture duration, BW increments, survival and feeding efficiency of S. olivacea. The study concludes that both salinity and limb autotomy play significant roles in moulting performances of S. olivacea, with 20 ppt being the best salinity to stimulate S. olivacea moulting and development compared with the other two treatments (10 ppt and 30 ppt). Limb autotomy also indicates promising results as this technique proved to accelerate the moulting duration of S. olivacea with a 100% moulting percentage within 30 days. Therefore, the outcome would certainly benefit in the aquaculture production of this species of commercial importance mainly on soft-shell crabs production and also emerge as crabs fattening technique.

A New Species of Diacyclops (Copepoda, Cyclopoida) from the D. crassicaudis (Sars, 1863) Species Group with Critical Taxonomy Remarks

A new species, Diacyclops dyabdar sp. nov. from the Diacyclops crassicaudis (Sars, 1863) species group from northern Middle Siberia, is described. This species is interesting from an ecological point of view, as it lives mainly in watercourses. It is well-distinguished from other species of the group by the presence of spinules on the first segments of the third and fourth pairs of swimming legs, details of the ornamentation on the fourth pair of legs and caudal rami. A detailed comparison of the new species and D. crassicaudis is presented. Molecular markers, including cytochrome c oxidase (COI) of mtDNA and 18S rRNA, ITS1 and ITS2 of nuclear DNA were obtained for a single female of D. dyabdar sp. nov. A morphometric analysis of species and subspecies of the D. crassicaudis group was carried out. It showed slight differences between the described subspecies and some species. On this basis, the subspecies D. crassicaudis, as well as D. iranicus Pesce & Maggi, 1982 and D. fontinalis Naidenow, 1969, are synonymized with the subspecies type. A more precise diagnosis of the D. crassicaudis group is indicated. This group now includes six species. The taxonomic position of several questionable taxa of Diacyclops Kiefer, 1927 described from Iran is discussed: D. landei Mahoon & Zia, 1985; D. bicuspidatus jurenei Najam-un-Nisa, Mahoon & Irfan Khan, 1987; D. landei richardi Parveen, Mahoon & Saleem, 1988 and D. jurenei Parveen, Mahoon & Saleem, 1988. These taxa are accepted as nomen dubium.

Two New Species of Elaphoidella (Copepoda, Harpacticoida) from Subterranean Waters in Northeast Thailand, with a Record of a Gynandromorphic Specimen and an Up-to-Date Key to Elaphoidella Species from Southeast Asia

Two new species of copepods of the genus Elaphoidella Chappuis, 1929 were discovered in a cave and a spring in northeastern Thailand. The first species, E. phuphamanensis sp. nov., belongs to species-group VII sensu Lang. It is most similar to E. turgisetosa Petkovski, 1980 in the armament of the male third exopod of the fourth swimming leg and the shape and armament of the fifth swimming leg in both sexes. However, it is easily distinguished from other congeners by the segmentation of the first swimming leg, the endopod of the fourth swimming leg, and the armature of the third exopod of swimming legs 2–4 in both sexes. The second species, E. propecabezasi sp. nov., is located in species-group I sensu Lang, where the male does not have a transformed seta on the third exopod of the fourth swimming leg and the female fifth swimming leg has four baseoendopodal robust setae, unequal in length. It is most similar to E. cabezasi Petkovski, 1982 and E. paraaffinis Watiroyram, Sanoamuang and Brancelj, 2017 in having the same armature formula as endopods 1–2 of female swimming legs 1–4. However, the ornamentation of the anal operculum, the shape of the caudal ramus, and the armature of the fifth swimming leg in both sexes distinguish them from each other. A rare gynandromorphic specimen of E. propecabezasi sp. nov. was recorded, and a revised key to Elaphoidella species in Southeast Asia is provided.

Intensity and prevalence of ectoparasites in whiteleg shrimp Litopenaeus vannamei and mud crab Scylla serrata harvested from Aceh waters Indonesia

Ectoparasite infections are a common problem in small-scale aquaculture, exerting a substantial influence on fishery production. In the context of Indonesia, the two prevalent fishery commodities are whiteleg shrimp Litopenaeus vannameii and mud crab Scylla serrata. These species are extensively cultured within Aceh province, using traditional and semi-intensive aquaculture ponds and there are no reports on ectoparasites in these two species of crustaceans. Therefore, this study aimed to analyze the intensity and prevalence of ectoparasites in mud crab and whiteleg shrimp from Aceh between August to December 2022. Mud crab samples were collected from three locations, namely Langsa City, East Aceh, and North Aceh districts, while whiteleg shrimp samples were sampled from coastal ponds in Banda Aceh, Aceh Besar, and Aceh Jaya districts. The samples were collected over five months, and a total of 300 for each species were examined microscopically by scraping the swimming legs body, and gills. Furthermore, macroscopic-sized and microscopic-sized ectoparasites were observed using stereo and binocular microscopes, respectively. The results showed that five species of ectoparasites were recorded during the study, namely Octolasmis sp., Vorticella sp., Epistylis sp., Oodinium sp., and Zoothamnium sp. Mud crab exhibited infestations of Octolasmis sp., Vorticella sp., Epistylis sp., and Oodinium sp., while whiteleg shrimp were infested by Vorticella sp., Epistylis sp., and Oodinium sp. In this study, the highest intensity for crab and shrimp was recorded in Octolasmis sp. and Epistylis sp., in November and September, respectively. The gills showed higher intensity compared to other infested organs and based on sample origin, crab and shrimp from Langsa and Banda Aceh Cities had higher results compared to other locations. The prevalence of ectoparasites exhibited a high value, reaching 100%, showing that crustacean samples were infested by ectoparasites. Therefore, the intensity of ectoparasite was varied according to sample of origin, time of sampling and infested organs. The samples of both crab and whiteleg shrimp from all locations consistently exhibited ectoparasite infestations throughout the entire study period.Keywords:Octolasmis sp.Vorticella sp.Epistylis sp.Oodinium sp.Zoothamnium sp.

New species of Dermoergasilus Ho & Do, 1982 (Copepoda: Cyclopoida: Ergasilidae) parasitizing endemic cichlid Paretroplus polyactis (Bleeker) in Madagascar.

Dermoergasilus madagascarensis n. sp. is described from the gills of Paretroplus polyactis, an endemic cichlid fish in Madagascar, using a combined morphological (light microscopy and SEM) and molecular approach (partial 18S rDNA, 28S rDNA, and COI sequences). The new species is characterized mainly by possessing: (i) roughly pentagonal cephalosome; (ii) antennal endopodal segments covered with slightly inflated membrane; (iii) maxillule bearing 2 equally long outer setae and a minute inner seta; (iv) interpodal sternites of swimming legs ornamented with 3–4 rows of spinules; (v) genital segment and first abdominal somite both barrel-shaped; and (vi) a caudal ramus projecting into a digitiform process with inconspicuous terminal seta and bearing 3 terminal setae. The obtained DNA sequences of Malagasy species represent the first molecular data for species of Dermoergasilus. The 28S rDNA phylogeny showed the affiliation of D. madagascarensis n. sp. to Ergasilidae and its sister relationship with cosmopolitan Ergasilus sieboldi von Nordmann, 1832. The first checklist for all species of Dermoergasilus is provided.

The detection of three species complexes similar to Diacyclops galbinus, D. versutus and D. improcerus (Copepoda: Cyclopoida) from Lake Baikal

Cyclopoids are an extremely diverse and abundant group of arthropods found in Lake Baikal. Diacyclops Kiefer, 1927 is the most species-rich and highly endemic genus among them. The morphological characteristics of the three Baikal species, D. improcerus, D. galbinus and D. versutus, show considerable differences. Therefore, it is worth considering whether all specimens identified as versutus, galbinus, or improcerus belong to the same species. Molecular and morphological analyzes were conducted on Diacyclops from Lake Baikal, which are similar to D. improcerus, D. galbinus and D. versutus. Three molecular markers of mtDNA (COI, 12S) and nuclear DNA (ITS1) revealed three clusters corresponding to the division of specimens into three groups based on morphological characteristics. Each of these groups comprises multiple genetic lineages. We assume that the improcerus-, galbinus-, and versutus- groups are closely related species complexes. The use of PCA for morphometric indices based on linear measurements, which are widely used in Cyclopoida taxonomy, is limited in separating closely related species within species complexes. Micrographs and line drawings of a fourth swimming leg (P4) and an antenna from specimens of the versutus- and improcerus- groups are provided. These images reveal significant differences in the spinule ornamentation of the coxopodite of P4 and the basipodite of the antenna between specimens of different genetic lineages.

Troglophonte Huys & Lee, 2000 (Copepoda, Harpacticoida, Laophontidae) Cinsinin Değiştirilmiş Diyagnozu ve Yeni Bir Türünün Deskripsiyonu

A new species of the monotypic genus Troglophonte Huys & Lee, 2000 (Harpacticoida, Laophontidae) was discovered among the interstitial samples collected from the Kumada Coast in the Sea of Marmara. The new species can be distinguished from the type species T. spelaea (Chappuis, 1938) by the following characters: (i) female 6-segmented antennule, (ii) P3 exp terminal segment with 7 setae, (iii) female P5 exopodal lobe with 5 setae, (iv) female P5 baseoendopod with 3 setae on endopodal lobe, (v) surface ornamentation of swimming legs, (vi) male P5 baseoendopod distal seta ornamentation, and (vii) male P5 exopod setal ornamentation. The type material of T. spelaea does no longer exist and its diagnosis is concise. Therefore, the generic diagnosis has been updated to include the characters displayed by the new species. Additionally, a phylogenetic analysis including other genera related to the Troglophonte was conducted using parsimony. The results obtained from the phylogenetic analysis were generally consistent with the previous studies.

Does Pool Performance of Elite Triathletes Predict Open-Water Performance?

The capacity of laboratory tests to predict competition performance has been broadly researched across several endurance sports. The aim of the present study was to analyse how pool swimming performance can predict the result of the swimming segment in triathlon competitions and compare predictability differences based on competition level and distance. Eighteen male triathletes participated in the study. Three were ranked world-class, ten elite/international level, and five highly trained/national level. A total of sixty-one graded multi-stage swimming tests were conducted. Blood lactate was measured to calculate the following hypothetical predictor variables: speed at lactate threshold 1 (LT1), speed at lactate threshold 2 (LT2), and speed in the last repetition of the test (SL200). The following data were collected for a total of 75 races: time in the swimming leg (TSL); position after the swimming leg (PSL); time difference with the first triathlete after the swimming leg (DFT); and final race position. The race levels were divided according to participant levels as follows: world series (WS) (n = 22); World Cup (WC) (n = 22); Continental Cup (CC) (n = 19); national championship (N) (n = 5); and local race (L) (n = 5). Based on distance, they were divided into Olympic distance (OD) (n = 37) and sprint distance (SD) (n = 38). A moderate to strong positive association was found between LT1, LT2, SL200 and PSL and TSl at all race levels except for the SD CC, SD WC, and OD CC races, where no or weak-to-moderate correlations were found. The present study demonstrated that performance measured in a graded multi-stage pool lactate test can predict performance in a triathlon swimming segment. This finding is highly useful for coaches as it can help them to obtain a reliable measure of the triathlete's specific capabilities in the swimming leg.

Study of the population Vibrio Sp. on the health of vanname shrimp (Litopenaeus vannamei) in Cv. Reksa Bumi Situbondo

Vannamei shrimp is one of the commodities of excellence in aquaculture. The production system is carried out mass with high stocking density causes vannamei shrimp culture susceptible to disease. One type of disease that can cause mass mortality in cultured shrimp is vibriosis. This activity aims to study the abundance of bacterial populations Vibrio sp. and its effect on the health of Vanname Shrimp (Litopenaeus vannamei) at CV. Reksa Bumi Situbondo East Java. Identification of Vibrio sp. performed on TCBS agar media. Clinical symptoms of shrimp that are attacked by vibriosis. Besides the attack vibrio sp. produce clinical symptoms such as body flushing, red swimming legs and red tail. The abundance of Vibrio sp. that exceeds the threshold causes WFD disease attacks and IMNV. The high abundance of Vibrio sp. caused by conditions unfavorable aquatic environment due to entering the transition season resulting in sudden changes in water quality and increase the abundance of bacteria.

Prevalence and Intensity of Ectoparasites on Mud Crab (Scylla serrata) in Teluk Pakedai District, Kubu Raya Regency

Mud crabs (Scylla serrata Forskal, 1775) is a species of fishery commodity that can be attacked by pathogenic agents such as ectoparasites. Ectoparasites that infect mud crabs can trigger damage to the carapace and gills at a certain number of infections. This study aims to determine the prevalence and intensity of ectoparasites in mud crabs in Selat Remis Village, Teluk Pakedai District, Kubu Raya Regency. The study was conducted by taking random samples and determining the sample size based on the Lemeshow formula (95% confidence level), then to obtain prevalence and intensity it was carried out by examining the body organs (carapace, cheliped or (pereiopod I), pereiopods (walking legs), pereiopod V (swimming legs) and gills) of mud crabs (S. serrata) and identify the species of ectoparasites. Based on the results, the average prevalence of ectoparasites in mud crabs is 45,00% included in the commonly prevalence category. The prevalence value of each ectoparasites was Vorticella (17,50%), Zoothamnium (12,50%), Octolasmis cor (12,50%), Epistylis (15%), Octolasmis angulata (7,50%) and Acineta (2,50%). The highest intensity value of ectoparasites in mud crabs was O. angulata, 28 individuals per an infected mud crab.

The Influence of Adding Api-Api Mangrove Leaf Extract as an Immunostimulant on Vaname Shrimp Against Vibriosis Disease Caused by Vibrio parahaemolyticus Bacteria

Vanname shrimp cultivation is one of the most developed aquacultures in Indonesia and makes it one of the commodities with the highest foreign exchange inputs for the Indonesian state from the fisheries sector. Disease attack is one of the main causes of failure in vaname shrimp culture, especially disease attacks caused by Vibrio parahaemolyticus bacteria. Avicennia alba mangrove leaf extract is known to have active compounds that can act as antibacterial. This research was conducted by mixing Avicennia alba mangrove leaf extract with doses of 150 ppm (VA), 250 ppm (VB) and 350 ppm (VC) into commercial feed by re-pelletting. Positive control (KV+) treatment used commercial vitamins added to the feed. The vaname shrimp used was 60 days old with an average initial weight of 8.9 grams. The aquariums used were 15 pieces with a size of 60 x 30 x 40 cm and a volume of 54 liters of water. The white shrimp challenge test with Vibrio parahaemolyticus bacteria with a concentration of 106 Cfu/ml as much as 0.2 ml. The clinical symptoms of white vaname shrimp include pale white hepatopancreas, blackened tail, grippy swimming legs, necrosis in some parts of the body, necrosis of the tail, blackened and necrotic rectum, broken intestines that are partially brown and starting to turn white, empty intestines, presence of white feces. appears in the aquarium, decreased appetite, as well as not actively swimming. The results showed that Avicennia alba leaf extract had an effect on absolute weight growth (W), growth rate (GR), specific growth rate (SGR), survival rate (SR), total haemocyte count (THC) and phagocytic activity of white shrimp. The dose of 350 ppm VC treatment was the most influential dose as an immunostimulant in this study.

REDESCRIPTION OF <i>MORARIA</i> (<i>BAIKALOMORARIA</i>) <i>WERESTSCHAGINI</i> BORUTZKY 1949 (COPEPODA, HARPACTICOIDA, CANTHOCAMPTIDAE) FROM LAKE BAIKAL

This report is the second of a series devoted to redescriptions of members of Baikalomoraria based on modern research methods. An illustrated redescription of the female and male of Moraria (Baikalomoraria) werestschagini Borutzky 1949, a rare endemic harpacticoid species from the littoral zone of Lake Baikal, is presented. Since the type material of the species was lost, it became necessary to select a neotype. For the first time, the morphology of this species was studied in detail using scanning electron microscopy, and a description of the mouthparts and antennules was given. The description of the swimming legs was significantly supplemented and the structure of the genital field was shown, including data on the morphological variability of limbs. In addition, we briefly describe the fifth copepodite stages of the male and female. The fifth copepodite stage of the female was found to bear long apical setae on the caudal rami, vs adult females characterized by short setae more similar to spines.

Cletocamptus cubaensis n. sp. (Harpacticoida, Canthocamptidae) from Cuba with taxonomic notes on the species

Abstract A new species of harpacticoid copepod, Cletocamptus cubaensis n. sp., from a marine aquarium in Cuba, previously identified with the highly polymorphic Cletocamptus deitersi (Richard, 1897), is described herein. A revision of the Cuban material showed that, despite the morphological similarity to Cletocamptus deitersi, there are significant interspecific differences in several microcharacters that were not taken into account in the previous species determination, such as integumental sensilla and pores, and ornamentation of segments, mouthparts, swimming legs, prosome, and urosome. Additionally, some other differences were observed in the relative length and shape of the apophysis of the endopod of P3 in males, the armature complement of the second segment of endopod P2 in males (with four setae instead of three), the ornamentation and length of the caudal rami in both sexes, and the ornamentation of the anal operculum (with 8 spinules). Similarity to other species is discussed, along with brief comments on the morphological similarities and differences between the new species from Cuba and Cletocamptus nudus Gómez, 2005 recorded from Brazil and Colombia, C. schmidti Mielke, 2000 known from the Galapagos archipelago, and C. samariensis Fuentes-Reinés, Zoppi de Roa & Torres, 2015 from Colombia.

REDESCRIPTION OF <i>MORARIA</i> (<i>BAIKALOMORARIA</i>) <i>LONGICAUDA</i> BORUTZKY 1952 (COPEPODA, HARPACTICOIDA, CANTHOCAMPTIDAE) FROM LAKE BAIKAL

An illustrated redescription of the female and male of Moraria (Baikalomoraria) longicauda Borutzky 1952 is presented, a harpacticoid species endemic to the littoral zone of Lake Baikal, Siberia. A neotype is designated, because the type material is lost. The morphology of this species was studied in detail using scanning electron microscopy for the first time. An illustrated description of the mouthparts and antennules is given; that of the swimming legs being expanded. The structure of the genital field is shown and data on morphological variability are presented.

Establishment of a new subfamily of Idyanthidae Lang, 1944 with the description of a new species of Pseudometeorina George & Wiest, 2015 (Copepoda, Harpacticoida) from the Eratosthenes Seamount (eastern Mediterranean Sea)

The description of Pseudometeorina eratosthenica sp. nov. from the eastern Mediterranean Eratosthenes Seamount was the release for a detailed phylogenetic comparison of a group of derived representatives of the family Idyanthidae Lang, 1944, namely Aspinothorax Moura & Martínez Arbizu, 2003, Meteorina George, 2004, Pseudometeorina George & Wiest, 2015, and Styracothorax Huys,1993. The named genera share the derived presence of a 2-segmented P1 exopod as well as the transverse elongation of the bases of the swimming legs P1–P4, being these five deviations unique for Idyanthidae and therefore hypothesized here as synapomorphic for the above-named taxa. Consequently, they are pooled in the newly established Aspinothoracinae Moura & Martínez Arbizu, 2003 subfam. nov. The new species described from Eratosthenes Seamount doubtlessly belongs to Pseudometeorina, sharing with P. mystica George & Wiest, 2015, a set of 24 synapomorphies. Otherwise, P. eratosthenica sp. nov. provides nine autapomorphies that justify its establishment as distinct species. A detailed phylogenetic analysis, based on 131 morphological characters, is presented. Moreover, a key to the species of Aspinothoracinae subfam. nov. is provided.

Pengaruh Latihan Squats dan Lunges Terhadap Kekuatan Kaki Renang Gaya Dada 50 meter Pada Perenang Pemula Kelompok Umur 10 Tahun dan 12 Tahun di Club Marlin

This research was motivated by the concerns of researchers related to the lack of leg strength training in the 50 meter breaststroke swimming, the factors that affect the strength of the breaststroke swimming leg, and it is not known that squats and lunges exercises can increase the strength of the breaststroke swimming leg. The sampling technique in this study uses purposive sampling where the researcher determines the criteria regarding the respondents selected as the sample. Informants in this study were swimmers Club Marlin. The data collection technique in this study used a technique that was test. The analysis was carried out using a quantitative analysis model.
 The results of research conducted on the effect of squats and lunges on the strength of the legs in the 50-meter breaststroke for beginner swimmers aged 10 years and 12 years at Club Marlin showed that: there was a better effect between before and after being given treatment with squats and lunges exercises on increasing the strength of the legs in the 50-meter breaststroke for beginner swimmers in the 10-year age group and the effect of lunges exercise being more effective for increasing the strength of the 50-meter breaststroke for beginner swimmers in the 10-year & 12-year-old group at Club Marlin.

REDESCRIPTION OF <i>CANTHOCAMPTUS LATUS</i> BORUTZKY 1947 (COPEPODA, HARPACTICOIDA, CANTHOCAMPTIDAE) FROM LAKE BAIKAL

An illustrated redescription of both female and male of Canthocamptus latus Borutzky 1947, a mass endemic species of harpacticoid from the littoral zone of Lake Baikal, which plays important roles in the food chains of shallow waters, is given based on newly collected material. This species is well distinguished from other endemic Baikal species of the genus Canthocamptus Westwood 1836 in the structure of the caudal rami and swimming legs. Morphologically, the species is similar to Canthocamptus bulbifer Borutzky 1947. Information on the neotype is presented, because type material was lost. The morphology of this species was studied in detail using scanning electron microscopy for the first time. Illustrated descriptions of the mouthparts and antennules are given, and the description of the swimming legs is expanded. The structure of the genital field is shown, and data on morphological variability are presented.