Gyraulus parvus (Mollusca: Gastropoda) in the Czech Republic

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cestode was distinctly associated with the body size of the host, and both the prevalence and theintensity increased with increasing body size of fish. Because of the low rate of infection it was notpossible to quantify the seasonal changes in prevalence and mean intensity.Seasonal changes in maturation of Proteocephalus brooksiBecause of the rarity of P. brooksi in the intestine of catfish, it was impossible to make a detailedquantitative analysis of its state of maturity each month. The following specimens were found:June: 2 gravid specimens (body length about 4 cm), 4 nongravid specimens with mature segments(1.5–3 cm) and 10 immature specimens (1–1.5 cm); July: 1 immature specimen; August: 2 gravidFig. 8. Monthly changes in the occurrence and state of maturity of Rhabdochona kidderi Pearse in Rhamdiaguatemalensis (Günther) from the cenote Ixin-há over the period June to November 1994. The data are expressedas percentages of the total number of nematodes found per month: larvae and females without eggs (unsheaded),males (stippled), females with immature eggs in uteri (obliquely hatched) and gravid females with mature eggs inuteri (blackened).131
Tab. 6. Monthly survey of Rhamdia guatemalensis (Günther) from the cenote Ixin-há for infection with encapsulatedlarvae of Proteocephalus brooksi García-Prieto et al.month no. of fish examined no. of fish infected prevalence (%) intensity mean (range)June 20 9 45 30.0 (6–79)July 1 7 7 4 1 23.0 (1–45)August 14 6 43 21.0 (3–165)September 14 4 29 10.5 (4–22)October 15 7 47 32.7 (6–72)November 2 0 – –specimens, 2 nongravid specimens with mature segments and 5 immature specimens; September: 1larva (scolex) (length about 1 mm). This suggests that oviposition occurred in June and August,and new infections were acquired by fish from June to September.Occurrence of encapsulated Proteocephalus brooksi larvae in Rhamdia guatemalensisOut of 82 R. guatemalensis, 33 (prevalence 40%) had P. brooksi larvae encapsulated in theirmesenteries, the intensity of infection being 1–165 (mean 30) larvae per fish.The number of catfish examined and their infection with encapsulated P. brooksi larvae is givenin Tab. 6. Larvae were found from June to October with high values of prevalence and meanintensity, except in September, when both values were distinctly low. No larvae were found inNovember, but this may be due to the fact that only two catfish were examined. Tab. 2 shows thatthe rate of infection is associated with the body size (age) of the fish. Values for both the prevalenceand mean intensity decreased with increase in body length of the catfish.Neophilometroides caudatus (Moravec, Scholz et Vivas-Rodríguez, 1995)This nematode is a specific parasite of the swimbladder surface of R. guatemalensis, so far onlyreported from southeastern Mexico from the cenotes Ixin-há and Xmucuy in Yucatán and thePapaloapan River in Veracruz (Moravec et al. 1995a, c, 2002).Occurrence of Neophilometroides caudatus in Rhamdia guatemalensisPrevalence and intensity of infection: Of the 82 R. guatemalensis from this locality, 7 (prevalence9%) were infected with N. caudatus, the intensity of infection being 1–2 (mean 2) nematodes perfish. All nematodes were located under the serosa of the host’s swimbladder.The number of catfish examined and their infection with N. caudatus is given in Tab. 7. Thisparasite was recorded from June to October. Because of its rarity, it was impossible to compare dataTab. 7. Monthly survey of Rhamdia guatemalensis (Günther) from the cenote Ixin-há for infection with Neophilometroidescaudatus (Moravec et al.)month no. of fish examined no. of fish infected prevalence (%) intensity mean (range)June 20 2 10 1.5 (1–2)July 1 7 1 6 2.0 (2)August 14 1 7 2.0 (2)September 14 1 7 1.0 (1)October 15 2 13 1.5 (1–2)November 2 0 – –132
Page 2: Acta Soc. Zool. Bohem. 66: 81-84, 2
Page 5 and 6: REFERENCESBERAN L. & HORSÁK M. 199
Page 7: Tab. 1. Nematodes studied with the
Page 10: Tab. 2. The dimensions (mm) of thir
Page 14 and 15: Family Acuariidae Railliet, Henry e
Page 16 and 17: Fig. 7. Cosmocephalus obvelatus (Cr
Page 18 and 19: A c k n o w l e d g e m e n t sThe
Page 20 and 21: Acta Soc. Zool. Bohem. 66: 99-119,
Page 22 and 23: Figs 1-10. Harpalus (Harpalus) atra
Page 24 and 25: Figs 11-19. Harpalus (Harpalus) cis
Page 26 and 27: Figs 20-27. Harpalus (Harpalus) lut
Page 28 and 29: Figs 28-35. Harpalus (Harpalus) pic
Page 30 and 31: Figs 36-44. Harpalus (Harpalus) sax
Page 32 and 33: Figs 45-53. Harpalus (Harpalus) ser
Page 34 and 35: Figs 54-61. Harpalus (Harpalus) sol
Page 36 and 37: Figs 62-70. Harpalus (Harpalus) xan
Page 38 and 39: Based on the study of our larval ma
Page 40 and 41: EMDEN F. I. van 1942: A key to the
Page 44 and 45: and D. papillifera (Fuhrmann, 1908)
Page 46 and 47: about 1 mm) with only a few eggs in
Page 48 and 49: The number of catfish examined each
Page 50 and 51: number (3.65) of trematodes with ma
Page 54 and 55: from individual months. Tab. 2 show
Page 56 and 57: number (5.57) of males occurred in
Page 58 and 59: intermediate host, copepod, catfish
Page 60 and 61: CHUBB J. C. 1982: Seasonal occurren
Page 64 and 65: efore distal angle of discoidal tri
Page 66 and 67: cells between them and IR2 or MA”
Page 68 and 69: character is less pronounced in Oli
Page 70 and 71: REFERENCESBACHMAYER F. 1952: Fossil
Page 74 and 75: elow) and a 170×90×70 type was us
Page 76 and 77: the brood, first into heaps near th
Page 78 and 79: trophallaxis until the termination
Page 80 and 81: 4. The queen that was accepted was

Gyraulus parvus (Mollusca: Gastropoda) in the Czech Republic

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