AMAZONIANA VIII J 321 - 326 Kiel, Juni 1984

The Parasitic Crustaceans of from the Brazilian Amazon, 12., Ergasilus n. sp. (Copepoda : Poecilostomatoida) from Hy droly cus sco mberoides (CUVIER)*

by

Vernon E. Thatcher, Walter A. Boeger and Barbara A. Robertson

lnstituto Nacional de Pesquisas da Amazônia, Manaus, Amazonas, Brasil

Abst¡act The female of Ergasílus hydrolycus n. sp. is described from specimens taken from the gills of an Amazonian , Hydrolycus scomberoides (CUVIER). The new is similar to E bryconis THATCHER, 19E1, and to E. iaraquens¡ï THATCFIER & ROBERTSON, 19E2, in the form of the body, antennae and legs, and in having a curved pectinate seta on the terminal segment of the first exopod. The new species is distinguished from the other two by having a single seta representing the fifth leg, instead of two, and by having a relatively larger antennal claw. .{dditionally, the pigmentation ofE hydrolycus n. sp, is limited to a single transverse band at the level of the mouth while in the other two species it is diffuse and distributed throughout the body. Àlso, the uropod of the new species has two main setae and that of E, bryconß has three. The new species is læger than E iaraquensis.

Keywords : Farasitism, Crustaceans, f ishes, Amazon.

Introduction

In the preænt series of studies (THATCHER 1981a, 1981b; THATCHER & ROBERTSON 1982; THATCHER & BOEGER 1983 and in press) fìve species of Eryasilas have been described, namely: E bryconis ftom&rycon melanopterus (COPE),,E. leporini-

di s from L eporínu s fa sciatus (BLO CH),,8'. j araqu e n s is fr om S e møpro chíb dus insignis (SCHOMBURGK),8. colomesrs from Colomesus asellus (MUELLER &TROSCHEL) and E. callophysus from Callophyus rnacropterus (LICHTENSTEIN). The present paper presents the description of the sixth species of the known from the Amazon River basin.

* This stgdy was done as a part of the project "Ecology of the Amazonian Floodplain", which is being conducted under a cooperative agreement between the Brazilian National Institute for Amazonian Resea¡ch (INPA), Manaus, Brazil,and the Department of Tropical Ecology of the Max-Planck-Institute, West Germany.

0065-6755 I L9E4 | 32L | @ MPI fü¡ Limnologie, AG Tropenökologie, Plön;INPA, Manaus

32t Material and Methods Discussion

Ergasilids were removed from the fish gills, killed and fixed in 70 % aløhol and the methods Ergøsilus hydrolycus n. sp. has a saw-ïke pectin¿te seta on the termin¿l segment of the first used in their preparation we¡e those explained in THATCFIER (19E1a) and in THATCHER & ROBERT- s(opod which suggests its affinity lo E. bryconis THATCIIER 1961, and to E. iaraquensr's THATCFIER (19E2). SON Colo¡ determinations we¡e made with ¡efe¡ence to SMITFIE (1974). Drawings were made & ROBERTSON 19E2. The pigmentation of the new species is confined to a transverse ba¡d near the with the aid of a camera lucida and measurements with an ocula¡ micromete¡. All measurements are ex- mouth, however, while in the other two species it is widely dist¡ibuted tlroughout the body. The new pressed in micrometers. species has a fifth leg represented by a single æta while there a¡e two setae in the othe¡ two species. Of tlre three species, .8. joroquensis is the smalþst (6E0 - 750 ¡rm; compared with 820 - 860 fo¡ ^8. bryconis and 725 - E75 for.E. hydrolycus n. sp.). Although the second antenna of the th¡ee is similar, that of Systematic Section E. iaraquensis has a claw that is less than one thfud the length of the second segment while in the other two species this ratio is about one to two. Additionally, the uropod of E. hydrolycus n. sp. has only Ergasilidae NORDMANN, lB32 two main setae while that of .E'. bryconis has th¡ee. Ergasilus hydrolycus n. sp. (Figs. 1 - lt) Host: Hydrolycus scomberoides (CWIER); Cynodontidae. Resumo Site: Gill filaments. Locality: Marchantaria Island, neæ Manaus, Amazonas, Brazil. A fômea de Ergasilus hydrolycus n. sp. é descritâ de espécimens removidos das brânquias de um Male: Unknown. peixe amazônico, Eydrolycus scombetoides (CWIER). A nova espécie assemelha-se comE. bryconis (female): Holotype Instituto Nacional de Pesquisas da Amazônia (INPA), Manaus, Amazonas, Brazil, THATCHER 19E1, e comE jaraquensis THATCHER & ROBERTSON 19E2, na forma do corpo, pA-240-1. No. antenas e pemas, e especialmente na presença de uma seta pectinada e curvada no segmento terminal Paratypes: INPA and Museu de Zoologiada Universidade de São Paulo, São Paulo, S. p., Brazil. do primeiro exopódito. A nova es¡Écie distingue-se destas por ter só uma seta, e não duas, representando Etymology: The specific name of the parasite is taken from the generic name of the host. a quinta pata e uma garra antenal relativamente maior. Também, a pigmentação de E. hydrolycus n. sp. (based Species diagnosis on 17 specimens studied and 10 measured; Tables I & II: Cephalothorax é limitada a uma banda transversal ao nível com a boca, enquanto a das outras duas espécies é difusa e bullet-shaped, bluntly rounded anteriorly. Eye prominent, 3{obed, cobalt blue (Color 68 of SMITHE distribuida pot todo o corpo. Adicionalmente, o urópodo da nova espécie tem duas setas principais e o 1974). Cephalosome with spectrum blue (Color 69) band ventrally at level of mouthparts (F¡g. 3). de E, bryconß tem três. A nova espécie é maior do que E, ioraquensis. Thorax @ig. 3) with segment 2 incompletely fused to cephalosome. Genital segment sub- rectangular (Frg. t). Abdomen (Flg. 1) 3-segmented; second segment shorter than other two. Uropod (Fig. 2) with References two principle setae (one shorter than other) and two small setae and few spinules. Antennule (Ftg. 4) of six segments bearing simple setae; setalformula = 1 - E -3 -4 - 3 -5;total = SMITHE, F.B. (1974): Naturalist's Color Guide and Supplement. Amer, Mus. Nat. Hist.- New York, 24. Prehensile antenna (Flg. 6) 4 segmented; basal segment with small terminal spine; segment 2 ì¡¡ith N. Y., Colors I - E6 & 229 pp. inconspicuous slit-like sensillum distally; segment 3 with projecting sensillum proximally and pore-like THATCHER, V. E. (19Ela): Os crustáceos parasitos de peixes da Amazônia b¡asileira. l. Ergasílus ænsillum distally; claw slightly curved with small pore-like sensillum near point: ratio of segmintal bryconis n, sp. (Copepoda : Cyclopoidea) da matrinchã (Brycon melønopterus (COPE)).- Acta lengths=L:2:1.7:1. Amazônica ll: 439 - 444. Mouthparts €tg. 8). Ma¡dible bristled posteriorly: palp serrate posteriorly; malillule vestigial; TÍIATCHER, V. E. (19E1b): Os crustáceos parasitos de peixes da Amazônia b¡asileira. 2, Ergasilus maxilla rasp-like with terminal segment. leporinídís n. sp. (Copepoda : Cyclopoidea) das branquias de Leporinus lasciotus (BLOCH).- Legs 7 9, r0 & I 1). Leg (Ft. @igs. ' I ?) : endopod two-segmented, exopod three-segmented: Acta Amaaônica 11:'123 - 727. first endopodal segment with spinules laterally and with one plumose seta medially; te¡minal segment THÀTCHER, V. E. & W. A. BOEGER (19E3): The parasitic üustaceans of fishes from the Brazilian with two plumose stout spines and five setae: first exopodal segment with one stout late¡al spine and Amazon, 4. Ergasilus colomesus n. sp. (Copepoda : Cyclopoida) from an ornamental fish, few spinules ald hairs; second segment with spinules laterally and with one plumose seta medially; Colomesus asellus (Tetraodontidae) and aspects of its pathogenicity.- Trans. Amer. Mic. Soc. terminal segment with two stout spines, one saw-like curved pectinate seta ¿nd four plumose setae. lO2:3'lL - 3'19. Leg Z Leg (FU. 1= 3): both rami 3-segmented 9): first endopodal segment pilose laterally and with one THATCÍIER, V. E. & W. A. BOEGER (in press): The parasitic crustaceans of fishes from the Brazilian plumose seta medially; second segment with two plumose setae medially; terminal segment with one Amazon. 9, Ergasihts callophysus n, sp. (Copepoda : Cyclopoida) ftom Callophysus møøopterus slender spine and four plumose setae: first exopodal segment pilose medially and with one slender spine (LICHTENSTEIN).- P¡oc. Helm. Soc. \ilash. and few spinules laterally; second ægment with spinules laterally and one plumose seta medially; ter- THATCHER, V. E. & B. A. ROBERTSON (19E2): The parasitic crustaceans of fishes from the Brazilian minal segment with spinules laterally and with one slender spine and six plumose setae. Leg 4 (Fig. l1): Amazon. 3. Ergøsifus iaraquensís n. sp. (Copepoda : Cyclopoidea) from the gills of Semaprochi- both rami two-segmented: first endopodal segment with one plumose seta medially; terminal segment lòdus ínsignis (SCHOMBURGK).- Rev. Brasil. Biol. 42: 515 - 5t9. with one slender spine and five pluinose setae:.first exopodal segment pilose medially and with óne slender spine laterally;te¡minal segment with one slender spine and four plumose setae. Basipods of legs I 4 provided ' with single simple setae. Leg 5 (Frg. 10) vestigial, consisting of one simplcseta arising Autho¡¡' addresses: Accepted for publication in December 19E3 from small papifa. D¡. Vernon E, Thatcher Egg sac (Fig. 5) elongate, with ?0 - 60 eggs. lvl Sc. \À'alter A. Boegcr M. Sc. Ba¡bara Robertson Instituto Nacional de Pesquisas da Amazônia INPA _ DBL Q 47E 69.000 Manaus, Amazonas 322 Brasil 323 Table 1: Measurements (¡.rm) of 10 Adult Females of Ergasilus hydrolycus n. sp.

Length width Body (less caudal setae) 725 - 87s (784) 260 - 3t0 (2'18) Cephalothorax 270 - 300 (290) 260 - 3t0 (278) Free tho¡acic segments II 105 - 120 (113) 230 - 270 (2ss) III 70- E1('.t1) 180 - 21s (19E) Iv 62- 7s ( 70\ 12s - 170 (140) v s0- 62( s8) 90 - 112 (101) VI 1,s- 22( L7) 70- 80( 7s) VII Genital) ss- 72( 70) 77- 87( 83) Abdominal segments I 12- r7 ( ts) ss- 62( s6) ü 7 - L2( L0) s0- ss( s3) il 2s- 30( 28) ss- 57( 56) Uropod 4s- s0( 48) 22- 2s ( 23) Caudal setae 200 - 270 (238) I Egg mc 310 - 470 (393) 50- 60( 56)

3 4

Table 2: Antennal measurements (¡rm) of 10 adult females of Ergasilus hydrotycus n. sp.

Length width Antennule 150 - 1?0 (162) 32 - 40 (3't) Antenna Segment 1 E2 - r22 (104) 60 - 70 (66) 2 200 - 232 (217) s7 - 7s (67) 3 172-197 (rEs) 2s - 28 (27) 2 4 97 - 105 (101) 20 - 22 (2t)

5

Plate I: Ergasilus hydrolycus n, sp. (female). Fig. 1. Genital segment, abdomen and uropods. Fig. 2. Uropod, ventral aspect. Fig. 3. Dorsal view of entire specimen. Frg. 4. Antennule. Fig. 5. Egg sac. (scale in pm).

324 325 õo

6

-l 7 I

lo

il

Plate II: Ergasilus hydrolycus n. sp. (female), Fig. 6. AntennuFrg. T. Leg 1. Fig. E. Mouthparts. Fig. 9. Leg 2 (= Lee 3). Fig. 10. Leg 5. Fþ. 11. Leg 4. (scale in ¡.¡m).

326