Contributions to Zoology, 65 (4) 233-243 (1995)

SPB Academic Publishing bv, Amsterdam

Phylogeny and biogeography of the Ergasilidae (Copepoda,

Poecilostomatoida), with reconsideration of the taxonomic status

of the Vaigamidae

Maria Auxiliadora Pinto da Motta Amado Ju-Shey Ho & Carlos Eduardo Falavigna da Rocha

1 Departamento de Zoologia, Instituto de Biociências, Universidade de Sâo Paulo, Caixa Postai 11294,

2 05422-970 Sao Paulo SP, Brasil; Department of Biology, California State University, Long Beach,

California 90840-3702, USA

Keywords: Phylogenetic analysis, biogeography, Copepoda, , Ergasilidae, Vaigamidae,

Pseudovaigamus gen. n.

Abstract Introduction

of the Nineteen genera are currently considered valid in the Ergasili- family Ergasilidae (Poecilostoma- dae. A cladistic analysis was conducted on these genera and the toida) are found mostly in fresh water and some- five genera composingthe closely allied Vaigamidae. Nineteen times in estuarine and shallow coastal waters. An- morphological characters were selected and polarized using While larval stages and male adults are planktonic, thessius (Anthessiidae) as the outgroup. The most parsimonious

adult female ergasilids are parasitic on teleosts, cladogram(tree length = 60, Consistency Index = 0.50, Reten- tion Index = 0.71), obtained through the use of the BB com- with the exception of Teredophilus spp., which live mand in is of with the Hennig86, composed eight major clades, in bivalve molluscs. five vaigamid genera composing the most derived clade. Based In this paper we attempt to reconstruct the phy- on Wiley’s (1981) “sequencing” convention, the five vaigamid of the the cladistic be in from the togeny Ergasilidae using ap- genera cannot placed a family separate Ergasi-

In order to determine relations between lidae. The biogeography of the ergasilid genera is discussed. proach.

Vaigamus spinicephalus is placed separately in a new genus, Vaigamidae and Ergasilidae, we included four vai- Pseudovaigamus. gamid genera (Gam idactylus, Gamispinus, Gami-

spatulus, and Vaigamus) in the analysis. Amazoni-

copeus Thatcher, 1986, the sole representative of Résumé the Amazonicopeidae, was excluded from the per-

formed analysis because it was foundto be synony-

Actuellement dix-neuf genres d’Ergasilidae sont considérés mous with Therodamas Kroyer, 1863, by Amado Une comme valides. analyse cladistique a été réalisée pour ces (1992) and Abdelhalim et al. (1993). ainsi genres, que pour cinq genres de la famille étroitement ap- According to Ho (1991), the family Gastrodel- parentée Vaigamidae. Dix-neuf caractères morphologiquesont

is the sister of this été choisis et polarisés en utilisant Anthessius (Anthessiidae) phyidae taxon study's ingroup comme outgroup. Le le cladogramme plus parcimonieux (lon- (Ergasilidae-Vaigamidae). However, being para- gueur de l’arbre = 60; index de consistence = 0.50; index de sitic on polychaetes and being highly modified, no retention = obtenu utilisation de la commande 0.71), par BB gastrodelphyid genus serves very well as an out- dans de huit clades les Hennig 86, se compose principaux, cinq to assist in character state polarization for genres de Vaigamidae formant le clade le plus dérivé. Si l’on se group base sur la séquence conventionnelle de Wiley (1981) il n’y a pas Ergasilidae and Vaigamidae. The closest sister de raison de séparer dans une famille indépendante des Ergasili- taxon with the least specialized state of morphology dae les actuellement dans la famille cinq genres placés Vaigami- the are Anthessiidae (Ho, 1991); therefore, type- La dae. biogéographie des genres d’Ergasilidae est discutée. Della genus (Anthessiusi Valle, 1880) was selected as Vaigamus spinicephalusest séparé dans un nouveaugenre Pseu- dovaigamus. the outgroup for this analysis. 234 M.A.P. da M. Amado, J.-S. Ho & C.E.F. da Rocha - Phytogeny and biogeography of Ergasilidae

Material and methods Paratype female. Brazil, State of Amazonas, Amazonas River

(MZUSP-8158).

— jaraquensis Thatcher & Robertson, 1981. Paratype Type-materials of 20 genera were examined in order to verify female. Brazil, State of Amazonas, Amazonas River (MZUSP- character states to be used in the phylogenetic analysis. The 8159). materials and the respective institutions where the specimens are — Ergasilus leporinidis Thatcher, 1981. Paratype female. kept are listed below. The names of the institutions are ab- Brazil, State of Amazonas, Amazonas River (MZUSP-8156). breviated as follows: INPA = Instituto Nacional de Pesquisas

— Ergasilus semicoleus Cressey, 1970. Holotype and paratype de Amazonia, Manaus, Brazil; MZUSP = Museu de Zoologia

females. Australia 125682). Syn. da Universidade de Sâo Paulo, Brazil; NHM = Natural History (NMNH-125681, Dermoerga-

silus. Museum, London; and NMNH = National Museum of Natural — Ergasiluxulus infaltus (Rancurell, 1954). Paratype female. History, Washington DC. Africa, West Lake (NHM-976). Syn. Teredophilus.

— Abergasilus amplexus Hewitt, 1978. Holotype female. New — Gamidactylusjaraquensis Thatcher & Boeger, 1984. Para-

Zealand, Ellesmere Lake (NHM-419). type female. Brazil, State of Amazonas, Amazonas River

— Acusicola lycengraulidis Thatcher & Boeger, 1983. Paratype (MZUSP-8170).

female. Brazil, State of Pará, Tocantins River (MZUSP-8166). — Gamispatulus schizodontis Thatcher & Boeger, 1984. Para-

— Acusicola pelonidis Thatcher & Boeger, 1983. Paratype fe- type female. Brazil, State of Amazonas, Amazonas River

male. Brazil, State of Amazonas, Amazonas River (MZUSP- (MZUSP-8174).

8167). — Gamispinus diabolicus Thatcher & Boeger, 1984. Paratype

— Acusicola tenax Cressey, 1970. Holotype and paratype fe- female. Brazil, State of Amazonas, Amazonas River (MZUSP-

males. Guatemala, Pasión River (NMNH-180760, 125685, 8171).

125686). — Mugilicola australiensis Boxshall, 1986. Holotype female.

— Acusicola tucunarensis Thatcher, 1984. Paratype female. Australia, P. Arrawara (NHM-189).

Brazil, State of Amazonas, Amazonas River (MZUSP-8165). — Neoergasilusjaponicus (Harada, 1930) Yin, 1956. Holotype

— Amazonicopeuselongatus Thatcher, 1986. Paratype female. female. Japan, Jetsugetsutan Lake (NHM-111).

Brazil, State of Amazonas, Amazonas River (MZUSP-8173). — Paraergasilus remulus Cressey, 1970. Holotype and paratype

Syn. Therodamas. females. Cambodja(NMNH-125689, 125690).

— Amplexibranchiusô/ycowis Thatcher & Paredes, 1985. Holo- — Prehendorastrus bidentatus Boeger & Thatcher, 1990. Para-

type female. Perú, Iquitos (MZUSP-8172). type female. Brazil, State of Amazonas, Furo do Catalâo

— Brasergasilus anodus Thatcher & Boeger, 1983. Paratype fe- (INPA-191a).

male. Brazil, State of Pará, Tocantins River (MZUSP-8164). — Rhinergasiluspiranus Boeger & Thatcher, 1988. Holotype fe-

— BrasergasilusjaraquensisThatcher & Boeger, 1983. Paratype male. Brazil, State of Amazonas, Machantaria Island (INPA

female. Brazil, State of Amazonas, Amazonas River (MZUSP- CR 476).

8162). - Thersitina gasterostei(Pagenstecher, 1861). Paratype female.

— Brasergasilus oranus Thatcher & Boeger, 1984. Paratype fe- Locality not known (NHM-727).

male. Brazil, State of Amazonas, Amazonas River (MZUSP- - Vaigamusretrobarbatus Thatcher & Robertson, 1984. Para-

of Machantaria Island 8163). type female. Brazil, State Amazonas,

— Dermoergasilus amplectens Ho & Do, 1982. Holotype and (MZUSP-8168).

paratype females. Russia, Tumen-ul River (NHM-489, 498). - Vaigamus spinicephalus Thatcher & Robertson, 1984. Para-

Tocantins River — Diergasilus kasaharai Do, 1981. Holotype and paratype fe- type female. Brazil, State of Pará, (MZUSP-

males. Japan, Okayama, Kojima Bay (NMNH-184160, 184161). 8169). Syn. Pseudovaigamus gen. nov.

— Ergasilus bryconis Thatcher, 1981. Paratype female. Brazil,

We State of Amazonas, Amazonas River (MZUSP-8155). were not able to obtain specimens of;Sinergasilus,Nipergasi-

— Ergasilus callophysusThatcher & Boeger, 1984. Paratype fe- lus,Pseudergasilus, and Paeonodes for examination. Informa-

male. Brazil, State of Amazonas, Amazonas River (MZUSP- tion on these genera was taken from their original descriptions.

8161). In conductingthe character analysis only adult female charac-

— Ergasilus coleus Cressey, 1970. Holotype and paratype fe- ters were considered. The direction of character transformation

males. Philippines(NMNH-12679, 125680). Syn. Dermoergasi- was made mainly by outgroup comparison, but Huys &

lus. Boxshall's (1991) contention that evolution commonly

— Ergasilus colomesus Thatcher & Boeger, 1983. Paratype fe- is associated with oligomerization is also taken into con-

male. Brazil, State of Amazonas, Amazonas River (MZUSP- sideration.

8157). To avoid confusion, the character states found in the type-

fe- used each For the — Ergasilus holobryconis Malta & Varella, 1986. Holotype species were to represent genus. example, en-

male. Brazil, State of Amazonas, Amazonas River (MZUSP- dopodite ofleg 1 is considered 3-segmented for Ergasilus (with

7011). more than 130 species known), because this is the situation

— Ergasilus hydrolycus Thatcher, Boeger & Robertson, 1984. found in the type-species, E. sieboldi, eventhoughthere are, at Contributions to Zoology, 65 (4) - 1995 235

least, 16 species with 2-segmentedendopoditeforming leg 1. By tennule is due to a failure in division of the second segment

convention, ancestral (i.e., plesiomorphic) states were coded towards the later stages of larval development. Twelve

"0" and derived (i.e., apomorphic) states were coded "1", "2", genera exhibit 5-segmented antennules(Acusicola,Amplexi-

or "3". Higher codes represent further derived states (i.e. "2" branchius,Diergasilus,Gamispatulus,Gamispinus, Mugili- more derived than "1" and "3" more derived than "1" and cola, Paeonodes,Paraergasilus,Prehendorastrus, Teredo- "2"). philus,Therodamas, and Thersitina).

with The phylogenetic computer package Hennig 86 Version 1.5 9. Antenna tipped 4 claws (0), 3 claws (1), 2 claws (2), or

(James S. Farris, 1988) was used to analyze the data summarized 1 claw (3). The terminal armature of the antenna has been

M in Table I. Two algorithms were employed, HENNIG that variously referred to asspines or accessory spines. The heav-

constructs cladograms (trees) by adding the terminals in several iest armature of 3 claws is found only in one genus, viz.

different and retains the shortest and Gami- sequences trees found, BB Paraergasilus.Five genera(Diergasilus,Gamispinus, (branch-breaking) which extends branch-swapping to the trees dactylus,Gamispatulus,and Thersitina)carry 2 claws and

file. the 18 each have claw. to produce a new remaining genera a single

10. Antenna prehensile (0), or chelate (1). The development of

chelate antennaeis rather rare for parasitic copepods. In er-

gasilids, it is only found inAbergasilus and Prehendoras- Characters used in the character analysis surface of the second trus. In these two genera, the medial

bears that segment a large, basal, spiniform protrusion op-

1. Céphalothorax not inflated (0), or inflated (1). The apo- poses the tip of the terminal claw.

morphic state appears in Teredophilus and Thersitina, 11. Antennal segments naked (0), or enveloped with a cuticular

where the fused céphalothoraxis tremendously enlarged. membrane (1). The derived state is found in only three

2. and Metasomal somites well defined (0), or fused (1). The apo- genera: Acusicola,Amplexibranchius, Dermoergasilus.

Pseuder-morphic state is found inMugilicola,Paeonodes, 12. Third antennal segment smooth (0), or bearing a "socket"

gasilus,and Sinergasilus, although traces of segmentation (1). Most gill-parasitizingergasilids and vaigamids attach to

lateral furrows in the last their host the filament the appear as genus. by embracing gill or by piercing

3. Anterior portion of the cephalosome not inserted into host host tissue with the terminal claw. However, in Acusicola

tissue (0), or inserted into host tissue (1). The apomorphic andAmplexibranchiusthere is a "socket" on the third seg-

state is found in Mugilicola, Therodamas, and Paeonodes. ment to receive the terminal claw ofthe opposite appendage

4. Area between head and first pediger not elongated (0), or so as to form a firm, interlocking grasp.

elongated (1). The latter state is shared by Mugilicola and 13. Leg 1 endopodite 3-segmented (0), or 2-segmented (1). Ten

Paeonodes. Brasergasi-ergasilid genera(Acusicola,Amplexibranchius, 5. Rostral spine absent (0), or present (1). The apomorphic lus, Gamidactylus,Gamispatulus,Gamispinus, Prehendo- Pseudovai-state is found in Gamispatulus, Vaigamus, and rastrus,Rhinergasilus,Vaigamus,andPseudovaigamus)ex- gamus. hibit this oligomerization in leg 1.

6. Posterolateral corners of cephalosomerounded (0), or bear- 14. Third segment ofleg 1 exopodite with 8 elements (0), or with

7 ing a spiniform posterolateral protrusion ("retrostylets") elements (1), or with 6 elements (2). Only two genera

(1). The derived state of this character was considered by (Mugilicola and Paeonodes) bear 6 elements (spines and

Thatcher (1991) as the major defining characteristic of the setae), all the other have 7 elements.

& 2 2 vaigamid genera. However, according to Chernysheva 15. Second segment of leg endopoditewith setae (0), or with

Purasjoki's (1991)recent account, this pair of "retrostylets" 1 seta (1). As above, only two genera ((Abergasilus and Der-

is not uniqueto the vaigamids. It is also present in Paraer- moergasilus) exhibit the derived character state.

gasilus. Amado's (1992)reexamination of the type-materials 16. Leg 4 biramous (0), or representedby a seta (1), or leg 4 com-

of vaigamids showed that structural details of the "retro- pletely absent (2). Most ergasilids and vaigamids have bira-

stylets" in Gamidactylus, Gamispinus, and Gamispatulus mous fourth legs. However, inAbergasilus and Rhinergasi-

are different from those found in Vaigamus and Pseudo- lus leg 4 is reduced to a seta and in Brasergasilusand Mugili-

vaigamus. The "retrostylets" in Paraergasilus are similar to cola it is entirely lost.

those found in the latter two vaigamid genera. 17. Leg 4 exopodite 3-segmented (0), or 2-segmented (1), or

Abdominal 7. somites free (0), or fused (1). Three somites are 1-segmented (2), or absent (3). Most ergasilids have fourth

known for both ergasilids and vaigamids, but in Mugilicola, legs with 2-segmentedexopodite, except for the four genera

Paeonodes, and Therodamas they are fused into a unit be- mentioned above that lack leg 4 andNeoergasilus and Paeo-

hind the genital double somite. nodes where there is a single segment. Most vaigamids are

8. Antennule 7-segmented (0), or 6-segmented (1), or 5-seg- distinctive in having fourth legs with 1-segmentedexopodite

mented (2). According to current knowledge onthe develop- but Pseudovaigamus has two segments as the majority of

ment of certain species of Ergasilus(Yin, 1956; Ben Hassine, ergasilids.

Neoergasi-1983; Varella, 1985; Abdelhalim etal., 1991) and 18. Leg 4 endopodite 3-segmented (0), or 2-segmented (1), or

lus four (Urawa et al., 1980) the formation of a 5-segmented an- 1-segmented (2), or basent (3). The ergasilid genera 236 M.A.P. da M. Amado, J.-S. Ho & C.E.F. da Rocha - Phytogeny and biogeography of Ergasilidae

Table I. Character matrix.

Characters

Genera 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19

Abergasilus 0000000131000111332

Acusicola 00000002301 1 1 100101

Amplexibranchius 00000002301 1 1 100101

Brasergasilus 0000000130001 102333

Dermoergasilus 00000001301001 10100

Diergasilus 0000000220000100101

Ergasilus 0000000130000100100

Gamidactylus 000001012000110021 1

Gamispatulus 00001 10220001 10021 1

Gamispinus 0000010220001 100212

Mugilicola 01 1 1001230000202333

Neoergasilus 00000001 30000100220

Nipergasilus 00000001300001001 10

Paeonodes 01 1 1001230000200223

Paraergasilus 0000010210000100100

Prehendorastrus 0000000231001 100101

Pseudergasilus 0100000130000100102

Rhinergasilus 0000000130001 101332

Sinergasilus 0100000130000100100

Teredophilus 1000000230000100103

Therodamas 0010001230000100103

Thersitina 1000000220000100102

Vaigamus 0000110130001100211

Pseudovaigamus 00001 10130001 100101

Anthessius 0000000000000000000

Note: Amplexibranchiusand Acusicola are different from each other in the structure of the antenna and leg I through leg 4. These aut-

apomorphies are not used in the cladistic analysis.

mentioned above with the most derived state of character 17 proach, BB was used and four most parsimonious

also exhibit the most derived state for this character. Unlike obtained with trees were (trees 0, 1,2, and 3) the most of the vaigamids with a 2-segmentedendopodite, the same Consistency Index and a Retention Index of new vaigamid genus Pseudovaigamus has a 3-segmented en- 0.71. dopodite.

19. Free of Of two 0 and segment leg 5 well-developed (0), or reduced (1), or these four cladograms, (trees 2)

represented by a seta (2), absent (3). As shown in Table or presented a pentatomy and were considered least

I, the four states ofthis character are somewhat evenly dis- acceptable. Trees 1 and 3 were selected for further tributed the 24 studied. in the other among genera Again, as considerationbecause they are better resolved. Out characters, the most transformed Paeo- genera (Mugilicola, of these trees, one was chosen to the nodes, and Therodamas) also have the most derived state of represent

this character. hypothesis of the family phylogeny based on the

relative positions of Gamidactylus and Gamispatu-

to- lus to Gamispinus. In tree 1, these three genera Results and discussion form reflects gether a monophyletic group and this

Eight trees were obtained initially, with a length the current view of their relationships (Thatcher,

equal to 60, a Consistency Index of 0.50 and a 1991). This cladogram (tree 1) is reproduced in

Retention Index of 0.70. Later, on a second ap- Fig. 1 along with the other three cladograms. Contributions to Zoology, 65 (4) - 1995 237

Paraergasilus Paraergasilus

Dermoergasilus Diergasilus

Ergasilus Thersitina

Sinergasilus Paeonodes

Mugilicola Nipergasilus

Neoergasilus Therodamas

Abergasilus Teredophilus

Brasergasilus Pseudergasilus Rhinergasilus Rhinergasilus

Paeonodes Brasergasilus Mugilicola Abergasilus

Therodamas Neoergasilus Theredophilus

Thersitina Nipergasilus

Diergasilus Sinergasilus

Pseudergasilus Ergasilus

Dermoergasilus

Amplexibranchius Amplexibranchius

Acusicola Acusicola

Prehendorastrus Prehendorastrus

Pseudovaigamus Pseudovaigamus

Vaigamus Vaigamus

Gamidactylus Gamispatulus Gamidactylus Gamispatulus

Gamidactylus Gamispatulus Gamidactylus Gamispatulus

Gamispinus Gamispinus Gamispinus Gamispinus

BB* Fig. 1. The most parsimonious cladograms obtained through the use of the command in Hennig 86. Tree 2 shows only the part different from tree 0, and tree 3 only the part different from tree 1.

with Establishment of Pseudovaigamus gen. nov. some partly fused first pediger forming a

bullet-shaped céphalothorax. Retrostylets slender

In conducting the character analysis of the vaiga- and curved on posterolateral corner of cephalo- mid genera, it was discovered that Vaigamus spini- some. Rostrum elongated and bearing a thin spine,

free cephalus Thatcher & Robertson, 1984 differs so dilated near base. Four pedigers decreasing in much from the type-species of Vaigamus (V. retro- width posteriorly. Genital double-somite hexa- barbatusThatcher & Robertson, 1984) that it must gonal. Three free abdominal somites. Anal somite be placed in a separate genus. Accordingly, Pseu- with median notch. Caudal rami longer than wide

dovaigamus is erected here to facilitate this trans- with a notch on outer lateral border, where there is fer. a seta; terminally with two long setae and two

lobules; innermost element spinulose on ventral

Genus definition. - Female: and element dorsal Ergasilidae. Cephalo- surface, outermost smooth on 238 M.A.P. da M. Amado, J.-S. Ho & C.E.F. da Rocha - Phytogeny and biogeography of Ergasilidae

surface. Antennule 6-segmented. Antenna 3-seg- Phylogeny and classification mented (coxobase and endopodite bi-segmented) with curved and first seta. a claw, segment bearing a The phylogenetic tree illustratesthat the five genera

without 1 4 biramous. Maxillule setae. Legs to Leg of Vaigamidae (clade VIII of Fig. 2) are monophy-

1 with 2-segmented endopodite. Legs 2 and 3 with letic, sharing the apomorphic states of character 5 both rami 3-segmented. Leg 4 with 2-segmented (rostral spine present) and character 6 ("retrosty-

and 5 exopodite 3-segmented endopodite. Leg re- let" on cephalosome). However, based on Wiley's duced to two setae. Egg sacs short with few eggs in (1981) "sequencing" convention, the five vaigamid

female free in a single row. Ovigerous . genera (Gamidactylus, Gamispatulus, Gamispinus,

Male: Shape of body similar to female, without Vaigamus, and Pseudovaigamus ) cannot be treated

rostral Genital somite sub-rec- retrostylets or spine. as a family separate from the Ergasilidae. If they

with median notch. Four abdominal tangular, a are given a familial status, the 19 ergasilid genera

Pre-anal somite each somites. bearing a spine on will have to be classified into seven separate fami-

Anal somite also posterior corner. bearing a spine lies or else these would be left as a paraphyletic at same place as in latterand with onemedian notch. taxon. Since such splitting of the Ergasilidae would

terminal thin and Maxilliped 4-segmented; segment create much taxonomie problems, we propose to straight. Leg 5 with same structure as in female. Leg followthe phylogeny inferred in Fig. 1 and consider

6 reduced to seta one projecting posterolaterally the five vaigamid genera as the most derived mem- from genital somite. Free in plankton. bers of the Ergasilidae.

In Fig. 2, the branches that leadto Paraergasilus,

Type-species. - Pseudovaigamus spinicephalus Diergasilus, Thersitina, and Pseudergasilus each (Thatcher & Robertson, 1984). By present designa- form a cluster of their own, but the remaining 20 tion. form four clusters each genera generic (clades),

with at least one unifying character (synapomor- Etymology. — The new genus name refers to its phy). The largest of these four clades (clade VI) is similarity with Vaigamus Thatcher & Robertson, of the " " composed eight including Erga- 1984; pseudo is Greek for "false". genera, genus silus which alone contains about 75% of all known

Remarks. — The new genus differs from Vaigamus ergasilid species. The three genera of clade VII are

unified antennule chiefly in the segmentation of leg 4. In Vaigamus by having a 5-segmented (the this pair of legs has a 1-segmented exopodite and a most derivedstate of character 8). Mugilicola, Pae-

2-segmented endopodite, but in the new genus, the onodes, Teredophilus, and Therodamas are united plesiomorphic state remains (2-segmented exo- together in clade IV only by the loss of leg 5 (the podite and 3-segmented endopodite). Additionally most derived state of character 19). This last clade

unusual caudal rami is also the the most transformed Pseudovaigamus possesses one containing with the mediodistal corner protruded into a spinu- ergasilids. lose lobe. Based on Wiley's (1981) "sequencing" conven-

the clades in 2 to be called Pseudovaigamus differs fromall other genera by tion, eight Fig. are eight the of subfamiliesof the consider- presence a rostral spine in the ventral face of Ergasilidae. However, the with and oriented that freshwater and coastal of cephalosome a dilated basis ing many

the of South America be examined for their to posterior part the body, and by caudal are yet to rami with terminal lobules. These differences were ergasilid copepods and that more new taxa are yet

think it is still detected by examination of the paratype MZUSP to be established, we premature to

8169 B, deposited in the Museu de Zoologia da designate formally the subfamilial status of the

Universidade de Sào Paulo, Brazil. eight clades. Contributions to Zoology, 65 (4) - 1995 239

Paraergasilus

Diergasilus

Ther sitina

Paeonodes

Mugilic ola

Therodamas

Teredophilus

Pseudergasilus

Rhinergasilus

Brasergasilus

Abergasilus

Neoergasilus

Nipergasilus

Sinergasilus

Ergasi lus

Dermoergasilus

Amplexibranchius

Acusicola

Prehendorastrus

Pseudovaigamus

Vaigamus

Gamidactylus

Gamispatulus

Gamispinus

Fig. 2. Cladogram of the Ergasilidae. The Roman numerals refer to the clades discussed in the text. - 240 M.A.P. da M. Amado, 7.-5. Ho & C.E.F. da Rocha Phytogeny and biogeography of Ergasilidae

Paraergasilus

Diergasilus

Thersitina

Fig. 3. Distribution ofParaergasilus (clade I), Diergasilus (clade II), and Thersitina (clade III).

Paeonodes

Mugilicola

Therodamas

Teredophilus

Fig. 4. Distribution of Paeonodes, Mugilicola, Therodamas, and Teredophilus (clade IV). Contributions to Zoology, 65 (4) - 1995 241

Pseudergasilus

Rhinergasilus

Brasergasilus

Abergasilus

Neoergasilus

Nipergasilus

Sinergasilus

Dermoergasilus

Fig. 5. Distribution of Pseudergasilus from clade V and Rhinergasilus, Brasergasilus, Abergasilus, Neoergasilus,Nipergasilus, Sinergasi-

VI. VI in lus, and Dermoergasilusfrom clade Ergasilus from clade is world-wide distribution and omitted from this map.

Amplexibranchius

Acusicola

Prehendorastrus

Pse udovaigamus

Vaigamus

Gamidactylus

Gamispatulus

Gamispinus

Fig. 6. Distribution ofAmplexibranchius,Acusicola, andPrehendorastrus from clade VII andPseudovaigamus, Vaigamus, Gamispatu-

lus,Gamidactylus, and Gamispinus from clade VIII. 242 M.A.P. da M. Amado, J.-S. Ho & C.E.F. da Rocha - Phytogeny and biogeography of Ergasilidae

tribution of the members of this clade is thought to

wide be a result of their utilization of spreading

coastal such as needlefish and mullet.A similar

pattern is found inDermoergasilus and Neoergasi-

lus (clade VI, see Fig. 5). The remaining members

of the last-mentionedclade, with the exception of

Ergasilus, are ratherrestricted in their distribution,

possibly due to their utilization of narrowly dis-

tributed freshwater hosts. The members of clades

VII and VIII are essentially confined to South

America, particularly the Amazon Basin (Fig. 6).

Acusicola is the only exception, with some of its

members reaching as far as Texas to the North. As

in the case of Dermoergasilus and Neoergasilus,

this distributionpattern may be due to the utiliza-

tion of coastal euryhaline fishes as hosts.

Twelve of known from genera ergasilids are Acusicola Brazil include all members of the Amplexibranchius (Fig. 7). They

Brasergasilus most derived genera (cf. Fig. 2), from clade VII and Ergasilus clade VIII, plus three genera (Ergasilus, Braserga-

Gamidactylus silus, and Rhinergasilus) from clade VI and one Gamispatulus Therodamas from clade IV. Aside from Er- Gamispinus genus( )

Prehendorastrus gasilus, which is cosmopolitan, these Brazilian er-

Pseudovaigamus confined the gasilids are essentially to Amazon Rhinergasilus of the Basin. This high diversity (12/24 or 50% Therodamas

Vaigamus from the known genera Amazon Basin) suggests

that ergasilids may have gone through an explosive

cladogenesis in the Amazon Basin, probably in as- Fig. 7. Distribution of ergasilid genera in Brazil.

sociationwith a similar radiationof their fish hosts.

Given these patterns, we feel confident that many

ergasilids are yet to be discovered on Amazon Biogeography fishes.

Anhypothesis on historical biogeography can some- times be deduced from a cladogram. From these Acknowledgements phylogenetic studies, some patterns of ergasilid dis- tribution are apparent.Paraergasilus is found in This work was supportedby a grant from the Brazilian Ministry Eurasia, Africa, and Australia (Fig. 3). Its absence of Education and CAPES to the first author (M.A.P. da M. from the New World suggests that this new genus Amado). The authors gratefully acknowledge the help and the evolved after the widening of the Atlantic Ocean. favourable research facilities offeredby the Department of Biol-

On the the distributionof contrary, amphi-Atlantic ogy of California State University, Long Beach, USA, and by

Thersitinawould indicate that it evolved before the the Departamento de Zoologia and Museu de Zoologia da

Universidade de Sào Paulo, Brazil. They also thank the Natural birth of this ocean. The genus is host-specific to History Museum,London, in the person ofDr. Geoff Boxshall, sticklebacks (Pisces, Gasterosteidae). the Smithsonian Institution, Washington,USA, particularly Dr. The distributionpattern of the most transformed Janet Reid, and the Instituto Nacional de Pesquisas da Amazo- ergasilids see seems to that (clade IV, Fig. 4) suggest nia, Amazonas, Brazil, for help in obtaining the type materials these in Gondwana. The wide dis- of in these Institutions. generaoriginated the ergasilids and vaigamids deposited Contributions to Zoology, 65 (4) - 1995 243

References Thatcher, V.E., 1991. Amazon fish parasites. Amazoniana, 11 :

263-571.

Thatcher, V.E. & B.A. Robertson, 1984. The parasitic crusta-

Abdelhalim,A.I., J.W. Lewis & G.A. Boxshall, 1991. The life- ceans of fishes from the Brazilian Amazon. 11. Vaigamidae

males cycle of Ergasilus sieboldi Nordmann (Copepoda-Poeci- fam. nov. (Copepoda: Poecilostomatoida) with and fe-

V. lostomatoida), parasitic on British freshwater fish. J. nat. males of Vaigamusretrobarbatus gen. et sp. nov and spini-

Hist., 25: 559-582. cephalussp.nov. from plankton. Can. J. Zool., 62: 716-729.

Amado, M.A.P. da M., 1992. Ergasilideos parasitas de peixes Urawa, S., K. Muroga& S. Kasahara, 1980. Naupliar develop-

de águas continentais brasileiras (Copepoda: Poecilostoma- ment of Neoergasilus japonicus (Copepoda: Ergasilidae).

46: toida), com urna hipótese de filogenia da familia: 1-204 (un- Bull. Jap. Soc. scient. Fish., 941-947.

published Ph.D. dissertation, Universidade de Sâo Paulo). Varella, A.M.B., 1985. O ciclo biològico de Ergasilus bryconis

Ben Hassine, O.K., 1983. Les Copépodes parasites des poissons Thatcher, 1981 (Crustacea, Poecilostomatoida, Ergasilidae)

Mugilidae en Mediterranée occidentale (côtes françaises et parasita das brânquias do matrinxâ, Brycon erythropterum

— sua (unpublished tunisiennes); morfologie, bio-écologie, cycles évolutifs: 1 (Cope, 1872) e aspectos de ecologia: 1-100

432 (unpublished Ph.D. dissertation, Université des Sciences M. Sci. dissertation, Instituto Nacional de Pesquisas da

et Techniques du Languedoc). Amazonia, Manaus).

Chernysheva, N.B. & K.J. Purasjoki, 1991. A redescription of Wiley, J., 1981. Phylogenetics: the theoryand practice ofphylo-

Paraergasilus rylovi Markewitsch, 1937 (Copepoda: Poeci- geneticsystematics: 1-439 (John Wiley & Sons, New York).

lostomatoida). Syst. Parasitol., 2: 165-171. Yin, W.Y., 1956. Studies of the Ergasilidae (parasitic Copepo-

Ho, J.S., 1991. Phylogeny ofPoecilostomatoida: a major order da) from the freshwater fishes of China. Acta hydrobiol. Sin.,

of symbiotic copepods. Bull. Plankton Soc. Japan, Spec. 1956 (2): 209-270.

Vol.: 25-48.

Huys, R. & G.A. Boxshall, 1991. Copepod evolution: 1-468 Received: 28 October 1994

(Ray Society, London). Revised: I September 1995