NNFE391015 8/17/04 2:13 PM Page 15 Studies on Neotropical Fauna and Environment 2004, Vol. 39, No. 1, pp. 15–35 New species of Ichthyocladius Fittkau, a Member of the Corynoneura-Group (Diptera: Chironomidae: Orthocladiinae), with a Review of the Genus Humberto F. Mendes1, Trond Andersen2 and Ole A. Sæther2 1Department of Biology-FFCLRP, University of São Paulo, Ribeirão Preto, Brazil 2Museum of Zoology, University of Bergen, Bergen, Norway Abstract Emended diagnoses of all stages of the genus Ichthyocladius Fittkau (1974) mentioned several larvae of the genus Fittkau are given. The genus appears to be a basal member from Trinidad, Venezuela, Guyana, Bolivia and Brazil not of the Corynoneura group showing affinities also to the Euki- identified to species. In the present paper all stages of two efferiella group. A number of features apparently are the new Brazilian species and the pupal exuviae of two addi- result of the phoretic life on catfishes. Ichthyocladius kro- tional species from Brazil and Argentina are described and nichticola sp. n. and I. lilianae sp. n. are described and figured. figured in all stages. Additional pupae from the Amazonas in Brazil and from the Parque Nacional Iguazú in Argentina are also described and figured. Keys to pupae and larvae of the Material and methods genus are given. The general terminology follows Sæther (1980). The male Keywords: Chironomidae, Orthocladiinae, Corynoneura – hypopygium is figured with tergite IX removed, dorsal group, Ichthyocladius, new species, Brazil, Argentina. aspect to the left, and ventral aspect to the right. Dorsal view of tergite IX, gonocoxite and gonostylus are figured separately. Introduction All material is mounted on microscope slides and prepared in Canada Balsam or Euparal. The holotypes Fittkau (1974) erected the genus Ichthyocladius for two and paratypes of the new species are deposited at the species from Peru and Ecuador. The larvae of the genus live Museu de Zoologia da Universidade de São Paulo, Brazil phoretically on catfishes of the families Astroblepidae and (MZUSP). Paratypes are also deposited at the Zoologische Loricariidae, attaching themselves to the skin and scales of Staatssammlung, Munich, Germany (ZSM), and at the the fish. At the end of the fourth larval stage the larvae spin Museum of Zoology, University of Bergen, Norway a holdfast that is attached to spines or fin rays and finally (ZMBN). formed into a pupal case. The only named species, I. neotrop- icus Fittkau, was described based on pharate pupae and asso- ciated larvae. Several details, especially concerning the Ichthyocladius Fittkau wings and the apodemes of the male hypopygium, thus have not been described previously. Ichthyocladius Fittkau 1974: 91. Received: 19 January 2003 Accepted: 21 November 2003 Correspondence: T. Andersen, Museum of Zoology, University of Bergen, Muséplass 3, N-5007 Bergen, Norway. Fax: +47 55589677; E-mail: [email protected] DOI: 10.1080/01650520412331270936 © 2004 Taylor & Francis Ltd. NNFE391015 8/17/04 2:13 PM Page 16 16 H.F. Mendes et al. Type species and some apical ventrolateral setae; laterosternite IX bare. Sternapodeme strong, triangular. Phallapodeme and aedeagal Ichthyocladius neotropicus Fittkau, 1974, by original desig- lobe normally developed. Virga absent. Gonocoxite well nation and monotypy. developed, superior volsella apparently absent, inferior volsella low to moderately well developed. Gonostylus Other included species broadest near apex, without crista dorsalis and megaseta. Female genitalia with well developed gonocoxite with Ichthyocladius kronichticola sp. n.; Ichthyocladius lilianae several setae. Tergite IX very large, covering most of geni- sp. n.; Ichthyocladius sp. Ecuador; Ichthyocladius sp. Rio talia, medially divided, with several apical setae. Segment X Marauiá, Brazil; Ichthyocladius sp. Argentina. apparently normal. Postgenital plate weak or absent. Cercus triangular, small. Gonapophysis VIII undivided. Shape of apodeme lobe and coxosternapodeme unknown. Seminal Diagnosis capsules much larger than cerci, ovoid; with orally placed Imago. Small species, wing length about 1.3mm. neck. Spermathecal ducts nearly straight, apparently with Eye bare, rounded, no dorsomedian elongation. Antenna common opening. Labia not known. with 12 (or perhaps sometimes fewer, see below) flagellom- eres in male, six in female; male antenna sparsely plumed; Pupa. Small pupae, about 2–3mm long. Exuviae nearly groove beginning on flagellomere 3; sensilla chaetica minute, transparent to strongly marked with brown. present on flagellomeres 2, 3 and 12; apex without straight Cephalic tubercles and frontal warts absent. A low protu- apical seta; AR lower than 0.4. Only one palpomere, no sen- berance densely covered with tubercles present basally on silla clavata. Temporals consisting of a few minute inner and pedicel. Frontal setae absent, frontal apotome wrinkled. Tho- outer verticals (or sometimes absent?). Tentorium with broad racic horn absent. Wing sheath smooth, without pearls or but short base, stipes apparently normal. Cibarial pump nose, but sometimes with notch. Thorax with median tuber- broad, but short, with concave anterior margin and well cle. Three precorneals, four antepronotals, at least one pos- developed, triangular cornua. Clypeus narrow with short torbital, and four dorsocentrals present, all minute. lateral setae. Segment I and sternite IX without shagreen; tergites and Antepronotal lobes broad, collar-like, not medially nar- sternites II–VIII with shagreen, on tergites II–VII median rowed, without setae. Scutal tubercle present and prominent. shagreen spinules stronger and sometimes placed on protu- Acrostichals absent, dorsocentrals uni-triserial, several pre- berance. Conjunctives bare. Tergites II–V and sternites alars, supraalar present. Scutellum with setae transversely IV–VII each with 34–50 caudal hooklets; a few lateral or uniserial. median hooklets sometimes present also on tergite I and/or Wing broad, with well developed, but not projecting anal sternite III. Pedes spurii A and B absent. lobe; membrane with distinct punctation; costa slightly Abdominal setae minute; segments I–V each with 1L extended; veins R and R short, thick and fused with costa 1 2+3 seta, VI–VII with 1–2L setae, VIII with four L setae; tergites in thick clavus, ending slightly beyond midpoint of wing; I–VI with four, VII with three and VIII with one pair of D R weak; VR moderately high; Cu slightly sinuous; postcu- 4+5 1 setae; sternite I with three, II with four, III–VII with five, and bitus ending distal to cubital fork, anal vein ending below or VIII with two pairs of V setae. Segment IX with three short, slightly distal to cubital fork. Brachiolum with one seta, other scimitar-like or hair-like curved macrosetae situated ven- veins bare. Squama bare. Sensilla campaniformia about eight trally or at apex. O setae not observed. Genital sac of male basally and eight apically on brachiolum, apparently none slightly to much longer than anal segment, broadly rounded, below setae on brachiolum; one present basally on subcosta, without shagreen or apically wrinkled and with a few minute and one on RM. apical spinules. Front leg ratio high, about 0.8. Front tibia with straight, weak spine-like tibial spur; spurs of mid tibia either with thorn-like lateral denticles or entirely consisting of thorn-like Larva. Small larvae, up to 7mm long. spines; hind tibia with well developed spurs covered with Antenna with four segments, basal segment about as long thorn-like lateral denticles; hind tibial comb absent or as or slightly longer than flagellum, second antennal segment reduced to a few setae. Short tarsal pseudospurs present on slightly longer than or subequal to third. Basal antennal metatarsi of mid and hind legs and ta2 of mid leg. Pulvilli segment 1.5–2 times as long as basally wide, with ring organ absent. No sensilla chaetica observed. situated in apical third. Lauterborn organs not observed, style Tergites II–VII in male, II–VIII in female each with group well developed. Blade slightly shorter than flagellum, acces- of median setae sometimes on a low protuberance, tergites sory blade about half as long. except for male tergite IX otherwise bare; sternites except for S I pectinate to plumose. Other S setae simple. Labral female sternite VIII bare. lamella large, bluntly triangular with about 50 teeth. Chaetae Tergite IX of male large, covering much of gonocoxites, reduced to two pegs. Pecten epipharyngis consisting of three with notched or bilobed posterior margin, with several apical pointed teeth. About six chaetulae laterales with the median NNFE391015 8/17/04 2:13 PM Page 17 New Species of Ichthyocladius 17 apparently serrated, chaetulae basales weak. Premandible Characters in common for all the genera of the two groups with three distinct dark inner teeth and 3–5 broadly lamel- include absence of pedes spurii A and B of the pupa; sex late, pale and fused outer teeth (not visible in all views), dimorphism of sternite VIII of the pupa; gonapophysis VIII without or with vestigial brush. of the female genitalia undivided; and ventromental plates of Mandible with long, bent apical tooth longer than com- the larvae narrow, inconspicuous, widest posteriorly and bined width of 3–4 inner teeth. Seta subdentalis well devel- without setae underneath. oped. Seta interna absent. Ichthyocladius, in addition to the possession of a clavus, Mentum with 16–20 equal-sized small median teeth shares the reduced temporals, the large tergite IX covering nearly in