NEW SPECIES OF XESTOCHIRONOMUS SUBLETTE AND WIRTH (CHIRONOMIDAE: CHIRONOMINAE) FROM CHILE AND COSTA RICA
1998; Kansas (Central States) Entomological Society; Volume: 71; Issue: 3 Linguagem: Inglês
ISSN
1937-2353
AutoresT. Andersen, Lina Kristoffersen,
Tópico(s)Coleoptera Taxonomy and Distribution
ResumoXestochironomus aisenensis n. sp. from southern Chile is described and il lustrated as male and female imagines and Xestochironomus laselvensis n. sp. from Costa Rica is described as male imago. The genus Xestochironomus Sublette and Wirth, 1972 is known from the New World only, and has been recorded from Peru, Venezuela, Panama, Guatemala, and the Caribbean islands, and from Florida, South Carolina, Texas and New Mexico in the United States (Borkent, 1984; Sublette and Sasa, 1994; Sublette and Wirth, 1972). The larvae are highly modified wood miners and are found in pieces of well formed wood, clean from surface contamination in lotic habitats (Borkent, 1984). The type species of Xestochironomus is X. furcatus (Johannsen, 1938), described as Chironomus (Stenochironomus) furcata. Sublette (1967) erected the genus Insu lanus Sublette, 1967 for the species, a name which proved to be preoccupied. Sub lette and Wirth (1972) thus introduced the name Xestochironomus as a replacement name for Insulanus Sublette, 1967 nee. Fleutiaux, 1933 and described 6 new spe cies. Borkent (1984) in his revision of Xestochironomus, Harrisius Freeman and Stenochironomus Kieffer added five new species. Later, Sublette and Sasa (1994) described one new species from Guatemala. Borkent (1984) provided a key to male imagines of Xestochironomus and outlined the phylogeny of the Stenochironomus complex. In the present paper one new species of Xestochironomus from southern Chile and one new species from Costa Rica are described. Borkent (1984) mentioned that he had examined specimens of an undescribed Xestochironomus species from southern Chile (Lago Llanquihue, Lago Todos los Santos, Lago Villarica and Lago Pellaifa), but that he considered the specimens too bleached by long storage in alcohol to al low them to be adequately described. So far there seems to be no records of Xestochi ronomus from Costa Rica. Methods and Material The specimens were mounted on slides in Canada balsam following the procedure outlined by Saether (1969). The general terminology follows Saether (1980). The types are housed in the Museum of Zoology, University of Bergen, Norway (ZMBN); one male and one female paratype of X. aisenensis n. sp. are deposited in Museo Nacional de Historia Natural, Santiago, Chile. Xestochironomus aisenensis n. sp. (Figs. 1-11) diagnostic characters: The new species are assigned to the genus Xesto chironomus on the basis of having simple gonostylus and anal point with bulbous Accepted for publication 14 August 1997. This content downloaded from 157.55.39.59 on Sat, 15 Oct 2016 04:41:05 UTC All use subject to http://about.jstor.org/terms VOLUME 71, ISSUE 3 297 Figs. 1-6. Xestochironomus aisenensis n. sp., male imago. 1. Head. 2. Thorax. 3. Wing. 4. Left side of hypopygium, dorsal view. 5. Right side of hypopygium, ventral view. 6. Superior volsella. This content downloaded from 157.55.39.59 on Sat, 15 Oct 2016 04:41:05 UTC All use subject to http://about.jstor.org/terms 298 JOURNAL OF THE KANSAS ENTOMOLOGICAL SOCIETY or spatulate apex. It can be separated from X. ankylis Sublette and Sasa, 1994 and X. dominicanus Sublette and Wirth, 1972 by its larger size and by having an AR of 1.20-1.45, compared to AR < 0.90 in the former; from X. subletti Borkent, 1984 by having distinct, brown markings on thorax; and from X. brunneus Borkent, 1984 and X. latilobus Borkent, 1984 by lacking dark crossbands on the abdomen. description: Male imago (n = 11 except when otherwise stated). Total length 3.90-5.19, 4.68 mm. Wing length 2.16-2.88, 2.59 mm. Total length / wing length 1.73-2.01, 1.81. Wing length/length of profemur 2.37-2.59, 2.44. Coloration: tho rax with vittae, postnotum, anterior part of median anepisternum, and ventral por tion of preepisternum brown; legs pale brown, foreleg with apical 1/3 of femur, tibia, and tarsi brown; abdomen pale. Head (Fig. 1): AR 1.20-1.45, 1.36. Thirteenth flagellomere 582-812, 724 urn long. Temporal setae 12-16, 15 (7) in single row; including 5-6, 6 inner verticals; 4-7, 6 outer verticals; and 2-4, 3 postorbitals. Clypeus with 14-21, 17 setae. Ten torium 116-156, 136 |im long; 38-48, 44 |xm wide at sieve pore; 16-22, 19 |xm wide at posterior tentorial pit. Stipes 128-192, 167 ixm long; 8-16, 12 jum (9) wide. Palp segment lengths (in um): 36-48, 41; 48-96, 79; 160-232, 194 (10); 136-180, 156 (9); 208-280, 233 (7). Third palpal segment with 3-8, 6 lanceolate sensilla clavata; 22-26 urn long. Thorax (Fig. 2): Acrostichals 10-22, 17; dorsocentrals 12-24, 19 in single row; pre alars 5-9, 6. Scutellum with 11-16, 13 (10) large setae; 7-20, 12 (10) smaller setae. Wing (Fig. 3): VR 1.15-1.20, 1.18. Brachiolum with 2-4, 3 setae; R with 29-49, 39; R, with 34-66, 48; R4+5 with 34-11, 82; M with 0-4, 1 setae; remaining veins bare. Squama with 6-14, 10 setae. Legs: Spurs of middle tibia including comb 33-41, 36 |Lim (8) long and 29-41, 34 (im (8) long; of hind tibia including comb 37-49, 42 |im long and 23-31, 26 UMn long. Comb of mid tibia 14-18, 16 Jim long; comb of hind tibia 14-18, 17 |im long. Width at apex of front tibia 49-66, 55 |im; of middle tibia 49-70, 61 |xm; of hind tibia 49-74, 66 jum. Lengths (in |im) and proportions of legs (n = 7-11): fe ti ta, ta2 p, 940-1160, 1080 880-1100, 108
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