Alterosa, Blahnik Table Of Contents, 2005

Blahnik Table Of Contents, Roger J., 2005, Alterosa, a new caddisfly genus from Brazil (Trichoptera: Philopotamidae), Zootaxa 991 (1), pp. 1-60: 10-13

publication ID 10.11646/zootaxa.991.1.1

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scientific name


new genus

Alterosa   , new genus

Type species: Alterosa bocainae   , new species.

The single character most useful for diagnosing Alterosa   , and which may be uniquely apomorphic, is the structure of the phallobase of the male ( Figs. 6D View FIGURE 6 , 8D View FIGURE 8 , 9D View FIGURE 9 ), which is tubular basally and lacks the basodorsal expansion common in most philopotamids, including species in the subfamily Chimarrinae   . Other characters of the male genitalia useful, in combination, to diagnose the genus include: intermediate appendages positioned mesally to the preanal appendages ( Figs. 6A,B View FIGURE 6 ; 10A,B View FIGURE 10 ), absence of ventral processes on any of the terminal segments of the male genitalia, and sternum IX with the posteroventral margin distinctly produced and widely truncate ventrally ( Figs. 9A,B View FIGURE 9 ; 10A,B View FIGURE 10 ) and the posterodorsal margin acutely articulating with the tergum ( Figs. 6A View FIGURE 6 , 9A View FIGURE 9 ). Preanal appendages arise from the base of tergum X ( Fig. 6A View FIGURE 6 , 10A View FIGURE 10 ), rather than the dorsal margin of sternum IX (as is typical in Sortosa   , see Ross 1956, figs. 36A, 37A, 38A). In species in which the preanal appendages are not secondarily modified ( Fig. 9A View FIGURE 9 ), they are relatively simple in structure, elongate and finger­like ( Figs. 6A View FIGURE 6 , 11A View FIGURE 11 ). Venation ( Fig. 1 View FIGURE 1 ) is primitive for Philopotamidae   and very similar to Sortosa   and Hydrobiosella   . Female genitalia ( Fig. 4 View FIGURE 4 ), like those of most genera of Philopotaminae   , excluding Dolophilodes   , Fumonta   , and Philopotamus   , are elongate and tapered, with very long, articulated apodemes from the anterior margin of sternum VIII and tergum IX.

Adult. Color of pinned, dry specimens dark brown overall with contrasting small light brown or yellowish spots on forewings, these sometimes arranged in irregularly linear arrays near costal margins; legs, palps, and antennae usually paler in color. Three ocelli present, prominent. Eyes with short projecting setae between the ommatidia. Maxillary palps ( Fig. 2 View FIGURE 2 ) 5­segmented, relatively short: 1st segment very short, usually broadly joined (often apparently fused) to 2nd segment, usually with a few setae on apicomesal margin; 2nd segment short, globose, with numerous elongate setae on apicomesal surface; 3rd segment relatively short, about 3 or 4x length of segment 2; 4th segment very short, about 2x as long as wide; 5th segment longer than segment 3, variable in length among species. Setal warts of head (Fig. 3) well developed; posterolateral warts large, typical of Philopotamidae   ; posterior setal warts rounded, separated mesally; anteromesal setal wart large, subtriangular, notched mesally to accommodate anterior ocellus, laterally fused to anterior setal warts; fused anterior and anteromesal warts roughly M­shaped. Prothorax with rounded mesal setal warts, slightly separated mesally, laterally with indistinctly defined setal areas. Wing venation ( Fig. 1 View FIGURE 1 ) primitive (forewing with forks 1–5 present, hind wing with fork 4 missing, anal veins of hind wing reaching wing margin); fork 1 of forewing branching just proximal to discal crossvein; s, r­m, and m crossveins of forewing nearly linearly arranged, these plus m­cu, base of fork 3, and apex of Cu 2 clear, unpigmented. Spur formula 2:4:4.

Male Genitalia. At least some abdominal terga, through and including tergum VIII, with unpigmented spots surrounding elongate setae on posterior margins. Abdominal

sterna VII, VIII, and IX without ventromesal processes. Tergum VIII usually with distinct posteromesal invagination ( Fig. 11E View FIGURE 11 ), but sometimes absent or very weakly developed. Sternum IX with posteroventral margin greatly produced; as viewed ventrally, broadly truncate, usually with slight mesal invagination, with distinct mesal suture line extending from anterior to posterior margin; posterodorsal margin acutely articulated with tergum, and below dorsal development of tergum X. Tergum IX greatly reduced or fused to base of tergum X, sometimes developed into mesal or lateral projections extending over base of tergum X. Tergum X moderately to greatly elongate, entire, apically with numerous short sensilla. Intermediate appendage mesal to preanal appendage, very differently developed in different species, often with apical spines or setae. Preanal appendage inserted membranously or apparently partially fused to base of tergum X, elongate linear and basally constricted in most species, highly modified in shape, with apical armature of spines or setae in others. Inferior appendages elongate linear, with 2 articles, varying in relative length among species; apex of 2nd article with pad of short, stiff setae on mesal surface. Phallic apparatus with phallobase tubular, without basodorsal expansion, usually somewhat curved, sometimes distinctly bent; endotheca highly variable, usually with included spines, these varying greatly in size, number and position among different species; phallotremal sclerite usually small, weakly sclerotized and indistinct.

Female Genitalia. Genitalia ( Fig. 4 View FIGURE 4 ) elongate and tapered. Segment VII distinctly elongate, pleural region more or less pleated. Intersegmental region between segments VII and VIII membranous and relatively elongate. Segment VIII with tergum reduced, tapered posteriorly; sternum with elongate, rod­like, articulated apodemes from anterolateral margins. Segment IX reduced and tapered; tergum often more sclerotized along anterior and ventral margins, anterolaterally with elongate, rod­like, articulated apodemes; sternum less sclerotized, often nearly membranous. Segment X comprised of pair of bulbous, setose lobes, each terminating in short apical cercus. Vaginal apparatus usually membranous and often more or less indistinct, anteriorly with cupped sclerite. Etymology. Alterosa   is a name, feminine in gender, traditionally used to refer to the mountains of southern Minas Gerais, Brazil.