Anacroneuria tucuman Stark, 2013

Pessacq, Pablo & Marcela, De Paul, 2015, Description of the last instar larva of Anacroneuria tucuman Stark (Plecoptera: Perlidae) from northern Argentina, Zootaxa 4033 (2), pp. 270-274 : 271-273

Anacroneuria tucuman Stark, 2013 ( Figs. 1–8 )

Anacroneuria tucuman Stark, 2013: 97 , figs. 5-9 (male description, type locality: Horco Molle, Tucumán , Argentina; illustrations of head, sternum 9, and aedeagus in dorsal, lateral and ventral views).

Material studied. One adult male and five larvae (one pharate male, one final instar and three intermediate instars), Argentina, Jujuy Province, Lampazar River approximately 3 km south of Guerrero, 24° 12´48,8” S, 65° 26¨45,2” W, 1629 masl, 27.x.2011, M. De Paul leg. Two larva of intermediate instars, same data as previous but Quesera River, 20° 12´48,5” S, 65° 26´, 40,7” W, 1621 masl, 8.xi.2010.

Last instar larva description. Dorsum of head ( Fig. 1 ) with a trapezoidal brown area, narrower posteriorly and extending from the ocelli to posterior margin of clypeus; its apical margin with two transverse and long triangular dark brown areas. Clypeus and remainder of head yellow. Mandible ( Fig. 4 ) with five teeth, a row of short thin bristles on dorsal surface close to inner margin and a ventral row of long bristles on ventral surface also close to inner margin. Laciniae ( Fig. 3 ) with a row of nine long bristles on its inner margin basal to apical hooks. Pronotum ( Fig. 1 ) yellow, with lighter scattered areas on its median region, meso- and metanotum light brown with lighter oval medial areas. Fore femur ( Fig. 2 ) with a well-developed dorsal fringe extending from base of medial third to apex; with an oblique row of bristles between basal and medial third, bristles gradually longer towards dorsal margin; with several scattered long and short bristles distal to the oblique row and several short bristles close to the ventral margin; a row of five short bristles in the apical margin. Femoral surface covered by clothing hairs, except a median elongated area and a patch basal to the oblique row of bristles. Mid and hind femora same as forefemur, except for the oblique row of bristles, located on basal third on mid femur and absent in hind femur. Tibiae ( Fig. 2 ) with a well-developed dorsal fringe; a row of long bristles on its dorsal margin, two rows of short bristles on its ventral margin and several thick bristles on its apex. Apices of tarsi with several long and straight bristles. Abdominal terga light brown, sterna whitish, posterior margin with a row of short bristles ( Fig. 6 ). Basal cercomeres with a few short bristles ( Fig. 6 ) increasing in number towards apex ( Figs. 7–8 ).

Measurements (in mm, n: 1): body length without cerci 10.8; head length 2.05; head width 2.75; pronotum length 1.55; pronotum width 2.85.

Distribution. This species has been previously recorded from the Yungas Rainforest of Tucumán Province, Argentina by Stark (2013). This is the first record of the species for Jujuy Province, also in the Yungas Rainforest, located approximately 400 km north of Tucumán .

Ecological comments. Hydrological and physicochemical characteristics of the sites are described in Tables 1 and 2 . This study was part of a larger project including ecological studies of the Reyes River Basin. This study indicated that aquatic insect abundance in the Lampazar and Quesera rivers were higher than those of other streams of the Basin. This may be related to the fact that these rivers have relatively low anthropic impacts and still have well-developed riparian vegetation. The streams have low salinity, conductivity, and suspended solids. Assemblages with other species in the community of Reyes Basin was tested using Spearman correlation, significant associations values (p <0.05) ( Elliot, 1977) were found with Mortoniella sp., Metrichia sp., Ochrotrichia sp., Nectopsyche sp., Helicopsyche sp. ( Trichoptera ); Corydalus sp. ( Megaloptera ); Athericidae sp., Psychodidae sp., Tipulidae sp. ( Diptera ); Austrelmis sp., Neoelmis sp., Psephenus sp. ( Coleoptera ); Microvelia hungerfordi McKinstry , Eurygerris fuscinervis (Berg) , ( Hemiptera ); Coleophora sp. ( Lepidoptera ).

Notes. An adult male of A. tucuman and two last instar larva (one pharate male) were collected in the same day and locality, the specific identification of the larva herein described was confirmed by dissection of genitalia of the pharate male. On the same day and locality another species of Anacroneuria was also collected from the Quesera and Lampazar rivers, but was much larger species.

Stream Season pH Temperature °C Conductivity Total solids NaCl (ppm) Dissolved ( uS) dissolved (mg/L) oxigen (mg/L)

Figures

FIGURES 1 – 2. Anacroneuria tucuman Stark larva. 1: head and pronotum, dorsal view. 2: fore leg, dorsal view.

FIGURES 3 – 5. Anacroneuria tucuman Stark larva. 3: left maxilary palp, laciniae and galea, ventral view. 4: right mandible, dorsal view. 5: labium, ventral view.

FIGURES 6 – 8. Anacroneuria tucuman Stark larva. 6: abdominal segments 9 – 10, dorsal view. 7: cercomeres 14 – 17. 8: cercomeres 24 – 26.