Dubiaranea difficilis (Mello-Leitão 1944)

Cajade, Manuel, Hagopián, Damián, Rodrigues, Everton N. L., Guerrero, José C., Laborda, Álvaro & Simó, Miguel, 2024, A new species and new records of the spider genus Dubiaranea (Araneae, Linyphiidae) from southern Brazil and Uruguay, with an analysis of the potential distribution of the species, Zootaxa 5437 (2), pp. 223-244 : 236-238

Dubiaranea difficilis (Mello-Leitão 1944)

Figs 8–11

New records. URUGUAY. Maldonado, Sierra de Carapé (34°31’25”S, 54°58’30.34”W), 15.xi.2019, M. Simó & Á. Laborda coll., 1F (FCE-Ar 10903); same data, 1F (FCE-Ar 10843) . Río Negro, El Matorral (33°01’12.1”S, 57°33’59.7”W), 27.xi.2019, M. Simó & Á. Laborda coll., 1F (FCE-Ar 12740). Ruta 24, km 85, Arroyo Negro, Estancia “Las Cadenas” (32°31’16.02”S, 58°2’7.03”W), 12–16.iii.2018, D. Hagopián & A. Mailhos coll., 1F (FCEAr 13602) . Durazno, Eucalyptus plantation, near La Paloma (32°32’40.52”S, 55°42’51.74”W), 26.viii.2021, D. Hagopián & M. Cajade coll., 2F (FCE-Ar 10282); same data, 1F (FCE-Ar 10374); (32°32’40.67”S, 55°42’43.55”W), 26.viii.2021, D. Hagopián coll. 1F (FCE-Ar 13546); same data, 1F (FCE-Ar 13605) . Rivera, Cerro Miriñaque (31°29’56.7”S, 55°38’59.9”W), 30.x.2010, M. Simó & Á. Laborda coll., 1M, 3F (FCE-Ar 4433). Ruta 27, Arroyo Batoví (31°06’58.5”S, 55°24’57.4”W), 30.x.2010, M. Simó coll., 1F (FCE-Ar 4068) .

Other records from GBIF. ARGENTINA. Buenos Aires. San Pedro. Parque Histórico Natural Vuelta de Obligado (33°35’53.89”S, 59°48’35.38”W). 1F (MACN-Ar 36853), 1F (MACN-Ar 36855), 1F (MACN-Ar 36862), 1F (MACN-Ar 36940), 1F (MACN-Ar 36942). San Isidro. Acassuso, Reserva Municipal Refugio Natural Educativo Ribera Norte (34°28’2.32”S, 58°29’37.21”W). 1F (MACN-Ar 32035), 1F (MACN-Ar 32424), 1F (MACN-Ar 33063), 1F (MACN-Ar 33325), 1F (MACN-Ar 33471), 1F (MACN-Ar 33563), 1F (MACN-Ar 34711). Reserva Ecológica Costanera Sur , CABA (34°36’16.7”S, 58°21’00.6”W), 11.xi.2021, L. Zapata, 1F (iNaturalist. https://inaturalist-open-data.s3.amazonaws.com/photos/169095457/original.jpg) . Entre Ríos. Parque Nacional Predelta, sendero a Laguna Las Piedras (32°7’28.79”S, 60°37’39.65”W) 1F (MACN-Ar 28317) . Jujuy. Ledesma. Parque Nacional Calilegua, Mesada de las Colmenas (23°39’54.06”S, 64°50’25.62”W). 1M (MACN-Ar 27126), 1M (MACN-Ar 27129), 1M (MACN-Ar 27130). Parque Nacional Calilegua, Alisal, km 21 Ruta Provincial Nº 83 (23°41’8.38”S, 64°53’2.61”W). 1M (MACN-Ar 27130) .

Natural history. In Uruguay, Dubiaranea difficilis ( Figs 8–9 ) was found in riparian native forests, hill native forests, grasslands and Eucalyptus dunnii Maiden forestry plantations (six and ten year old plantations) ( Fig. 10 ). This species has already been found for riparian forests ( Laborda et al. 2018) and ravine forests ( Laborda et al. 2020) from this country. In the forests they spin their web between branches of the undergrowth, in the Eucalyptus plantations between fallen branches on the ground near the base of the trees, and in the grasslands between subshrub vegetation and erect herbs. The webs of the females can reach 25 cm in length, males were found in smaller webs close to the webs of the females.

Distribution. Known for northern and Central Argentina and Uruguay ( Fig. 11 ). The model shows favourable areas for the species in Bolivia and southern Brazil. Seven predictor variables were selected for the model distribution of the species. Tree cover (12.472), Spatial component (Wald: 14.461), Precipitation in the warmest quarter (BIO 18) (Wald: 7.890), Summatory of Big rivers (Wald: 8.381) and Seasonal temperatures (BIO 4) (Wald: 10.432) had a positive relationship. Contrary, Evapotranspiration Potential Annual (ETP Annual) (Wald: 18.315) and Crops (Wald: 4.150) showed a negative relationship ( Table 2 ).

Figures

FIGURE 8. Dubiaranea difficilis, male from a Eucalyptus dunnii plantation in Durazno, Uruguay (photographed out of their environment). Habitus. A–B. A, lateral. B, dorsal.

FIGURE 9. Dubiaranea difficilis, female from a Eucalyptus dunnii plantation in Durazno, Uruguay (photographed out of their environment). Habitus. A–B. A, lateral. B, dorsal.

FIGURE 10. Some environments where Dubiaranea difficilis can be found in Uruguay. A–C. A, riparian native forest (Río Negro, Uruguay). B, Grasslands (Durazno, Uruguay). C, Eucalyptus dunnii plantations (Durazno, Uruguay).

FIGURE 11. Potential distribution of Dubiaranea difficilis obtained by the stepwise combined model using the Favourability Function. White circles represent D. difficilis previous records and sky blue circles new ones.