Alpaida imperialis, Baptista & Castanheira & Prado, 2018

Baptista, Renner Luiz Cerqueira, Castanheira, Pedro De Souza & Prado, André Wanderley Do, 2018, Notes on the orb-weaving spider genus Alpaida (Araneae, Araneidae) with description of four new species from Rio de Janeiro, Brazil, Zootaxa 4407 (3), pp. 321-345 : 326-329

Alpaida imperialis new species

( Figs. 3–4 , Map 1)

Type-material. Holotype ♂. BRAZIL, Rio de Janeiro : Mendes: Centro Marista São José das Paineiras ( Sede ) 22° 30’ 35.1” S, 043° 45’ 16.5” W, 551 m, 25.II.2015, looking down, R. Baptista coll. ( MNRJ 7468 ) . Paratypes: BRAZIL, Rio de Janeiro : Mendes: Centro Marista São José das Paineiras ( Cruzeiro trail) 22° 30’ 41.8” S, 043° 45’ 41.7” W, 652 m, 17.XI.2014, looking down, R. Baptista coll., 1 ♀ ( UFRJ 1421 ) ; 24.VIII.2014, litter sieving, A. do Prado coll., 1 ♂ (UFRJ 1422); 26.II.2015, looking down, A. do Prado coll., 1 ♀ (MNRJ 7469); idem, Centro Marista São José das Paineiras ( Sede ) 22° 30’ 35.1” S, 043° 45’ 16.5” W, 551 m, 25.II.2015, looking down, R. Baptista coll., 2 ♀ ( MNRJ 7470 ) ; Rio de Janeiro : Parque Estadual da Pedra Branca, Camorim ( Açude trail) 22° 58’ 08.3” S, 43° 26’ 38.5” W, 342 m, 14.IX.2013, cryptic, R. Baptista coll., 2 ♀ ( MNRJ 7471 ) .

Additional material examined. BRAZIL, Rio de Janeiro : Mendes: Fazenda Arvoredo ( Encruzilhada ) 22° 30’ 16.8” S, 043° 45’ 34.6” W, 510 m, 16.XI.2014, looking down, R. Baptista coll., 1 ♀, 1 immature ( UFRJ 1425 ) ; Rio de Janeiro : Parque Estadual da Pedra Branca, Pau-da-fome ( Padaria trail) 22° 56’ 12.8” S, 043° 26’ 29.1” W, 133 m, 22.IX.2013, looking down, R. Baptista coll., 1 ♀ ( UFRJ 1426 ) ; 17.XII.2013, cryptic, R. Baptista coll., 1 ♀ (UFRJ 1427); 16.III.2014, looking down, R. Baptista coll., 1 ♀ (UFRJ 1428); idem, Parque Estadual da Pedra Branca, Camorim ( Açude trail) 22°58’08.3”S, 43°26’38.5”W, 342 m, 14.IX.2013, looking down, R. Baptista coll., 1 ♀ ( UFRJ 1429 ) .

Etymology. The specific epithet “ imperialis ” is a Latin word meaning “from emperor”. It is a reference to the Pedro II Railway, a railroad that connects the cities of Rio de Janeiro and Mendes and is named after Pedro II (1825–1891), last emperor of Brazil.

Diagnosis. Among closely related species, Alpaida imperialis new species seems to be most similar to Alpaida imperatrix new species (see diagnosis of the latter species above for details), but it differs by the absence of a contrasting medial sternal patch, and the epigynum almost rectangular, normally with a smaller notch, and less roundish lips, evidently excavated near the scape and wider at its median portion, which is projected over the sides of the posterior plate ( Fig. 4C–E ). Also, the palp of A. imperialis new species is diagnosed by its terminal apophysis much wider than long, with a median crest (instead of a tooth) and larger and inward bent distal lobe ( Fig. 3C ), a longer and acute tegular lobe, the wider and less slanted embolus and median apophysis longer and thinner ( Fig. 3C ), much shorter in ventral view ( Fig. 3D ).

Description. Male (holotype). Carapace, endites, sternum and chelicerae beige. Carapace with a wide median dark-brown stripe from eyes to pedicel, a bit thinner after the fovea ( Fig. 3A ). Eyes placed in anterior black patch ( Fig. 3A ). Chelicerae with paturon covered by black patches over most of its length and with reddish brown fangs. Endites also with black patches at its external side. Sternum beige, with brown margins. Legs pale beige with black patches on basal articles, darker on articulations ( Fig. 3A–B ). Abdomen cylindrical, longer than wide. Abdomen black with some beige spots and white cardiac area ( Fig. 3A ), sidescovered in black, with a median interrupted beige stripe on its first and second thirds, and venter beige, with a pair of transversal thin black stripes over the book-lung openings, a large black patch on its middle third and another one at its posterior margin. Spinnerets beige with a basal black patch. Palp with huge terminal apophysis, much wider than long, bearing a median crest and robust distal lobe, with its tip projected inward; embolus wide, elongated and blade-shaped, slightly slanted ( Figs. 3C ); median apophysis crescent-shaped, around three times longer than wide, also projected inward ( Figs. 3C ); tegular lobe thin and long, laterally projected ( Figs. 3C ). Paracymbium short, hooked ( Fig. 3D–E ). Total length: 3.82. Carapace: 2.14 long, 1.62 wide. Leg I: femur 1.79, patella 0.60, tibia 1.40, metatarsus 1.10 and tarsus 0.59. Patella + tibia II 1.50; III 1.35; IV 1.78.

Female (paratype UFRJ 1421). Carapace and endites light yellow. Carapace with a wide median light-brown stripe from eyes to fovea ( Fig. 4A ). Eyes, sternum and legs as in male. Chelicerae with brown paturon and reddish brown fangs. Abdomen elongated, roundish at sides and with a posterior acute tip ( Fig. 4B ). Dorsum greyish, with white cardiac area, sided by a pair of dark grey patches, followed by a pair of U shaped dark grey streaks on the middle third and a big dark grey area on the posterior third ( Fig. 4A ). Sides covered in black with a median interrupted brown stripe. Venter grey, with abundant guanine dots forming a white contour ( Fig. 4B ). Spinnerets light brown with basal dark grey spots. Epigynum rectangular, much wider than long, with large and protruding rounded lips, excavated around the short scape, much lighter than surrounding areas ( Fig. 4C–D ). Posterior plate high, but still wider that high, and slightly depressed in both sides, with lips projected over it at its middle portion ( Fig. 4E ). Total length: 4.75. Carapace: 1.75 long, 1.51 wide. Leg I: femur 1.26, patella 0.69, tibia 1.20, metatarsus 1.12 and tarsus 0.50. Patella + tibia II 1.73; III 1.24; IV 1.74.

Variation. Males (n = 2): total length, 3,82–4.00; females (n = 11): total length, 3.72–5.34. Endites may vary in colour strength among specimens. Female abdomen can be darker, with black patches more strongly marked, reducing its greyish area. The amount of guanine in venter is variable among specimens of both sexes. Living specimens tend to be darker too. Epigynal notch can be rounded and not as pointed as described (e. g. UFRJ 1429).

Natural History. Alpaida imperialis new species can be found in habitats very alike Alpaida imperatrix new species. It was collected near ground by “sieving” litter, searching “cryptic” habitats and using “looking down” sampling techniques. During night, the small vertical orb-webs were easily spotted near rotten logs and large tree roots. The spider was usually crouched at some crevice on the wood surface, holding a signal line connected to the web hub. Sometimes, their webs were placed near the much larger webs of A. tijuca .

Distribution. Only know from Mendes and Rio de Janeiro cities, at Rio de Janeiro state, Brazil (Map 1).

Figures

FIGURE 4. Alpaida imperialis new species female paratype (UFRJ 1421): A, dorsal habitus. B, ventral habitus. C–E, epigynum views; C, ventral.D, frontal.E, posterior.Scale bars, A, B, 2 mm; C, D, 0.2 mm.

FIGURE3. Alpaida imperialisnew species maleholotype:A, dorsal habitus.B, ventral habitus.C–E,left male palp; C, mesal. D, ventral. E, ectal.Abbreviations, D, distal lobe; Cr, crest. Scale bars, A, B, 2 mm; C, D, E, 0.2 mm.