Aculepeira morenoae, Rubio, Gonzalo D., Izquierdo, Matías A. & Piacentini, Luis N., 2013

Rubio, Gonzalo D., Izquierdo, Matías A. & Piacentini, Luis N., 2013, A new orb-weaving spider from the Argentinean flooding pampas grasses: Aculepeira morenoae new species (Araneae, Araneidae), Zootaxa 3613 (6), pp. 548-556 : 549-552

Aculepeira morenoae new species

( Figs 1–32 )

Type material. Holotype female (MACN-Ar 28655; temporary preparation GDR-0245) from Campos del Tuyú National Park (36º21´24.3˝S, 56º51´38.7˝W, 5m. a.s.l.), General Lavalle, Buenos Aires Province, ARGENTINA, 24–26 March 2012, G. Rubio, L. Piacentini and M. Izquierdo coll. Paratypes: same data, one male (MACN-Ar 28656; temporary preparation GDR-0244), one male (MACN-Ar 28657; temporary preparation GDR-0242), one female (MACN-Ar 28658; temporary preparation GDR-0247, LNP-4192[tissue sample]), one female and two immatures (MACN-Ar 28659; temporary preparation GDR-0243).

Note. The female was selected as holotype because in the revisions of American Aculepeira the 86% of species have female holotypes, and the greatest diversity of shapes is illustrated in the epigyna (see Levi 1991), thus provides more accurate diagnostic comparisons than males.

Etymology. The specific name is a patronymic in honor to Dr. Claudia E. Moreno, ecologist of Universidad Autónoma del Estado de Hidalgo, Mexico.

Diagnosis. Female and male of A. morenoae n. sp. ( Figs 1–4 , 7–9 ) resembles A. albovittata in having an elongate abdomen and a triangle-shaped scape (Levi 1991: figs 560, 562), and a sickle-shaped terminal apophysis respectively (Levi 1991: figs 563) ( Figs 14 , 16–22 , 27 ); also, male resembles A. angeloi Álvares, Loyola & De Maria 2005 by having median apophysis with a similar dentate structure in its retrolateral end (Álvares et al. 2005: fig 1) ( Figs 14–20 , 28–30 ). Aculepeira morenoae n. sp. can be easily distinguished from similar species by having a uniform colored abdomen in dorsal view (present in both sexes, figures 1, 3), scape ending gradually toward a shorter tip (long in A. albovittata ) ( Figs 7–9 ), lateral plates converging dorsally on the median plate (a different shaped and not convergent in A. albovittata ) (figure 10; compare with fig 561 –Levi 1991), males with irregular rows of 9–12 strong spines in prolateral side of femur I (six in A. albovittata ) ( Figs 3 , 6 ), and by a particular arrangement of six (three large and three small) teeth on the retrolateral side of median apophysis ( Figs 26–30 ).

Description. Female (holotype): Carapace yellowish, with a blackish longitudinal strip starting near the posterior eyes towards the thoracic groove ( Figs 1 , 5 ). Four to six setae behind lateral eyes. Eye sizes and interdistances: anterior median eye (AME) 0.14, anterior lateral eye (ALE) 0.10, posterior median eye (PME) 0.12, posterior lateral eye (PLE) 0.09, AME-PME 0.23, AME-ALE 0.42, AME-PLE 0.57, PME-ALE 0.54, PME-PLE 0.55, ALE-PLE 0.07. Chelicerae pale yellow with four smaller retromarginal teeth and four larger promarginal teeth ( Figs 2 , 5 ); sternum with irregular dark spots, coxae light yellow ( Fig 2 ). Legs pale yellow. Tibia and metatarsus I-IV with macrosetae. Abdomen elongate oval, pale yellow dorsally with four black spots forming a square, and irregularly distributed guanine dots ( Fig 1 ). Venter of abdomen with a median dark brown band slightly bordered by a white strip on each side, spinnerets brown, and the rest of venter pale yellow, without median white band ( Fig 2 ). Epigynum ( Figs 7–10 ) with triangular scape, pointed at tip; median plate wider than long; lateral plate converging dorsally on the median plate; spermathecae spherical; fertilization ducts relatively straight, dorsally directed; copulatory ducts in ventral posterior position with spermathecae ( Fig 11–12 ). Total length 11.18; carapace length 4.55, width 3.22; sternum length 2.24, width 1.54; abdomen length 7.80, width 4.20. Leg formula I/II/IV/III. Leg lengths (I/II/III/IV): femur 4.58/4.55/3.15/4.06; patella 2.10/2.03/1.33/1.75; tibia 4.83/4.35/2.10/3.81; metatarsus 4.55/3.85/2.06/3.71; tarsus 1.78/1.61/0.98/1.09; total leg 17.84/16.39/9.62/14.42.

Male (paratype MACN-Ar 28656): Coloration as in the female except as noted ( Figs 3–4 ). With some macrosetae instead setae (unlike the female) behind lateral eyes. Eye sizes and interdistances: AME 0.09, ALE 0.075, PME 0.09, PLE 0.075, AME-PME 0.21, AME-ALE 0.21, AME-PLE 0.33, PME-ALE 0.33, PME-PLE 0.33, ALE-PLE 0.06. Chelicerae with four small promarginal teeth. Coxa I without hook. Tibia and metatarsus I-IV with macrosetae. Ventral side of femur I with three approximately irregular rows of 9–12 strong spines. Abdomen shape and color as in the female, but ventrally more pigmented. Palp segments pale yellow, bulb gray to reddishyellow ( Figs 6 , 13–15 ); broad terminal apophysis, long embolus visible, membranous conductor; bilobed median aphophysis bearing two slender flagellae on its prolateral end, and six (three large and three small) teeth on retrolateral side ( Figs 13–30 ). Total length 7.00; carapace length 3.15, width 2.26; sternum length 1.24, width 0.81; abdomen length 4.13, width 2.17. Leg formula as in the female. Leg lengths (I/II/III/IV): femur 3.99/3.57/2.38/ 2.87; patella 1.40/1.40/0.70/1.05; tibia 3.57/3.01/1.50/2.59; metatarsus 3.85/2.87/1.40/2.73; tarsus 1.54/1.12/0.77/ 0.91; total leg 14.35/11.97/6.75/10.15.

Variation. Females: total length 9.49–11.18; carapace length 4.06–4.55, width 2.73–3.22; abdomen length 6.65–7.80, width 3.08–4.20; one female has three teeth in retromargin of the chelicerae. Males: carapace width 2.20–2.26; abdomen length 4.13–4.27, width 2.10–2.17.

Natural history. These spiders build a complete orb-web at one meter height on the grasses, where they inhabit in sympatry with Larinia tucuman Harrod, Levi & Leibensperger 1991 . Periodically flooded areas in sectors near to the coastal lagoons are the natural habitat of A. morenoae , where the "espartillar" of Spartina densiflora , Sarcocornia perennis (“cangrejal”), and Cortaderia selloana (large pampa grass) are dominant ( Figs 31–32 ). The spiders were collected both during night and day resting at the hub of their webs.

Distribution. Only known from the type locality. No additional material was found in the MACN collection, despite having done extensive samplings in Buenos Aires province. A potential explanation for this may be offered by the reduced geographic range of the natural flooding pampas grasses (Bilenca & Miñarro 2004) where the specimens were found. A similar situation/distribution is observed and reported for the uloborid spider Sybota atlantica Grismado 2001 .

Material examined for comparison. Aculepeira albovittata (Mello-Leitão 1941: 214, f. 20) (Holotype female from ARGENTINA: Santa Fe, Caraguatay, November 1939, Birabén coll., deposited in the arachnid collection of Museo de La Plata—MLP 15150).

Figures

FIGURES 1 – 4. Aculepeira morenoae n. sp., habitus. 1 – 2, female holotype (1, dorsal; 2, ventral). 3 – 4, male paratype (3, dorsal; 4, ventral).

FIGURES 5 – 6. Aculepeira morenoae n. sp., frontal view. 5, female holotype. 6, male paratype.

FIGURES 7 – 12. Aculepeira morenoae n. sp., female genitalia. 7 – 9, epigynum (7, ventral; 8, lateral; 9, digested ventral). 10 – 12, digested vulva (10, posterior; 11, anterior; 12, dorsal).

FIGURES 13 – 15. Aculepeira morenoae n. sp., left palp. 13, prolateral; 14, ventral; 15, retrolateral. (c = conductor; cy = cymbium; e = embolus; ma = median apophysis; pc = paracymbium; sa = subterminal apophysis; ta = terminal apophysis; * = flagellae of ma; + = dentate end of ma). Scale bars: 0.2 mm.

FIGURES 16 – 23. Aculepeira morenoae n. sp., expanded left palp. 16 – 18, ventral from different angle; 19, prolateral; 20, retrolateral; 21, retrolateral-basal; 22, prolateral-apical; 23, apical. (bh = basal hematodocha; c = conductor; cy = cymbium; dh = distal hematodocha; e = embolus; f = fundus; ma = median apophysis; pc = paracymbium; r = radix; sa = subterminal apophysis; sd = sperm duct; t = tegulum; ta = terminal apophysis; * = flagellae of ma; + = dentate end of ma).

FIGURES 24 – 30. Aculepeira morenoae n. sp., left palp SEM. 24, retrolateral-ventral; 25, retrolateral; 26, dorsal; 27, apical; 28 – 30, close up views (28, median apophysis; 29 – 30, dentate end of median apophysis. (c = conductor; cy = cymbium; e = embolus; ma = median apophysis; pc = paracymbium; sa = subterminal apophysis; ta = terminal apophysis; * = flagellae of ma; + = dentate end of ma). Scale bars: 0.5 mm

FIGURES 31 – 32. Flooding pampas grasses in Campos del Tuyú National Park, Buenos Aires, habitat of Aculepeira morenoae n. sp. 31, panoramic view looking northeast; 32, grasses where spiders inhabit.