Taczanowskia gustavoi Ibarra-Núñez, 2013, new species
Creators: name: Ibarra-Núñez, Guillermo
Publisher: name: Zenodo
Year: 2013
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Arachnida
Araneae
Araneidae
Taczanowskia
Taczanowskia gustavoi

description: Taczanowskia gustavoi new species
Figures 1–12
Type material. Holotype: female from Finca Irlanda, Municipio Tapachula, Chiapas, Mexico (15º 10’ 11” N, 92º 20’ 38” W, 1,025 m altitude), 25 August 2011, G. López-Bautista (ECOTAAR-007756). Paratype: female from Rancho San Angel, Municipio Tuxtla Chico, Chiapas, Mexico (14º 55’ 47” N, 92º 09’ 43” W, 300 m altitude), 21 January 2012, G. López-Bautista (ECOTAAR-007757).
Etymology. This species is named in honor of the collector, Gustavo López-Bautista.
Diagnosis. The female of T. gustavoi differs from all others species in the genus by having a high but variable number of dorsal tubercles on the opisthosoma (34 and 29 in the two known specimens), as opposed to six or less dorsal tubercles in the other species. The two anterior rounded projections of the opisthosoma overhang almost half of the carapace, whereas in the other species these projections overhang only the posterior border. T. gustavoi has a row of dark spines along the ventral side of the first to third femora, in contrast to the other species with rows of spines only on the femora I and II. The soft epigynum has a very short and whitish translucent laminar scape, visible only as a terminal wide pocket, folded over its own base. This scape is much shorter than in the other species illustrated in Levi (1996). The female of T. gustavoi is larger than that of T. sextuberculata and T. striata, but smaller than T. mirabilis. Also its opisthosoma appears proportionally less wide than that of the other species. T. gustavoi is most similar to T. sextuberculata with which it shares: a) more than two dorsal tubercles on the opisthosoma, b) the shape of the tubercles on the opisthosoma (nipple-like, compare Figs. 2–3 with fig. 12); c) the shape of the epigynal openings in posterior view (slits, compare Fig. 11 with fig. 11).
Description. Holotype (female). Prosoma: cephalon coral-pink, thoracic area with some reddish-brown areas bordered with black bands, two white diagonal bands on each side, short sparse black setae over almost the whole carapace with some white setae on white or creamy-white areas, cephalon much narrower than thoracic area (Figs. 1, 2, 6). Chelicerae, labium, endites, sternum, coxae and trochanters coral-pink (Figs. 2, 4, 7); chelicera with two promarginal teeth and without teeth on retromargin; sternum shield-shaped, longer than wide, widest at coxae II, with a diffuse dark gray area in front of labium, on each anterior corner and as a longitudinal band between posterior coxae (Fig. 7); palpal femora coral-pink, reddish-brown on dorsal side, patellae to tarsi yellow with some coral-pink on venter side of tibiae (Figs. 1, 2, 6, 7). Most of the proximal part of the leg’s femora also coral-pink, darker on the legs I and II, yellow from the distal part of the femora to the tarsi, with some coral-pink spots on patellae and tibiae of the forelegs and on the venter of tibiae III and IV (Figs. 1–4, 8, 9). Femora of the first two pairs of legs thicker than those of femora III and IV (Figs. 1, 4); dorsum of femora I granulated and with black pigment (Figs. 3, 8); with a single row of dark spines along the ventral side of femora I to III, facing patella-tibia (Figs. 8, 9); the retrolateral claw of the first two pairs of legs about twice as long as the prolateral claw (Fig. 5). Opisthosoma: overhanging near half of carapace, almost circular in dorsal view, but slightly wider than long (1.3 times as wide as long in the midline), with two anterior rounded projections, giving the anterior margin an M shape in dorsal view (Figs. 1, 6). Dorsum with numerous yellow and white spots, almost contiguous and irregular (in size and form), with some black pigment among them; with 34 conical tubercles of different sizes, not symmetrically distributed between sides, covering most of dorsal opisthosoma, except anterior projections and middle surface between the sigilla (Figs. 1–3, 6); without feather-shaped setae. Sides of opisthosoma almost vertical, with anterior and anterolateral sides having the same color pattern as the dorsum, posterolateral and rear sides orange with vertical wide white bars surrounded with a thin black border and with a dark gray vertical band in the center of each (Figs. 2, 3). Venter fuchsia, except spinnerets and book-lungs covers which are white-fuchsia (Figs. 4, 9). The epigynum is on a transverse ridge in front of the epigastric furrow, with a very short, whitish translucent, soft scape, barely visible in form of a wide pocket just anterior to the epigynal openings (Fig. 10), the scape is similar in shape to that of Celaenia excavata (L. Koch, 1867), but smaller and not sclerotized as in that species (Levi 1996 figs. 25- 26, Levi 2003 table 2); in posterior view the epigynal openings look like two longitudinal slits (Fig. 11), similar to those of T. sextuberculata (Levi 1996 fig.11), with a slightly sclerotized plate between. The cleared epigynum shows two spherical spermathecae situated dorsal to the epigynal slits, with very short copulatory ducts. A fertilization duct arises from each spermatheca next to the copulatory duct, tapering and ending at the border of the genital opening (Fig. 12).
Measurements of holotype: total length 6.7; carapace 3.0 long, 3.5 maximum wide in thoracic region, 1.0 wide behind PLE. Diameter of AME 0.1, PME 0.8 diameter of an AME, laterals 0.7 diameter, AME 1.7 diameters apart, ALE 1.7 diameters from the AME, PME 1.6 diameters apart, PLE 2.4 diameters from the PME, ocular quadrangle as wide behind as in front; clypeus height 2.3 diameters of AME. Leg measurements (leg number: femur, patella, tibia, metatarsus, tarsus): I: 4.3, 2.0, 2.5, 1.3, 0.7; II: 4.3, 1.8, 2.5, 1.3, 0.7; III: 2.5, 1.0, 1.5, 1.0, 0.5; IV: 3.3, 1.3, 2.1, 1.3, 0.6. Opisthosoma length (in the middle) 4.3, maximum width 5.7; ratio width:length 1.3.
Variation (Paratype). Same color pattern as holotype, structure also similar, except that paratype has 29 conical tubercles on the dorsum of opisthosoma. Measurements: total length 6.9; carapace 2.8 long, 2.9 maximum wide in thoracic region, 0.9 wide behind PLE. Diameter of AME 0.1, PME 1.0 diameter of an AME, laterals 0.8 diameter, AME 1.6 diameters apart, ALE 1.6 diameters from the AME, PME 1.4 diameters apart, PLE 2.0 diameters from the PME, ocular quadrangle as wide behind as in front; clypeus height 2.0 diameters of AME. Leg measurements (leg number: femur, patella, tibia, metatarsus, tarsus): I: 3.7, 1.7, 2.1, 1.2, 0.6; II: 3.8, 1.8, 2.2, 1.2, 0.6; III: 2.2, 0.9, 1.3, 0.9, 0.4; IV: 2.7, 1.2, 1.8, 1.3, 0.5. Opisthosoma length (in the middle) 4.4, maximum width 5.7; ratio width:length 1.3.
Male: unknown.
Natural history. The coffee bushes (less than 2 m high) of the coffee plantation Finca Irlanda (the holotype’s locality) were subject to extensive collecting during almost 18 years, therefore it is surprising that T. gustavoi was found only recently. The holotype of T. gustavoi was found resting on the underside of a coffee leaf one and a half meter above ground. For the other Taczanowskia species there is no information on microhabitat or height at which they were collected, except for T. sextuberculata (Eberhard 1981), collected 1 m above soil among leaves of a guava tree (Psidium sp.) in Colombia, a similar height as the T. gustavoi holotype. However, the paratype of T. gustavoi was collected in a small mixed orchard (with fruit trees, but no coffee bushes, 32 km from Finca Irlanda) from a silk line descending from the canopy (about 8 m) of a Byrsonima crassifolia (Malpighiaceae) tree, seemingly in response to a smoke’s column from a small fire just below (G. López Bautista pers.com.). The finding of two specimens within an interval of five months and at different elevations (1,025 and 300 m altitude) indicates that T. gustavoi is not so rare in this region, but its presence as adults is probably limited to the rainy season.
This information suggests that T. gustavoi could live in the tree canopy, where methods such as fogging (not implemented) would be necessary to collect more specimens. It is possible that the holotype was found on a coffee bush as a consequence of a recent trimming or cutting of the shade trees in the coffee plantation, a management practice that has been more frequent in Finca Irlanda during the past four years. Therefore, it is not possible to know which are the microhabitat preferences of these species, but if the higher canopy preference is common, this could explain partially the scarcity of Taczanowskia specimens in collections, as the sampling of spiders in the higher canopy of trees is not a common practice. Thus, it would be necessary to include fogging in future spider studies at the sites where the types were collected, to test whether T. gustavoi is more a canopy resident or lives indistinctly at understory and canopy strata.
Distribution. Known only from Chiapas, Mexico.
description: Published as part of Ibarra-Núñez, Guillermo, 2013, A new species of the spider genus Tac zan o ws kia (Araneae, Araneidae) from Mexico, pp. 57-62 in Zootaxa 3664 (1) on pages 58-61, DOI: 10.11646/zootaxa.3664.1.3, http://zenodo.org/record/283814