Myrmecotypus haddadi, Perger & Rubio, 2021

Perger, Robert & Rubio, Gonzalo D., 2021, Myrmecotypus haddadi sp. nov. - a new species of ant resembling sac spider from the Bolivian orocline (Araneae: Corinnidae: Castianeirinae), Zootaxa 4969 (1), pp. 54-60 : 56-59

publication ID	https://doi.org/ 10.11646/zootaxa.4969.1.2
publication LSID	lsid:zoobank.org:pub:57DCEB7B-B7DD-41BF-AECE-AD757C988EAC
DOI	https://doi.org/10.5281/zenodo.4813076
persistent identifier	https://treatment.plazi.org/id/16B033D9-2AC3-415D-8741-B32C349CF7F0
taxon LSID	lsid:zoobank.org:act:16B033D9-2AC3-415D-8741-B32C349CF7F0
treatment provided by	Plazi
scientific name	Myrmecotypus haddadi
status	sp. nov.

Treatment

Myrmecotypus haddadi View in CoL sp. nov.

(LSID: urn:lsid:zoobank.org:act:16B033D9-2AC3-415D-8741-B32C349CF7F0 )

Figs 2 View FIGURE 2 , 3 View FIGURE 3 , 4 View FIGURE 4 .

Type material. Holotype ♂ from BOLIVIA: Santa Cruz department, Santa Cruz de la Colina, Urubo (-17.760833°; -63.24°), 432 m a.s.l., 21 Dec 2019, leg. R. Perger, Cerrado-like grassland adjacent to fragment of Chiquitano forest ( ZMH-A0015356 ) . Paratypes: 1 ♂, same data as holotype ( ZMH-A0015357 ) . 1 ♂, 1 ♀, Santa Maria la Antigua (- 17.3719°; -63.6563°), Cerradao, ~ 30 m away from Cerrado savanna, 13 Apr 2018, leg. R . Perger (IBSI-Ara1463).

Etymology. The specific epithet, haddadi , is a patronym in honour of Charles R. Haddad in recognition of his contributions to the taxonomy of Castianeirinae .

Diagnosis. Judging from the light coxa II and the remainder of coxae dark ( Figs 2 View FIGURE 2 ; 4B View FIGURE 4 ), the tibia I ventral spination 3-3 and the male genital bulb with two loops lateral to main sperm duct ( Fig. 3 View FIGURE 3 A-C), the species is most closely related to M. iguazu Rubio & Arbino, 2009 , M. rubrofemoratus Perger & Rubio, 2021 and M. tahyinandu Perger & Rubio, 2020 (this combination of characters is not found in other congeners). Myrmecotypus haddadi sp. nov. can be separated from these species by a broader carapace in relation to the carapace length (carapace index of 57 in male and 54 in female) and the cephalic width (cephalic index of 67 in male and 70 in female) ( Figs 2A View FIGURE 2 , 4A, C View FIGURE 4 ); embolus of male palp cat claw-shaped, forming beak-like structure with a spatula-shaped tegular projection (coupling piece) ( Fig. 3A, B View FIGURE 3 ), epigyne with two widely separated, rounded genital openings mediolateral to spermathecae ( Fig. 3D, E View FIGURE 3 ) (see Tab. 1 View TABLE 1 for comparisons).

Remarks. Rubio & Arbino (2009) and Perger & Rubio (2020a) hypothesized that some Neotropical species of Apochinomma Pavesi, 1881 may belong to Myrmecotypus . Amongst those species, A. formicoides Mello-Leitão, 1939 , is the only with a sub-globose abdomen and light coxa II (the remainder of coxae dark) ( Mello-Leitão 1939). This species can be distinguished from M. haddadi sp. nov. by a carapace index of 41 and the distance between the inner margins of the PLE being as wide as the maximum width of the AER ( Mello-Leitão 1939) (wider in the new species).

Description of male holotype. Body length 5.23; carapace length 2.79, width 1.58, carapace index 57; cephalic width 1.09, cephalic index 67; sternum length 1.28, width 0.93, sternum index 72; abdomen length 2.21, width 1.62, abdominal index 73; petiole length 0.09, width 0.38; dorsal sclerite length 2.21, width 1.62; epigastric sclerite length 0.63, width 1.07; ventral sclerite length 0.95, width 0.73; inframamillary sclerite length 0.23, width 0.56. AER 0.64; AME–AME 0.09; AME–ALE 0.04; PER 0.91; PME–PME 0.24; PME–PLE 0.17.

Carapace ( Fig. 2A, C View FIGURE 2 ). Obovate, squarely truncated anteriorly, front slightly convex, cephalic region narrowed, laterally slightly concave, thoracic region distinctly broadening in middle, evenly narrowing in posterior direction, posterior margin straight; slight constriction between cephalic and thoracic regions and posterior region strongly convex when viewed laterally. Dorsum weakly shiny, smooth, dark brown; setae short, appressed, white, simple, relatively dense laterally between cephalic and thoracic regions but not obscuring integument (setae mostly abraded after storage in ethanol).

Eyes. Eight eyes in two rows; both slightly recurved, diameter of AME about 30% larger than that of other eyes.

Chelicerae. Orange brown, shiny, glabrous, area between retro- and promarginal rows of cheliceral teeth orange white with dense white hairs, 2 retro- and 2 promarginal teeth.

Abdomen. Short oval; anterior margin of petiole straight; dorsal sclerite completely covering abdomen dorsally and laterally; ventral sclerite fully developed, covering area between ventro-lateral margins of dorsal scutum and between epigastric and inframamillary sclerites; inframamillary sclerite narrow, subrectangular. Dorsum weakly shiny, smooth, dark brown; abdominal setae long, simple, not sclerotized to spines, dark; simple, short, white setae on abdomen; transverse band of feathery setae in middle; separate, long, erected white setae on posterior part (most setae strongly abraded).

Legs. Coxa II translucent white, remainder of coxae dark brown, trochanters I-IV whitish-yellow; femora I and II translucent white, broad black bands along edges, remainder of leg I and II yellow; femora and tibiae III and IV dark brown, edges lined with bands of short, appressed, white feathery setae, base patella IV translucent white ventrally, metatarsi and tarsi III and IV light brown.

Palp. Margin of pedipalp tibia continuous; tarsus with relatively broad genital bulb drawn out into broad neck, embolus cat claw-shaped, not twisted, forming beak-like structure with spatula-shaped tegular projection (coupling projection) ( Fig. 3A, B View FIGURE 3 ); sperm ducts with two loops, both lateral and basal to embolus tube ( Fig. 3A, B View FIGURE 3 ).

Female paratype. Body length 4.4; carapace length 2.16, width 1.16; carapace index 53.7; cephalic width 0.81, cephalic index 70; sternum length 0.87, width 0.62, sternum index 71.3; abdomen length 2.12, width 1.59, abdominal index 75; petiole length 0.2; dorsal sclerite length 1.5, width 1.52; epigastric sclerite length 0.55, width 0.9; inframamillary sclerite length 0.2; width 0.4. AER 0.48; AME–AME 0.06; AME–ALE 0.02. PER 0.7; PME– PME 0.2; PME–PLE 0.12.

Posterior part of carapace slightly convex when seen in lateral view ( Fig. 4B View FIGURE 4 ), dorsal sclerite shorter than in male ( Fig. 4B View FIGURE 4 ), 70% of abdomen length, posterior border slightly convex, ventral sclerite absent; remaining somatic characters as in male.

Epigyne. With two widely separated, rounded genital openings mediolateral to spermathecae; two slight pouches (or furrows) posterior to each opening (maybe for fitting of male palpal projection) ( Fig. 3D View FIGURE 3 ); separation between primary and secondary spermathecae slightly visible, primary and secondary spermathecae forming eggplantshaped spermathecae ( Fig. 3E View FIGURE 3 ), copulatory ducts short, at level of copulatory openings, entering the spermathecae posteriorly.

Variation. There was no visible intra-specific variation, except for that inherent in the gender dimorphism.

Geographical and ecological distribution. This species is only known from the localities in Urubo and Santa Maria la Antigua, Santa Cruz department, Bolivia. In both localities, specimens were collected from low herbaceous plants in Cerrado-like vegetation along edges of Chiquitano and Cerradao forest ( Fig. 1 View FIGURE 1 ). In Urubo, M. haddadi sp. nov. was observed co-occurring with the Castianeirinae species Mazax cf. ramirezi Rubio & Danişman, 2014. Despite high sampling effort in several Bolivian forest ecoregions ( Perger & Perger 2017; Perger & Rubio 2018, 2020a, b, 2021), the new species was not observed in forest habitats.

Ant mimicry. In the other Bolivian species of Myrmecotypus , the color of body parts and the color and distribution of setae increases the resemblance to specific ant models of the tribes Camponotini or Dolichoderini ( Perger & Rubio 2020a, 2021). Unfortunately, the life habitus of the new species was not documented and the loss of setae due to the storage in ethanol hampered the assessment of mimetic relationships. However, as in the other congeners, the body size, obovate carapace and short oval abdomen mostly resemble ants of Camponotini or Dolichoderini. Additional field observations are needed to identify potential ant models.