Myrmecium gounellei Simon, 1896

Marusik, Yuri M., Omelko, Mikhail M. & Koponen, Seppo, 2015, A redescription of the ant mimicking spider Myrmecium gounellei (Araneae: Corinnidae, Castianeirinae), with notes on the genus, Zootaxa 3985 (2), pp. 296-300 : 298-300

Myrmecium gounellei Simon, 1896

Figs 1–7 , 15–22

Myrmecium gounellei Simon, 1896: 410 (♂♀).

Myrmecium gounellei: Simon, 1897: 164 , fig. 172 (♀, habitus only); Petrunkevitch 1911: 494; Mello-Leitão, 1932: 158, fig. 13 (♀ habitus, copy of figure from Simon [1897]).

Material examined. Syntypes (?) 1♂ 1 ♀ "M [useum] Paris".

Note. Simon (1896) provided no exact information about number of specimens he used while describing the new species. It is possible that two specimens examined are the only existing syntypes, or a part of syntypes. Type locality as quoted in the description is " Brasilia: Rio Salobro, Terra Kova (prov. Bahia) (E. Gounelle)".

Diagnosis. Myrmecium gounellei can be compared only to those few species of this genus that are relatively well illustrated. Myrmecium gounellei differs from the type species M. rufum and from M. itatiaiae by having a shorter abdomen (cf. Figs 1, 6 , 9–10, 15 ), longer retrolateral tibial apophysis, and shorter swollen part of spermophor (cf. Figs 12, 13 , 19 ). It differs from M. obscurum Keyserling, 1891 ( Fig. 8 ) by a longer and narrower carapace and a pointed abdomen (round in M. obscurum ). The general appearance of M. gounellei is rather similar to that of M. bifasciatum Taczanowski, 1874 (cf. Figs 6 , 14–15 ), whose copulatory organs are not known. It is possible that M. gounellei could be a junior synonym of the latter species.

Description. Male. Total length 6.55. Carapace 4.48 long, 1.45 wide. Carapace fused with sternum, with two conspicuous constrictions (plus one less marked behind the coxa IV), cephalic part almost two times wider than the posterior part of thoracic region; carapace brown with lighter median part, covered with numerous small tubercles and sparse long hairs. Chelicerae, maxillae and anterior part of carapace yellowish. Chelicera without teeth but with strong brush of setae on anterior margin. Petiolus long, about 2.5 longer than wide. Abdomen yellow with two distinct transversal brownish lines, venter lighter than dorsum; dorsum with poorly distinct scutum (Ds) occupying about half of abdomen; epigastral scutum (Es) almost indistinct, other scuta lacking. Legs yellowish, femora with dark prolateral and retrolateral stripes; coxae subequal in size; coxae I–II spaced by more than 2 diameters, while coxae III–IV spaced by half of their diameter. Spination: leg I without spines; leg II: metatarsus 1v; leg III: tibia 2- 1v; metatarsus 1- 1v; leg IV: tibia 1v; metatarsus 1p, 1- 1v.

Palp as in Figs 16–19 . Tibia subconical (wider in apical part than in basal) with two apophyses: retrolateral (Rl) and retroventral (Rv); retrolateral apophysis small (smaller than diameter of tibia) and bent in middle part; retroventral apophysis well distinct in ventral view only, its tip bears a sort of brush (Br) of strong setae. Cymbium long, with small outgrowth (So) in retrobasal part, almost three times longer than wide (in the widest part), tip of cymbium as long as basal part. Bulbus slightly shorter than cymbium; tegulum almost round, two times shorter than embolic part; spermophor meandering, forming transversal loop (Tl); spermophor in the embolus rather thick tapering, terminal part swollen and stronger sclerotised (Sp); embolus proper (Ep) short, screw-like.

Leg joint measurements (♂ / ♀) Female. Total length 7.75. Carapace 4.48 long, 1.6 wide. General appearance as in male. Coloration as in male but somewhat darker. Abdomen with distinct dorsal scutum (Ds) occupying anterior 1/3 of abdomen, and distinct epigastral scutum (Es) encircling petiolar extension (tube); inframammillary scutum absent or indistinct. Spination: palp with 3 strong prolateral spines; leg I: tibia 3- 2v; metatarsus 2- 2v; II: tibia 3- 2v; metatarsus 2- 2v; III: tibia 2- 2v; metatarsus 1r, 2- 2v; IV: tibia 1v; metatarsus 1p, 1- 1v.

Epigyne as in Figs 20–22 . Intact epigyne with mating plugs (Mp) ( Figs 4 , 20 ) formed by kind of secretion; copulatory opening (Co) large and round, bursa copulatrix (Bc) large, rounded, larger than receptacle (Re); receptacles round, with coiled ducts inside forming several round chambers (Rc), connected with bursa copulatrix by short insemination duct (Id).

Distribution. The species is known only from the type locality.

Figures

FIGURES 1 – 7. Somatic characters of Myrmecium gounellei, female (1 – 5) and male (6 – 7). 1, 6 habitus, dorsal; 2 prosoma and petiolus, ventral; 3 prosoma, lateral; 4 abdomen, lateral; 5, 7 abdomen, dorsal. Abbreviation: Ds dorsal scutum, Es epigastric scutum, Mp mating plug.

FIGURES 8 – 15. Original illustrations of several Myrmecium species showing habitus and copulatory organs. 8 M. obscurum (habitus, epigyne and palp); 9, 11 male of M. itatiaiae (habitus and palp); 10 M. rufum (habitus, epigyne and palp); 12 M. rufum (bulb and cymbium); 13 M. rufum (male palpal tibia, retrolateral); 14 – 15 habitus of M. bifasciatus and M. gounellei respectively. Figs 8, 10 after Keyserling (1891); 9, 11 after Mello-Leitão (1932); 12 – 13 after Camargo (1953); 14 after Taczanowski (1874); 15 after Simon (1896).

FIGURES 16 – 22. Copulatory organs of Myrmecium gounellei. 16 – 19 male palp, ventral, prolateral, dorsal and retrolateral; 20 intact epigyne with mating plugs; 21 epigyne and epigastral scutum after maceration, ventral; 22 epigyne, dorsal. Scale = 0.2 mm. Abbreviations: Bc bursa copulatrix, Br brush of strong setae, Eo Co epigynal opening, Ep embolus proper, Id insemination duct, Mp mating plug, Rc round chambers, Re receptacle, Rl retrolateral tibial apophysis, Rv retroventral apophysis, So small outgrowth, Sp spermophor, Tl transversal loop of spermophor.