Atlantodesmus Hoffman, 2000

Bouzan, Rodrigo Salvador, Pena-Barbosa, João Paulo P. & Brescovit, Antonio Domingos, 2017, Taxonomic review of the genus Atlantodesmus Hoffman, 2000 (Polydesmida: Chelodesmidae), Zootaxa 4236 (2), pp. 269-290 : 271

publication ID	https://doi.org/ 10.11646/zootaxa.4236.2.3
publication LSID	lsid:zoobank.org:pub:8A62CD73-AE84-47D1-8E31-9FD256086BF1
DOI	https://doi.org/10.5281/zenodo.6002126
persistent identifier	https://treatment.plazi.org/id/2B5A8354-FF8B-EB26-FF57-6B8626C8F81D
treatment provided by	Plazi
scientific name	Atlantodesmus Hoffman, 2000
status

Treatment

Genus Atlantodesmus Hoffman, 2000 View in CoL

Atlantodesmus Hoffman, 2000: 101 View in CoL –113. Type species: A. eimeri ( Attems, 1898) View in CoL , by original designation. Iemanja Hoffman, 2000: 101 View in CoL –113. Type species: I. teresa Hoffman, 2000 View in CoL . New synonymy.

Justification of synonymy: Hoffman (2000) described two genera, similar in body features and gonopod structures: Atlantodesmus View in CoL and Iemanja View in CoL . Despite the similarities, Hoffman (2000) distinguished both genera through two features: presence of a cingulum and folds in the posterior margin of the gonopod opening in Iemanja View in CoL (see Hoffman, 2000, figs 2, 14).

Our examination of specimens of the genus Atlantodesmus revealed that all species have folds at the posterior edge of the gonopod aperture, as well as a discontinuity in the transition zone between the prefemoral region and the acropodite region, indicating the presence of a cingulum in ectal view in all species. Hence, there is no reason to separate the species into two distinct genera.

Diagnosis. Males of Atlantodesmus differ from other chelodesmid genera by the combination of the following characters: transition zone of the pre-femoral region to the acropodal region with a cingulum ( Fig. 7 View FIGURE 7 C, 10C); acropodite branching proximally, forming long, thin falciform solenomere and a large acropodite process with a broadened apical region and overreaching the tip of the solenomere.

Description. Body length between 40 mm ( A. itapurensis ) and 74 mm ( A. teresa ). Coloration (specimens preserved in alcohol) variable among species, ranging from black to light brown. Head: face with three rows of bristles ( Fig. 1 View FIGURE 1 A), shape of the Tömösváry organ suboval ( Fig. 1 View FIGURE 1 B). Antenna: distal antennomere with invaginations between the four apical sense cones and spiniform basiconic sensilla ( Figs 1 View FIGURE 1 C–E). Body rings: integument with small tubercles on the metazonite ( A. eimeri ), rough in A. pintoi and A. teresa , and smooth in A. itapurensis and A. pickeli , all of them without bristles. Collum: anterior border arched and posterior border ranging from straight to slightly curved ( Figs 2 View FIGURE 2 A–B). Segments with lateral projections ( Figs 8 View FIGURE 8 B, 11B, 15A, 18B) dorsal to the stigma. Stigma oval ( Fig. 2 View FIGURE 2 E). Sternite of fourth segment with two ventral projections in A. itapurensis and A. teresa ( Figs 11 View FIGURE 11 A; 18A). Ozopore situated on the posterior edge of paranota. Ozopore arrangement: 5, 7, 9, 10, 12, 13, 15–19; ozopores surrounded by peritremata ( Figs 2 View FIGURE 2 C–D). Paranota: prominent and long, wide and nearly horizontal, slightly elevated on sides, covering part of the legs, without bristles on the edges. Paranota form: anterior corners rounded, posterior edges acutely produced ( Fig. 2 View FIGURE 2 C). Legs: without modifications, with thin and slightly elongated bristles ( Fig. 1 View FIGURE 1 F). Telson: triangular ( Fig. 2 View FIGURE 2 F), with five pairs of macrobristles on the dorsal side and two pairs in the apical region.

Male characters: Gonopore: located on the coxae of the legs of the third segment, coxae rectangular, with an apical pore ( Fig. 3 View FIGURE 3 C). Gonopod aperture on seventh body ring: transversely oval, large; posterior edge with folds ( Figs 7 View FIGURE 7 E–F). Central support of gonopods are sclerotized ( Fig. 7 View FIGURE 7 E, arrow). Gonopods: Gonopod coxae width ( Fig. 3 View FIGURE 3 A): equivalent to about half the length of the telopodite, often with spiniform process ( Fig. 3 View FIGURE 3 B); coxae prominent in ectal view. Cannula ( Fig. 3 View FIGURE 3 A): hook-shaped. Spermatic (prostatic) groove ( Fig. 3 View FIGURE 3 A): runs along mesal side of the acropodite, does not change trajectory at the cingulum. Telopodite ( Fig. 3 View FIGURE 3 A): elongated and inclined, divided into two parts: the prefemoral region ( Fig. 3 View FIGURE 3 A) and the femoral region ( Fig. 3 View FIGURE 3 A). Prefemoral process ( Fig. 3 View FIGURE 3 A): long branch without projections, reaching almost tip of solenomere. Cingulum: delimiting the prefemoral region and femoral region ( Fig 3 View FIGURE 3 B); conspicuous in A. itapurensis and A. teresa , and reduced in A. eimeri , A. pickeli and A. pintoi . Cingulum difficult to observe even using a stereomicroscope in A. eimeri and A. pintoi . Solenomere ( Fig. 3 View FIGURE 3 A): elongated and sickle-shaped, rising proximally from the femoral region; shielded by large and broad acropodite process ( Fig. 3 View FIGURE 3 A); acropodite process shape species-specific. Female characters: Cyphopods: ovalshaped, situated directly behind the second pair of legs on the third segment; composed of three valves, all of them with bristles; two valves joined by a membrane, with a third apically, appressed against both larger valves ( Fig. 3 View FIGURE 3 D).

Distribution. Known from the states of Bahia to Santa Catarina, occurring in the Atlantic rain forest and in the Cerrado area of Brazil ( Fig. 19 View FIGURE 19 ).

Composition. Five species, Atlantodesmus eimeri ( Attems, 1898) , A. itapurensis ( Schubart, 1943) , A. pickeli ( Schubart, 1946) , A. pintoi ( Schubart, 1946) , A. teresa ( Hoffman, 2000) , new combination.