Plectrogonodesmus, Hoffman, 2012

Hoffman, Richard L., 2012, New Genera For Two Poorly-Known Millipeds From Bahia (Polydesmida: Chelodesmidae), Papéis Avulsos de Zoologia 52 (8), pp. 103-110 : 103-110

Plectrogonodesmus gen. nov.

Type species: Leptodesmus gounellei Brölemann, 1903 .

Name: A neologism composed of the Greek elements plektron (a spur) + gonos (denoting the male reproductive appendage) + - desmus (a combining suffix widely employed throughout the order, from the original Polydesmus ). Masculine.

Diagnosis: Body size large, length to near 70 mm. Among the known genera with enlarged gonopod aperture and prominent sclerotized median gonosternal sclerite, this new genus is characterized by the elongated paramedian processes of the 4 th segment in males, by small paramedian sternal lobes on segments 13-17 in males, by the greatly extended lateral prolongation of the gonopod coxa, and especially by the unusually long and etiolated elements of the telopodite. The efferent groove, visible for its entire length in mesal aspect, terminates on a long, slender subterminal solenomere.

Species: Only the type species is known.

Distribution: The genus is known only from the type locality of the single included species, in the interior of the state of Bahia.

Comment: The large black and yellow milliped named Leptodesmus gounelli by Brölemann in 1903 from a single male collected in the “Sertão” of Bahia, has apparently not been subsequently documented nor represented in museum collections normally holding these arthropods. The species was described in great detail and amply illustrated, with sufficient information to preclude its accommodation in Leptodesmus as currently defined, nonetheless it has remained an enigmatic, unplaced waif in the Brazilian fauna. Study of the holotype has disclosed additional structures not specified by Brölemann that confirm separate generic status for this striking species.

The unusually large gonopod aperture and sclerotized, bilobed, median sternal element suggest the form characteristic of the genera Eucampesmella Schubart, 1955 , Leiodesmus Silvestri, 1987 , and Euthydesmus Silvestri,1902 , and it is perhaps to this last genus that we may look for a near relative despite the disparity in their ranges ( E. acicarina Silvestri occurs in Mato Grosso do Sul). Structure of the undescribed female genitalia in all these chelodesmids may be decisive in developing a classification.