Orphnaecus Simon, 1892

Genus Orphnaecus Simon, 1892 View in CoL

Type species.

Orphnaecus pellitus Simon, 1892 , by monotypy.

Included species.

O. adamsoni Salamanes et al., 2022 , O. kwebaburdeos ( Barrion-Dupo et al., 2015) , O. pellitus Simon, 1892 .

Diagnosis.

Orphnaecus differs from all selenocosmiine genera (including Chilocosmia stat. rev.), except Phlogiellus and Selenobrachys stat. rev., by having a long prolateral superior keel (PS) (= retrolateral keel (R) in West et al. 2012) from tip to base with pronounced basal lobe (BL) on the embolus of males. Orphnaecus differs from Phlogiellus and Selenobrachys stat. rev., (i) in having a reniform patch, proximally broader, of short bacilliform rods, whereby the bacillae in the lowest row are larger, club-shaped, and rounded at the tip, prolaterally (Fig. 20 A, D, G View Figure 20 ). It can also be distinguished from Selenobrachys stat. rev. in having long and dense dorsal palpal brush of setae on patella in males (Fig. 15 A View Figure 15 ), in having a palpal tibia in males proximally swollen and distally tapering (Fig. 15 A View Figure 15 ), and in having long acicular femoral setation on prolateral femur I (Fig. 21 A – D View Figure 21 ).

Remarks.

Raven (1985) and Sivayyapram et al. (2020) distinguished Orphnaecus from other selenocosmiine genera in lacking an unpaired third claw at least on leg IV. However, the absence of a third claw cannot stand alone as the only diagnostic and defining characteristic of Orphnaecus against its known species that possess a third claw, while their genital and lyrate morphology is the same. In the Orphnaecus specimens (including syntypes of O. pellitus ) mentioned and examined herein, we were able to find adult specimens within one species and one locality with a developed third claw, as well as those with a very reduced 3 rd claw, and even a few specimens that did not have a third claw at all (Fig. 5 G View Figure 5 ). Raven (1985) may have examined a type specimen from the same type series of O. pellitus with no third claw. Most of the syntypes and newly collected specimens of O. pellitus possess an unpaired third claw on leg IV (Fig. 15 E View Figure 15 ). Congeners, herein directly examined (types and non-types), also possess a third claw on leg IV. Simon (1892) distinguished Orphnaecus in having tiny and more separated eyes caused by troglomorphic adaptation. However, this is only phenotypic plasticity and cannot serve as a defining characteristic of the genus, as it arises solely from prolonged habitation in completely dark cave environments.

Distribution.

Philippine endemic: Luzon Is. ( Simon 1892), Polillo Is. ( Barrion-Dupo et al. 2015), Catanduanes Is., Masbate Is. ( West et al. 2012), Negros Is. ( Lüddecke et al. 2018), Dinagat Is. ( Salamanes et al. 2022), and Mindanao Is. (Fig. 22 View Figure 22 ). Probably widespread from Luzon PAIC, West Visayas PAIC, to Mindanao PAIC.

Etymology.

Orphnaeus, one of the four horses that drew the golden chariot of Hades, the king of the underworld in Greek mythology, attached with the suffix - cus (probably to avoid homonymy with a centipede genus, Orphnaeus Meinert, 1870). The type species O. pellitus is possibly a troglobitic species, exhibiting troglomorphism and spending its whole life inside the cave ( Simon 1892). Gender is masculine.