Mictlana Cruz-López & Francke, 2015

Cruz-López, Jesús A., 2021, Two new genera and two new species of troglobitic harvestmen of Stygnopsidae (Opiliones, Laniatores, Gonyleptoidea) from Oaxaca, Mexico, with notes on selected morphological characters, Zoosystema 43 (5), pp. 101-112 : 102-104

Genus Mictlana Cruz-López & Francke, 2015

Mictlana Cruz-López & Francke, 2015: 878 . — Cruz-López 2018a: 534; 2018b: 80. — Aguiñaga & Cruz-López 2019: 9. — Cruz-López et al. 2019: 286.

TYPE SPECIES. — Hoplobunus inops Goodnight & Goodnight, 1971 .

EMENDED DIAGNOSIS. — Troglobitic karosins, eyeless, with two dorsal lobes on the prosoma, the small one located in the middle and the anterior one larger and rounded. Scutum rectangular, type iota (i) with the lateral clear areas well marked. Chelicera with heterogeneous dentition, movable finger with a basal triangular tooth. Penis with the pars distalis spear-shaped, with two short pairs of MS C and two pairs of MS A, both contiguous and forming a lateral row.

REMARKS

Cruz-López & Francke (2015) recovered Karos Goodnight & Goodnight, 1944 genera-group clade (currently Karosinae ) with nine synapomorphies: mesotergal areas not completely covered with tubercles, ocularium in the middle of prosoma, ocularium small, cheliceral dentition homogeneous, no sexual dimorphism on chelicera size, males with chelicera small, follis of penis not on apical depression, pedipalpal femur with a mesodistal setiferous tubercle and pedipalpal patella with mesal armature. At that moment, Cruz-López & Francke (2015) considered that the anterior rounded lobe on prosoma of Mictlana inops was the ocularium due to the size of the structure, being in this way a reversion from the synapomorphy “ocularium in the middle” to the anterior position on prosoma in this species. Later, Cruz-López & Francke (2017) postulated the possibility that the small lobe on the middle of the prosoma could be the ocularium by comparison of this structure with the true ocularium of other karosins, and then, the anterior lobe would be a developed frontal bulge, structure widely found in other karosins but poorly studied; without evidence of eyes position, this supposition is uncertain. Clear figures of the frontal bulge are available in the description of Karos morronei Cruz-López, 2018 (Cruz-López 2018a: figs 5-7). Similar problem determining the position of the true ocularium was detected by Cruz-López et al. (2016) on the troglobitic Belizean Jarmilana pecki (Goodnight & Goodnight, 1977) , a pyramidopid harvestman without eyes or retina evidence, and with two dorsal lobes on prosoma.

The character “Chelicera with homogenous dentition”, another synapomorphy of Karosinae , was recovered as a reversion to the plesiomorphic state, heterogeneous dentition, in M. inops in Cruz-López & Francke (2015). In a broader phylogeny of Stygnopsidae , cheliceral dentition is a homoplastic character through the family, causing conflict to a subfamilial allocation of Mictlana and Mexotroglinus based only on this character. According to Cruz-López & Francke (2017), the character describing the shape of the mesotergal sulci has two states evenly distributed between Stygnopsinae and Karosinae . For that, in the present work, the character “mesotergal sulci sinuous” is considered a putative synapomorphy of Karosinae , character clearly illustrated by SEM photographs in Cruz-López & Francke (2017, 2019a) and observed on the holotype of H. planus . Additionally, Cruz-López & Francke (2019a) detected the presence of cheliceral comb in several Karosinae representatives, structure observed on the holotype of M. plana n. comb., but unfortunately that could not be checked in any specimen of M. inops .

Additionally, in the phylogeny of Stygnopsidae proposed by Cruz-López & Francke (2017), Mictlana was recovered as monophyletic with high support (posterior probability 0.91), including a putative female and uncertain immatures of H. planus . Now with the inclusion of H. planus in Mictlana , the presence of a large rounded anterior lobe on prosoma could be considered a putative synapomorphy of this genus, regardless whether or not it is the ocularium or the anterior bulge.