Montinumen, Zhao & Huang & Ma, 2025
|
publication ID |
https://doi.org/10.11646/zootaxa.5717.1.7 |
|
publication LSID |
lsid:zoobank.org:pub:2DA30496-6B59-451C-9845-F5238C35AE21 |
|
persistent identifier |
https://treatment.plazi.org/id/2B53D526-FF81-FFBB-8FB1-F841E764BD6E |
|
treatment provided by |
Plazi |
|
scientific name |
Montinumen |
| status |
gen. nov. |
Genus Montinumen gen. nov.
[Chinese name: ƜṘDzȃ]
Type Species. Montinumen cryptovium gen. nov. et sp. nov., by current designation.
Diagnosis. Medium sized (CW ≤ 35mm). Carapace boarder than long, dorsal surface convex, covered with small granules ( Fig. 1 View FIGURE 1 ); epigastric cristae low, smooth, fused with postorbital cristae, separated by a shallow vertical groove; cornea relatively small; external orbital angle relatively reduced, very low to almost flat. Epistomial median lobe narrowly triangular ( Fig. 2A View FIGURE 2 ). Maxilliped III with relatively broad ischium, exopod reaching beyond anterior edge of ischium, with long flagellum ( Fig. 3A View FIGURE 3 ). Cheliped palm surface rugose ( Fig. 3D, E View FIGURE 3 ). Ambulatory legs long, slender ( Fig. 1 View FIGURE 1 ). Male anterior thoracic sternum (thoracic sternites 1–4) wide, width 1.8 times of length ( Fig. 2B View FIGURE 2 ). Male pleon narrowly triangular ( Fig. 2C View FIGURE 2 ). G1 slender, terminal segment relatively long, inner margin with large, rounded basal-dorsal flap ( Fig. 3C, F, G View FIGURE 3 ). G2 with long flagellum-like terminal segment ( Fig. 3B View FIGURE 3 ). Female vulva sub-ovate, very large, reaches to suture between sternites IV/V ( Fig. 2F View FIGURE 2 ).
Etymology. The genus name is an arbitrary combination of the Latin words montis and numen, meaning “mountain” and “deity”. The name alludes to the historical and cultural importance of local deity temples in mountainous areas, which have become increasingly rare in modern times.
Distribution. Maguan county, Wenshan Zhuang and Miao Autonomous Prefecture, Yunnan Province, China.
Remarks. Montinumen gen. nov. is superficially similar to Tiwaripotamon Bott, 1970 , Teretamon Yeo & Ng, 2007 and Erebusa Yeo & Ng, 1999 in their slender ambulatory legs and carapace dorsal surface structure. Montinumen gen. nov. is also distributed closely to Indochinamon Yeo & Ng, 2007 and Barbamon Shi, Pan & Sun, 2022 geographically. However, the new genus can be distinguished from these by a number of morphological characters. Montinumen gen. nov. can be separated from Tiwaripotamon and Barbamon by its third maxilliped exopod with long flagellum ( Fig. 3A View FIGURE 3 ) (verses short flagellum in Tiwaripotamon (see Dai 1999: pls. 339–342), and in Barbamon ; see Shi et al. 2022: fig. 4A). Montinumen gen. nov. can also immediately be separated from Teretamon by its male sternopleonal cavity reaching anteriorly to imaginary line joining medial part of cheliped coxae ( Fig. 2B, C View FIGURE 2 ) (verses male sternopleonal cavity exceeding imaginary line joining medial part of cheliped coxae, almost reaching suture of anterior thoracic sternites 2/ 3 in Teretamon ; see Yeo & Ng 2007: fig. 13C; Mitra et al. 2018: fig. 2C; Absar et al. 2017: fig. 2C; Pan et al. 2021: fig. 2C). Montinumen gen. nov. can be differed from Indochinamon by its smaller size (CW ≤ 35 mm) (verses medium to large (CW ≤ 65 mm) in Indochinamon ; Zhang et al. 2020) and more slender ambulatory legs ( Fig. 1 View FIGURE 1 ) (verses stout in Indochinamon ; see Dai 1999: pls. 157–186, pl. X figs. 1–8, pl. XI figs.1–8, pl. XII fig. 1). Montinumen gen. nov. can be distinguished from Erebusa by having less reduced eyes and cornea with longer eyestalk ( Figs. 1 View FIGURE 1 , 2A View FIGURE 2 ) (verses strongly reduced eyes, slightly reduced cornea and short eyestalk in Erebusa ; see Yeo & Ng 1999: fig. 1A–E). Meanwhile, Montinumen gen. nov. can also be distingused immediately from the two other stygomorphic freshwater crab genera from China, Phasmon Huang, Ahyong & Shih, 2020 and Diyutamon Huang, Shih & Ng, 2017 by having body pigmentation and functional eyes ( Fig. 5B View FIGURE 5 ) (verses overall depigmented and strongly reduced eye structures in both Phasmon (see Huang et al. 2020c: figs. 1, 2A), and Diyutamon ; see Huang et al. 2017: figs. 2A, B, 3A–D). Furthermore, Montinumen gen. nov. can be distinguished from all these genera by having a large semicircle basal-dorsal flap on the proximal third of G1 terminal segment ( Fig. 3D View FIGURE 3 ) (verses none to small basal-ventral flap on the proximal third of G1 terminal segment in Tiwaripotamon (see Dai 1999: pls. 339–342); no flap on the proximal third of G1 terminal segment in Indochinamon (see Dai 1999: pls. 157–186), Phasmon (see Huang et al. 2020c: figs. 3C, 4A–B), and Diyutamon (see Huang et al. 2017: figs. 5A, C, 6A–B); low basal-dorsal flap extending entire length of G1 terminal segment in Barbamon (see Shi et al. 2022: figs. 4B, C, 5A, B); bent obliquely outward at median part, with a small and narrow hump at the bending point on inner margin of G 1 in Erebusa (see Yeo & Ng, 1999: fig. 3A–G); and dorsal flap extending almost entire length of G1 terminal segment in Teretamon ; see Yeo & Ng, 2007: fig. 13D; Mitra et al. 2018: fig. 4A–D; Absar et al. 2017: fig. 3A–D; Pan et al. 2021: fig. 3C, D). Montinumen gen. nov. can also be separated from these genera by its very large female vulva that reaches to the sternites IV/V suture ( Fig. 2F View FIGURE 2 ) (verses small to medium sized female vulva that does not reach to suture between sternites IV/V in Tiwaripotamon (see Dai 1999: pls. 339–342), Barbamon (see Shi et al. 2022: fig. 3D), Indochinamon (see Dai 1999: pls. 157–186), Erebusa (see Yeo & Ng, 1999: fig. 4B), Phasmon (see Huang et al. 2020c: fig. 2F), Diyutamon (see Huang et al. 2017: fig. 7E), and Teretamon ; see Mitra et al. 2018: fig. 3D; Absar et al. 2017: fig. 4C; Pan et al. 2021: fig. 5C). More detailed comparisons are provided in Table 1.
No known copyright restrictions apply. See Agosti, D., Egloff, W., 2009. Taxonomic information exchange and copyright: the Plazi approach. BMC Research Notes 2009, 2:53 for further explanation.