Borneosa, Ng & Grinang, 2022

Ng, Peter K L & Grinang, Jongkar, 2022, Establishment of A New Bornean Genus of Gecarcinucidae (Crustacea: Brachyura), with Descriptions of Five New Species., Zoological Studies 61 (13), pp. 1-35 : 32-33

publication ID	https://doi.org/ 10.6620/ZS.2022.61-13
DOI	https://doi.org/10.5281/zenodo.8055980
persistent identifier	https://treatment.plazi.org/id/CF2E433D-3C2D-FF83-FC8D-FD633712FA3A
treatment provided by	Valdenar
scientific name	Borneosa
status

Treatment

Key to species of Borneosa View in CoL

1a. Anterolateral margin with the epibranchial tooth distinct, sharp, separated from rest of anterolateral margin by clear cleft (e.g., Figs. 10B View Fig , 11F, H View Fig ); male sternoplenonal cavity separated from suture between thoracic sternites 2 and 3 by narrow gap, less than combined length of thoracic sternites 1 and 2 (e.g., Fig. 18B View Fig ) .. 2

1b. Anterolateral margin with the epibranchial tooth low to almost absent, cleft when visible, low, shallow, anterolateral margin may appear entire (e.g., Fig. 2B View Fig ); male sternoplenonal cavity separated from suture between thoracic sternites 2 and 3 by relatively wide gap, more than combined length of thoracic sternites 1 and 2 (e.g., Fig. 3B View Fig ) ....................................................................................... 4

2a. Outer margin of exorbital tooth distinctly serrated ( Fig. 17B View Fig ); Bulungan, Kalimantan Utara ........................... B. serrata View in CoL sp. nov.

2b. Outer margin of exorbital tooth entire or almost so (e.g., Fig. 8B View Fig ); Sarawak...................................................................................... 3

3a. Epibranchial tooth low, separated from anterolateral margin by small cleft ( Fig. 8B View Fig ); third maxilliped ischium subquadrate ( Fig. 9A View Fig ); G1 terminal segment relatively slender, long ( Fig. 21A–C View Fig ); Niah, Sarawak..................................................... B. niah View in CoL sp. nov.

3b. Epibranchial tooth strong, separated from anterolateral margin by prominent U-shaped cleft ( Figs. 10B View Fig , 11F, H View Fig ); third maxilliped ischium subrectangular ( Fig. 11A View Fig ); G1 terminal segment relatively stout, short ( Fig. 21E–G View Fig ); Bario Highlands View in CoL , Sarawak.. ............................................................................. B. bario View in CoL sp. nov.

4a. P3 dactylus distinctly more slender and elongate compared to P4 dactylus (e.g., Fig. 5H, I View Fig ) ............................................................ 5

4b. P3 and P4 dactyli not elongate, subequal in length (e.g., Fig. 7F, G View Fig ) ................................................................................................ 6

5a. Frontal median triangle with dorsal margin separated from lateral margins by small gap ( Fig. 2C–F View Fig ); G1 terminal segment relatively short, subcylindrical ( Fig. 20F, G, J, K View Fig ); Gunong Mulu National Park, Sarawak................. B. tenebrosa ( Holthuis, 1979) View in CoL

5b. Frontal median triangle with dorsal margin contiguous with lateral margins ( Fig. 4C–E View Fig ); G1 terminal segment very long, cylindrical ( Fig. 20M–O View Fig ); Brunei and northern Sabah ................. .................................................. B. aspera ( Ng & Stuebing, 1989) View in CoL

6a. Striae on lateral parts of dorsal surface of carapace relatively lower, rounded ( Figs. 6B View Fig , 7I View Fig ); median lobe of posterior margin of epistome acutely triangular ( Fig. 6C–E View Fig ) ....................................... ............. Barito, Kalimantan Tengah B. brachyphallus ( Ng, 2015) View in CoL

6b. Striae on lateral parts of dorsal surface of carapace strong, sharp ( Fig. 15B View Fig ); median lobe of posterior margin of epistome obtusely triangular (e.g., Fig. 15C–E View Fig ) ...................................................... 7

7a. Epibranchial tooth small but usually visible, and even when low, demarcated from the anterolateral margin by a shallow cleft ( Figs. 12B View Fig , 14 View Fig ); G1 terminal segment with median part less distinctly bent, distal part more elongate with more tapering tip, opening small ( Fig. 22A–C, E–G View Fig ); Kapit area and upper Rejang, Sarawak............................................................................. B. kapit View in CoL sp. nov.

7b. Epibranchial tooth not visible or very low, with the anterolateral margin appearing entire ( Fig. 15B View Fig ); G1 terminal segment with median part distinctly bent, distal part ending in rounded tip with wide opening ( Fig. 22I–K View Fig ); Batang Ai National Park and Lanjak-Entimau Wildlife Sanctuary, Kanowit Basin, Sarawak................. ................................................................ B. sarawakensis View in CoL sp. nov.