Everettia jucundior, Liew & Schilthuizen & Vermeulen, 2009

Liew, Thor-Seng, Schilthuizen, Menno & Vermeulen, Jaap Jan, 2009, Systematic revision of the genus Everettia Godwin-Austen, 1891 (Mollusca: Gastropoda: Dyakiidae) in Sabah, northern Borneo, Zoological Journal of the Linnean Society 157 (3), pp. 515-550 : 538

publication ID	https://doi.org/ 10.1111/j.1096-3642.2009.00526.x
DOI	https://doi.org/10.5281/zenodo.5492195
persistent identifier	https://treatment.plazi.org/id/03F9878A-FF98-E814-0D36-8D7D261DFBBC
treatment provided by	Felipe
scientific name	Everettia jucundior
status	sp. nov.

Treatment

EVERETTIA JUCUNDIOR View in CoL SP. NOV.

Everettia subconsul, Laidlaw, 1931: 196–200 View in CoL , figures 3, 4, 6.

Type material: MALAYSIA: State of Sabah: Tawau District . Tawau Hills Park (4°24 ′ N, 117°53 ′ E). Collected by Jacqueline Peter King. Date: xii.2001, holotype, BOR/MOL 1375, Figure 2F View Figure 2 GoogleMaps ; MALAYSIA: State of Sabah: Kinabatangan District . Bod Tai limestone (5°31 ′ N, 118°13 ′ E). Collected by Menno Schilthuizen. Date: 16.v.2002, one paratype in BMNH 20080629 GoogleMaps .

Etymology: This species is named jucundior because of its shell surface sculpture: similar to (but even more jocund than) that of Everettia jucunda .

Material examined: SABAH – Tawau: BOR/MOL 922, Batu Baturong 100 m alt., vii.2000 ; BOR/MOL 1376, Tawau Hills Park, ii.2002. Lahad Datu: JJ 1215 , Segama Valley, Kirk’s Cave , ix.1986 . Tabin Wildlife Reserve : BOR/MOL 5268, i.2005 . Danum Valley : BOR/MOL 1231, v.2000 . Kinabatangan : BOR/MOL 1387, Batu Tomanggong Besar, iv.2002 ; BOR/MOL 5269, Batu Mawas, iii.2003; BOR/MOL 5270, Bod Tai, v.2002; BMNH 1897.5.13.2-5, Abai river, 1897; BMNH 1897.5 .13.1, Abai river , 1897. Crocker Range: ZMA 176863 View Materials , Keningau, Kampung Matou, i.1965 . Semporna: JJ 1823 , Segarong Hills , Batu Tengar, i.1987 .

Diagnostic characteristics: Shiny shell with dense spiral striation above shell. The species differs from E. jucunda (which has similar sculpture) in terms of the shell shape and size ( E. jucundior with five whorls and shell 19 mm in width vs. E. jucunda – with six and a half whorls and shell 17 mm in width).

Description: Shell ( Figs 2F View Figure 2 , 11F View Figure 11 ): medium-sized, rather thin, brownish, moderately elevated, outer whorls slightly shouldered or rounded. Periphery rounded. Above the periphery, shell shiny with densely placed spiral striation, c. 20–30 striae per mm. Below the periphery, shell has fine, densely placed spiral grooves. Height up to 10.9 mm; width up to 19.5 mm; diameter of the first three whorls 0.9, 0.8, and 1.3 mm, respectively; number of whorls up to five and one-fifth; height aperture up to 8.3 mm; width aperture up to 10.1 mm. Genitalia ( Fig. 7G View Figure 7 ): maximum length from genital opening to the end of dart-sac (before the visible gland tubules) up to 11 mm. The penis, dart-sac, and vagina with thick muscular walls. P, V, GO, BC, and DS arranged around the short genital atrium, with limited space between the opening of each of the genital structures. BC short, about one-third of total DS length. Animal ( Fig. 8H View Figure 8 ): black bands on either side of the tentacles, which are separated by a white band that occupies the space between the eye tentacles and extends downward to just below the eye tentacles. Grey smear on either side of the tail extending from the umbilicus region to the end of the tail. Other parts of the animal are clear from any markings. The mantle is black and covered by crowded tiny bright spots and followed by regularly spaced radial black bands in the last half whorl.

Distribution and habitat: Primary forest. Sabah: Kinabatangan, Tawau Hills Park, Danum valley ( Fig. 5C View Figure 5 ).

Remarks: The specimens in Laidlaw (1931) were collected by R. Hanitsch in 1899 in British North Borneo. According to the description by Laidlaw, these shells’ size and sculpture fit with the material we consider as E. jucundior . Some material in the RMNH and JJ collections from Balikpapan (Southeast Coast of Kalimantan) and Sarawak’ Fourth Division have similar spiral striation and shell shape but we do not include them in this Sabah Everettia revision. Our genetic data also show that E. jucundior is not closely related to other Sabah lowland Everettia species.