Landouria elegans, Nahok & Tumpeesuwan & Tumpeesuwan, 2021

Nahok, Benchawan, Tumpeesuwan, Sakboworn & Tumpeesuwan, Chanidaporn, 2021, Five new species of the land snail genus Landouria Godwin-Austen, 1918 (Gastropoda, Camaenidae) from northeastern Thailand, with note on genitalia and radula morphology of Landouria diplogramma (Möllendorff, 1902), European Journal of Taxonomy 767 (1), pp. 142-166 : 158-159

publication ID	https://doi.org/ 10.5852/ejt.2021.767.1495
publication LSID	lsid:zoobank.org:pub:9F019E02-95E7-4B6A-B5BC-01F8E26F3466
DOI	https://doi.org/10.5281/zenodo.5528096
persistent identifier	https://treatment.plazi.org/id/6A33A2BA-7197-4C1E-AEB3-D7815F8A05AC
taxon LSID	lsid:zoobank.org:act:6A33A2BA-7197-4C1E-AEB3-D7815F8A05AC
treatment provided by	Felipe
scientific name	Landouria elegans
status	sp. nov.

Treatment

Landouria elegans View in CoL sp. nov.

urn:lsid:zoobank.org:act:6A33A2BA-7197-4C1E-AEB3-D7815F8A05AC

Figs 3E View Fig , 4E View Fig , 5E View Fig , 6M–O View Fig ; Tables 1–4 View Table 1 View Table 2 View Table 3 View Table 4

Landouria sp.3 – Yingkhamhang 2016: 23–24, 39–45, 47–48, 61, 74, figs 4.5, 4.6, 4.21–4.23c, 5.1c, 5.2c.

Diagnosis

Shell similar to Landouria circinata sp. nov., but with a sharper and more prominent keel at the periphery and dark brown zones on the periphery, just above and below the keel. Flagellum droplet shaped, penis long and cylindrical, vagina and free oviduct very short. Radula with elongate tongue-shaped central and lateral teeth.

Etymology

The specific epithet ‘ elegans ’ (Latin for ‘magnificent’) refers to the beauty of the shell.

Type material

Holotype THAILAND • shell (SH 10.0 = mm, SW 17.7 = mm, AH = 6.4 mm, AW = 7.1 mm, UW = 3.6 mm); Khon Kaen Province, Phu Pha Man District, Phu (mountain) Hua Chang ; 16°39′10.54″ N, 101°48′6.67″ E; alt. 305 m; 3 May 2018; B. Nahok, S. Tumpeesuwan and C. Tumpeesuwan leg.; NHMSU-00032 . ( Fig. 3E View Fig ) GoogleMaps

Paratypes THAILAND • 11 shells; 9 living specs; same collection data as for holotype; GenBank No. MN449408 View Materials and MZ435751 View Materials ; NHMSU-00033 GoogleMaps .

Description

SHELL ( Fig. 3E View Fig , Table1 View Table 1 ). Dextral, conical, relatively large-sized.Whorls 6. Protoconch with radially elongated wrinkles. Suture rather shallow, apex obtuse depressed, with rather high conical spire. Last whorl with a sharp keel that is distinctly bent downwards. Colour brownish-corneous with a dark brown zone bordering the keel at the periphery. Umbilicus very deep and wide. Apertural lip thickened, rounded rhombic.

GENITAL SYSTEM (n = 3) ( Fig. 5E View Fig , Table 4 View Table 4 ). Penis longer than vagina, cylindrical, internally with four corrugated, longitudinal pilasters; verge absent. Epiphallus shorter than penis, distal part (ep2) small, whereas proximal part (ep1) is swollen. Flagellum droplet-shaped, without nodes, internally with four corrugated, longitudinal pilasters. Vas deferens long, cylindrical, proximal part that connects to free oviduct somewhat thicker than distal part, entering the flagellum at its base. Vagina very short, internally with five corrugated longitudinal pilasters. Free oviduct shorter than vagina. Proximal part of gametolytic sac rather stout, but tapering to become a slender tube with large oval sac at distal end. Uterus and prostate gland very long and large.

RADULA (n = 3). Comprises 110–114 transverse rows with 69–77 teeth per row; radular formula: (22–24)- (12–14)-1-(12–14)-(22–24). Central and lateral teeth unicuspid, tongue-shaped. Central tooth smaller and shorter than lateral teeth ( Fig. 6M–N View Fig ). Marginal teeth asymmetric, tricuspid with small endocone; mesocone large with curved margins; ectocone triangular and located at tooth base ( Fig. 6N–O View Fig ).

Remarks

Landouria elegans sp. nov. is conchologically quite similar to L. circinata sp. nov. and L. strobiloides , from which it differs by its sharper and more distinct keel with its downward bent rim ( Fig. 3A View Fig vs Fig. 3E View Fig ). The radula of L. elegans sp. nov. resembles that of L. circinata sp. nov., but central tooth and lateral teeth of L. elegans sp. nov. are longer and more slender than in L. circinata sp. nov. ( Fig. 6A–C View Fig vs Fig. 6M–O View Fig ). Epiphallus of L. elegans sp. nov. is similar to that of L. chloritoides sp. nov., but in L. elegans sp. nov. it is larger and connects with the vas deferens near the flagellum base ( Fig. 5D View Fig vs Fig. 5E View Fig ).