Anceyoconcha siamensis ( Redfield, 1853 ) Nahok & Tumpeesuwan & Tumpeesuwan, 2020

Nahok, Benchawan, Tumpeesuwan, Sakboworn & Tumpeesuwan, Chanidaporn, 2020, Anceyoconcha, a replacement name for the preoccupied tree snail genus Giardia Ancey, 1907 (Pulmonata: Helicoidea: Camaenidae), Raffles Bulletin of Zoology 68, pp. 80-90 : 82

publication ID	https://doi.org/ 10.26107/RBZ-2020-0009
publication LSID	lsid:zoobank.org:pub:59055EBA-BFE3-47E4-B445-A0BD6C0366F6
persistent identifier	https://treatment.plazi.org/id/250D87D2-1825-FFB8-0F83-FF4058D3FA96
treatment provided by	Carolina
scientific name	Anceyoconcha siamensis ( Redfield, 1853 )
status	comb. nov.

Treatment

Anceyoconcha siamensis ( Redfield, 1853) View in CoL , new combination

( Figs. 2A View Fig , 3A, B View Fig , 4A View Fig , 5 View Fig , 7A View Fig ; Table 1)

Bulimus siamensis Redfield, 1853: 15 View in CoL ; von Martens, 1860: 9;

Pfeiffer, 1860: 170, pl. 46 figs. 3, 4; Crosse & Fischer, 1863: 360. Bulimus (Napaeus) siamensis – von Martens, 1867: 81, pl. 19 fig. 7. Petraeus siamensis – Morlet, 1889: 128. Petraeus siamensis var. minor Morlet, 1889: 128 View in CoL . Satsuma siamensis – von Möllendorff, 1901: 47. Buliminus siamensis – Fischer & Dautzenberg, 1904: 18. Buliminus (?) siamensis – Dautzenberg & Fischer, 1908: 185. Giardia siamensis – Schileyko, 2003: 1519–1520, fig. 1960;

2011: 46.

Material examined. 1 empty shell, 1 live specimen (NHMSU-00021), 1 empty shell ( ZRCBUU 0325 ), limestone hills, Khao Chakan District (13°39′41.73″N, 102°5′32.33″E), Thailand, at an elevation of about 130 m above mean sea level GoogleMaps .

Diagnosis. Body pale orange to brown ( Fig. 2A View Fig ). Shell pale and shiny ( Fig. 4A View Fig ). Radula with unicuspid lanceolate-shaped central teeth ( Fig. 5 View Fig ). Penis cylindrical in shape, constricted at the distal part connected to atrium. Flagellum is shorter than A. rhombostoma ( Table 1; Fig. 7 View Fig ).

Description. Shell ( Fig. 4A View Fig ). Sinistral, elongate-conic, SH 15.0 mm (SH 13–23 mm according to Schileyko, 2003), SW 7.0 mm (13–23 mm according to Schileyko, 2003), AH 2.5 mm and AW 5.0 mm. Whorls 7. Pale grey to light brown colour, rather transparent and lustrous. Apex obtuse. Aperture large, rounded. Peristome with reflexed and expanded outer lip. Umbilicus narrow, deep, half-closed by peristome.

Body ( Fig. 2A View Fig ). Living snails with pale orange to brown body. Foot rather narrow and short with pale margin.

Radula ( Fig. 5 View Fig ). Comprises 88–90 transverse rows of teeth, and 45–53 teeth in each row ( Fig. 5A, B View Fig ). Dentition formula: (16–18) + (6–8) + C + (6–8) + (16–18). Central teeth symmetric unicuspid lanceolate-shaped ( Fig. 5B, C View Fig ). Lateral teeth similar to central tooth, but differ in being more oblique and with wider and longer cusps ( Fig. 5C View Fig ). Teeth on both sides begin transition into indistinct bicuspid marginal teeth with tiny ectocone at numbers 9–11 ( Fig. 5D, E View Fig ). Marginal teeth gradually change to broad tricuspid at numbers 12–14 ( Fig. 5D, E View Fig ), and begin transition into tetracuspid with two small finger-shaped ectocones from numbers 19–21 to end of teeth ( Fig. 5B, E View Fig ).

Genital system ( Fig. 7A View Fig ). Atrium (at) short. Penis (p) cylindrical and constricted at the part connected to atrium. Penial retractor muscle (prm) long. Epiphallus (ep) short and approximately half of penis length. Flagellum (fl) length approximately equal to epiphallus length; cylindrical; with relatively tiny distal hook. Vas deferens (vd) long. Vagina (v) longer than penis. Gametolytic duct (gd) extending from vagina, long slender to small tube distally. Gametolytic sac (gs), spear shape connected to distal end of gametolytic duct. Free oviduct (fo) short. Uterus (ut) and prostate gland (pro) long.

Habitat. This is an arboreal species that lives about 1–2 m above ground surface ( Fig. 3A, B View Fig ). Thus far seen only in natural forests and can be found from the foothills to higher elevations.