Aegista diversifamilia, Huang, Chih-Wei, Lee, Yen-Chen, Lin, Si-Min & Wu, Wen-Lung, 2014

Huang, Chih-Wei, Lee, Yen-Chen, Lin, Si-Min & Wu, Wen-Lung, 2014, Taxonomic revision of Aegistasubchinensis (Moellendorff, 1884) (Stylommatophora, Bradybaenidae) and a description of a new species of Aegista from eastern Taiwan based on multilocus phylogeny and comparative morphology, ZooKeys 445, pp. 31-55 : 38-41

Taxon classification Animalia Stylommatophora Bradybaenidae

Aegista diversifamilia sp. n. Figures 7, 8, Table 4, Suppl. material 1, Table S1

Aegista subchinensis Hsieh, 2003: 200, figs; Lee and Chen 2003: 234, figs above text, figs 1-2; Lee and Wu 2004: 13-14, figures 2A, 3D; Hsieh et al. 2006: 250, figs; Wu and Jian 2006: fig 33; Hsieh et al. 2013: 335, figs.

Aegista (Aegista) subchinensis Hemmen and Niederhöfer, 2007: figs 67, figs 80; Wen and Hwang 2014: fig 1.

Type material.

Holotype NMNS-7276-001 (adult dry shell, Figure 7A). Paratypes NMNH-7276-002 (1 juvenile in EtOH) and NHMUK 20140070 (4 adult dry shells, Figure 7 B–E) from the same locality of holotype. NMNH-7276-003 (1 adult dry shell) and NMNH-7276-004 (1 adult dry shell) from the northern entrance of Chongde Tunnel, Xiulin Township, Hualian County, 24°11'31.08"N, 121°39'41.01"E, elevation 62 m. NMNS-7276-005 (6 adult dry shells) and NHMUK 20140071 (2 adult dry shells) from Jinwen Tunnel, Xiulin Township, 24°12'28.7"N, 121°40'23.5"E, elevation 128m.

Type locality.

Taiwan, Hualian County, Xiulin Township, Forest around the Chongde Tunnel, 24°11'22.0"N, 121°39'36.8"E, elevation 56 m.

Other material examined.

Anpingkeng, Dongshan Township, I-Lan County, 24°36'52.5"N, 121°46'38.1"E (3 adult dry shells); Wushibi, Su’ao Township, 24°29'13.5"N, 121°50'02.9"E (1 juvenile in EtOH); Chaoyang Trail, Nan’ao Township, 24°27'35.9"N, 121°48'53.9"E (2 adult dry shells); Heren 1, Xiulin Township, Hualien County, 24°14'49.1"N, 121°43'06.4"E (1 adult dry shells); Heren 2, 24°14'54.8"N, 121°42'51.4"E (7 adult dry shells); Heren Trail, 24°13'58.5"N, 121°42'27.73"E (1 adult and 4 juvenile in EtOH); Southern Chongde Tunnel, 24°11'22.0"N, 121°39'36.8"E (2 juvenile in EtOH); Sanjianwu, 24°10'55.3"N, 121°37'34.3"E (6 adult dry shells); Taroko Service Center, 24°09'31.9"N, 121°37'20.7"E (6 adult dry shells); Badagang, 24°10'36.8"N, 121°33'43.6"E (1 adult and 4 juvenile in EtOH, 6 adult dry shells) (materials mentioned above were deposited in NMNS, NMNH-7276); Hoping Forest Road, (1 adult in EtOH, NMNS-004875-00015 and 1 adult dry shell, NMNS-004962-00038); Sanzhan Northern Stream, (1 adult dry shell, NMNS-003348-00023).

Description.

Shell Morphology. Shell depressed globosed, dextral, medium sized, shell width range 1.98-3.24 cm, shell height range 0.97-1.68 cm, shell height/shell width ratio range 0.43-0.55. Shell thin but solid, glossy with chestnut brown or yellowish-brown, usually with narrow and light brown spiral band on periphery. Shell surface with distinct oblique and curved growth lines. Apex obtuse, angle range 148.56°-165.02°. Spire depressed conic, slightly convex, suture depressed. Whorl range 6.6-8.2 in number, earlier whorl narrow then slowly increases regularly, and last whorl shouldered. Body whorl height range 0.53-0.88 cm. Aperture little descending, ovate or nearly circular, width range 0.78-1.32 cm, height range 0.48-1.05 cm. Peristome white, expanded and reflected. Umbilicus widely open, width range 0.77-1.59 cm. Mean and standard errors of each characteristics were provided in Table 4. Morphological measurements of all specimens were presented in Suppl. material 1, Table S1.

Genital morphology. Atrium thick and short. Penis slender and long. Epiphallus slender, longer than penis. Penis retractor muscle thin and long, attached to one-third part of epiphallus. Epiphallial flagellum thick and long, logner than epiphallus, wider than penis and epiphallus. Dart-sac of auxiliary copulatory organ thick and large, inserted into the base of vagina, with one small accessory-sac of auxiliary copulatory organ. Three mucus glands of the auxiliary copulatory organ. Vagina slender at the base of dart-sac, gradual wider and thick toward free oviduct, inflated at the connected region of free oviduct, about equal length of penis. Free oviduct thick, short,inflated. Pedunculus of bursa copulatory thin and long. Sac of bursa copulatory large and oval. Vas deferens thin and long, wider than penis retractor muscle. Spermoviduct long, about four times longer than penis and oviduct. Hermaphroditic duct slender and long, about half length of spermoviduct. Albumen gland thick and long, longer than hermaphroditic duct.

Etymology.

Named after the recent efforts supporting equal marriage rights in Taiwan and around the world. Derived from “diversus” (Latin for different) and “familia” (Latin for family), adjective of feminine gender.

Distribution.

Endemic to Taiwan and is currently known from I-Lan and Hualian Counties. Aegista diversifamilia sp. n. is absent from Gueishan Island based on our field investigation ( Huang et al. 2013). The northernmost distribution is limted by the Lanyang River. We suggest that the Lanyang River is the putative biogeographic boundary between Aegista diversifamilia sp. n. and Aegista subchinensis .

Ecology.

Live snails are generally found on the ground or under leaf litter in shady, moist environments in lowland hardwood forests (Figure 8). Eggs white and round, approximately 3 mm in diameter with 20-30 eggs in each spawn (personal observation of reared snail in laboratory).

Remarks.

Aegista diversifamilia sp. n. can be distinguished from Aegista subchinensis by its overall larger shell width (1.98-3.24 cm), whorl width and aperture, more depressed shell, and wider umbilicus (0.77-1.59 cm) and larger apex angle (148.56°-165.02°) (see Suppl. material 1, Table S1). For the genital morphology, Aegista diversifamilia sp. n. was distinguished from Aegista subchinensis by thicker and about three times logner albumen gland, larger and about two times longer dart-sac of auxiliary copulatory organ and epiphallial flagellum. The length of hermaphroditic duct/ albumen gland ratio was three times larger in Aegista diversifamilia sp. n. than in Aegista subchinensis .

The morphological divergence between the eastern and the western Aegista subchinensis was firstly noticed by Lee and Chen (2003), who found that the shells from the western population were roughly one third smaller than those from the eastern population. When newly describing Aegista caperata , Lee and Wu (2004) suggested the presence of cryptic species within Aegista subchinensis from different sides of the CMR. Wen and Hwang (2014) compared reproductive system between subgenus Aegista and Plectotropis . Aegista (Aegista) subchinensis and Aegista (Plectotropis) mackensii were dissected as representative species. Wen and Hwang (2014) mentioned there were two lobes of mucus glands of Aegista subchinensis . According to the shell masurements, sampling locality (Xiulin Township, Hualien County) and the illustration of genital morphology figure 1 of Aegista subchinensis was actually the nominal new species presented here, Aegista diversifamilia sp. n. It might suggested that the number of lobes of mucus glands is a variable characteristic in Aegista diversifamilia sp. n.