Nagyelma n. gen. for Ennea aliena Bavay and Dautzenberg, 1912 (Gastropoda: Eupulmonata: Streptaxidae)

Nagyelma n. gen. is erected for the northern Vietnamese Ennea aliena Bavay and Dautzenberg, 1912. The most closely related genus is probably Elma H. Adams, 1866, which also has a high-spired shell but differs from the new genus in the absence of a parietal tooth, the pointed-ovoid shell shape, and the penial sheath, which covers only half of the penis.


Materials and Methods
Ten to 30 photographs were taken of each shell using Keyence LHX5000 digital microscope and merged to create a single image using Photoshop. The ethanol-preserved specimen was dissected under a Zeiss stereomicroscope, and photographs were taken using a Keyence LHX5000 digital microscope. Abbreviations: HA: Collection András Hunyadi, (Budapest, Hungary); HE: Collection Christa Hemmen (Wiesbaden, Germany); HNHM: Hungarian Natural History Museum (Budapest, Hungary); MNHN: Muséum National d'Histoire Naturelle (Paris, France).

Subfamily Streptaxinae Gray, 1860
Remarks: In an earlier publication, we discussed the systematic position of Elma (Páll-Gergely et al., 2015), which has similar anatomical traits to that of Nagyelma n. gen. Based on the morphology of the reproductive anatomy, Elma can be classified either in the in the subfamily Streptaxinae or in Gibbinae sensu Schileyko (2000). The former group ranges through tropical Asia, Africa and South America. In contrast, the Gibbinae (at least the group probably containing Gibbus Montfort, 1810, see Rowson et al., 2010 andPáll-Gergely et al., 2015) are mostly distributed in the Seychelles and the Mascarene islands, while the extinct type genus Gibbus is known form Mauritius. An Indoartemon Forcart, 1946 species from Sri Lanka clustered together with the South American Streptartemon Kobelt, 1905, andStreptaxis Gray, 1837 in the phylogenetic tree of Rowson et al. (2010). Indoartemon ranges to SE Asia, and several genera of similar conchological and anatomical traits inhabit that area. Thus, it is highly probable that at least some of the Southeast Asian streptaxid genera are members of Streptaxinae. Accordingly, it is more likely that Elma and Nagyelma n. gen. belong to the Streptaxinae than to the Gibbinae. Nagyelma Páll-Gergely, n. gen. Bavay and Dautzenberg, 1912. Diagnosis: Shell cylindrical, apex domed, surface glossy with fine ribs or simply a mamillated suture; aperture subcircular with pointed sinulus, peristome almost discontinuous, parietal callus only with thin calcareous layer; parietal lamella short and relatively low; upper margin of aperture curved backwards. Penis slender, long, its entire length covered by a penial sheath, internally with brown papillae bearing brown hooks; vas deferens enters penis after forming a loop under the penial sheath; penial retractor muscle inserts at the penis-vas deferens junction; vagina relatively long, internally with elevated folds converging towards atrium, and tiny horizontally arranged tiny pockets.

Type species: Ennea aliena
Differential diagnosis: Nagyelma n. gen. is probably most closely related to Elma (Fig. 1A-C; see Varga, 2012 andPáll-Gergely et al., 2015), which is similar in shell size and sculpture. However, shells of Elma species are all pointed-ovoid, whereas Nagyelma n. gen. is clearly ovoid with a blunt (domed) apical part. Furthermore, Elma species lack the short parietal lamella present in Nagyelma n. gen. Regarding the reproductive anatomy, the bursa copulatrix starts in a more proximal position in Elma, making the vagina shorter than in Nagyelma n. gen. The penial sheath covers only the distal half of the penis in Elma, whereas the entire penis is covered in Nagyelma n. gen.
Sinoennea is characterized by numerous (mostly four), apertural barriers (1 parietal, 2 palatal, 1 columellar), and they are built during the juvenile stages as well. In contrast, Nagyelma n. gen. has only a weak, short parietal lamella, and no apertural dentition is built during the juvenile stage.
Etymology: This new genus is dedicated to Barnabás Nagy (1921-2020), a prominent agrozoologist and orthopterologist, who worked in our institute for 63 years. The generic name Nagyelma is a combination of the family name Nagy (pronunciation: ) and Elma, referring to the probably most closely related genus. Grammatical gender: feminine.
Remarks: The African Ennea, in which N. aliena has been classified, is certainly not closely related to N. aliena due to morphological dissimilarities and biogeographical reasons. The most closely related genus is the also Southeast Asian Elma. Nagyelma n. gen. is erected here in order to avoid Elma becoming a wastebasket taxon (Páll-Gergely, 2017). The reproductive anatomy of Elma indicates that it does not belong to the Diapheridae, but to the Streptaxidae, although its classification in one of the subfamilies defined by Schileyko (2000) (Bavay and Dautzenberg, 1912). Note that the ureter has been broken during preparation (A).
Abbreviations We examined newly collected samples from four sites. The samples Vn12-225 and Vn12-269 are situated close to each other in central Thanh Hóa Province, and possess glossy shells, some with a mamillated suture (Fig. 1E). The sample 2020/38 was collected ca. 23 km southeast from the first two sites, and the shells are somewhat finely ribbed (Fig. 1F). The sample Vn12-268, which was collected ca. 20 km further southeast (ca. 86 km from the first two sites) is also ribbed (Fig. 1G). At the moment we consider this to be intraspecific variation.
Pallial complex ( Fig. 2A-B): Sigmurethrous, similar to that of Discartemon (see: Siriboon et al., 2014), with kidney sub-rectangular, being ca. twice as long as wide. Salivary gland (Fig. 2C): Single, soft, elongated, with two ducts leaving separately (rather than together as in Huttonella; Simone, 2013), each duct of even thickness throughout its length (overall similar to that of Elma, see Páll-Gergely et al., 2015). Fig. 4. Reproductive anatomy of Nagyelma aliena (Bavay and Dautzenberg, 1912). A: albumen gland and talon; B: inner wall of the vagina; C: inner wall of the penis (pointed, fleshy finger-like structure outlined) Genitalia (Figs. 3, 4): Atrium short; penis long, slender and cylindrical, nearly equally thick throughout; a yellowish knob situated slightly proximal from the centre of penis; between the atrium and the yellowish knob the inner penial wall is covered with scattered papillae, with brown penial hooks in each papilla (Fig. 4C); hooks are largest and more numerous towards the yellowish knob; hooks with sharp tips curved towards the atrium; an elongated, pointed, fleshy finger-like structure is situated on the penis wall at the yellow knob's position, reminiscent of, but not homologous with the penial verge of other stylommatophoran snails (outlined on Fig. 4C); a thin penial sheath present, covering entire penis and the descending and ascending part (loop) of the vas deferens; no epiphallic differentiation observed; vas deferens enters proximal end of penis laterally after forming a loop under the penial sheath; loop ending approximately at the middle of penial sheath, distal from the yellowish knob; diameter of vas deferens somewhat greater where it enters under penial sheath then elsewhere; penial retractor muscle long, thick, inserting at the penis-vas deferens junction and attached to the diaphragm. Vagina relatively long, slightly thicker towards spermoviduct; bursa copulatrix duct long, slender, with ovoid reservoir, reaching the albumen gland; free oviduct short, thicker than penis; inner wall of the vagina and the free oviduct with elevated folds converging towards atrium, and between the folds a longitudinal area with horizontally elongated tiny pockets (Fig. 4B); oviduct enlarged and folded; albumen gland relatively small, pointed; talon small ( Fig. 4A), thickened and curved.