Rhiostoma ebenozostera Tongkerd & Panha, 2023
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publication ID |
https://dx.doi.org/10.3897/zookeys.1142.90097 |
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publication LSID |
lsid:zoobank.org:pub:A1129EE5-0F99-41CF-B73A-E771B66E2486 |
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persistent identifier |
https://treatment.plazi.org/id/24A470B8-4449-4FF9-802F-AC4DC0BCBB11 |
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taxon LSID |
lsid:zoobank.org:act:24A470B8-4449-4FF9-802F-AC4DC0BCBB11 |
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treatment provided by |
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scientific name |
Rhiostoma ebenozostera Tongkerd & Panha |
| status |
sp. nov. |
11. Rhiostoma ebenozostera Tongkerd & Panha sp. nov.
Figs 18 View Figure 18 , 29 View Figure 29 , 32D View Figure 32
Type material.
Holotype CUMZ 4703 (cW 19.4 mm, cH 11.1 mm, dL 13.7 mm; Fig. 29A View Figure 29 ). Paratypes CUMZ 3887 (228 shells), CUMZ 3889 (53 adults + 25 juveniles; Fig. 29C View Figure 29 ), CUMZ 4704 (2 shells; Figs 29B View Figure 29 , 32D View Figure 32 ), CUMZ 4766 (99 adults + 24 juveniles), NHMUK 20220439 (5 shells), and SMF 368674 (5 shells). All paratypes are from the type locality.
Type locality.
Tham Pha Poo, Muang District, Loei Province, Thailand (17°34'45.1"N, 101°42'36.2"E). Dry dipterocarp forest on limestone hill.
Other material examined.
Thailand: Wat Tham Pha Ban, Chiangkan, Loei: CUMZ 4444. Phu Pha Lom, Muang, Loei: CUMZ 10013. Wat Tham Phu Pha Lom, Muang, Loei: CUMZ 4443. Tham Khuha Waree, Wang Sapung, Loei: CUMZ 3925, 3946. Tham Pha Fang, Wang Sapung, Loei: CUMZ 10155. Khao Wangpha, Na Wang, Nongboa Lumphu: CUMZ 3935. Tham Suwannakhuha, Na Wang, Nongboa Lumphu: CUMZ 4765 (Fig. 29E View Figure 29 ). Wat Paphaya, Suwannakhuha, Nongboa Lumphu: CUMZ 10031. Wat Suwannakhuha, Ban Nasi, Suwannakhuha, Nongboa Lumphu: CUMZ 3889, 3933, 10021. Wat Phu Poon, Lomkao, Phetchabun: CUMZ 10211 (Fig. 29D View Figure 29 ). Tham Poo Loup, Chum Phae, Khon Kaen: CUMZ 3931. Tham Nennoi, Chum Phae, Khon Kaen: CUMZ 10015. Tham Phayanakarat, Chum Phae, Khon Kaen: CUMZ 10025. Phu Wiang, Wiang Kao, Khon Kaen: CUMZ 10166/1, 10166/2 (Fig. 29F View Figure 29 ) .
Diagnosis.
Shell medium, thick and depressed. Detached whorl medium in length, curved, and slightly descending. Breathing device tubular. Broad dark brown spiral band on periphery present.
Differential diagnosis.
Rhiostoma ebenozostera sp. nov. can be distinguished from all other recognised Rhiostoma species by having a prominent wide dark brown to black peripheral band. This colour pattern persists in all populations recognised for this species. Regardless of the peripheral band, this new species can be distinguished from R. housei in having straight and slender tubular breathing device, and relatively longer detached whorl. In contrast, R. housei has a stout and curved tubular breathing device and relatively shorter detached whorl.
Description.
Shell. Shell medium, cW 17.7-22.6 mm, cH 9.4-12.1 mm, thick, and sub-discoidal to discoidal shape; detached-whorl length 8.5-14.5 mm. Apex acute; spire nearly flat to elevated. Whorls 4 to 5, convex, increasing regularly; suture wide and shallow; last whorl rounded and stout. Detached whorl medium in length, approximately the same length as apertural width, curved and descending. Shell surface with fine growth lines. Periostracum thin, corneous, and transparent. Shell colour uniformly brownish or with pattern of dark brown blotches, and faded on ventral shell surface; dark spiral band on periphery always present and broad. Peristome circular and double; lip thickened, expanded and multi-layered. Aperture opened sub-ventrally. Breathing device tubular, perpendicular to detached whorl and its tip attached to preceding whorl; outer lip forming long and closed tube and located just behind apertural lip; inner lip with deep incision or small hole inside aperture. Umbilicus widely opened and deep. Operculum calcareous, cup-shaped, and multispiral (Fig. 29 View Figure 29 ).
Radula. Teeth arrangement and shape are similar to those of R. housei . Central tooth with large central cup and two lateral cusps on each side. Lateral teeth composed of three cusps; central cusp large, with convex tip, and flanked by small pointed tips of one outer cusp and one inner cusp. Marginal teeth each consisting of three pointed cusps (Fig. 32D View Figure 32 ).
Etymology.
The specific name ebenozostera is derived from the two Greek words ebenos meaning black colour, and zoste meaning girdle or belt. This name refers to the prominence of a dark, wide, peripheral band, which is the distinguishing character of this species.
Distribution.
This new species has narrow distribution; it is known from several limestone outcrops in dry deciduous forests of Loei, Nong Bua Lam Phu, and Khonkaen provinces (Fig. 18 View Figure 18 ).
Remarks.
The specimens from Nong Bua Lam Phu possess a stout shell, slightly shorter detached whorl, and paler shell colour (Fig. 29E View Figure 29 ) than the typical population. However, a prominent broad, dark, peripheral band suggests that they are conspecific.
No known copyright restrictions apply. See Agosti, D., Egloff, W., 2009. Taxonomic information exchange and copyright: the Plazi approach. BMC Research Notes 2009, 2:53 for further explanation.