Landouria circinata, Nahok & Tumpeesuwan & Tumpeesuwan, 2021
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publication ID |
https://doi.org/ 10.5852/ejt.2021.767.1495 |
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publication LSID |
lsid:zoobank.org:pub:9F019E02-95E7-4B6A-B5BC-01F8E26F3466 |
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DOI |
https://doi.org/10.5281/zenodo.5528092 |
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persistent identifier |
https://treatment.plazi.org/id/B434E62B-9FA6-43FB-B27F-A4B1B0413225 |
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taxon LSID |
lsid:zoobank.org:act:B434E62B-9FA6-43FB-B27F-A4B1B0413225 |
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treatment provided by |
Felipe |
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scientific name |
Landouria circinata |
| status |
sp. nov. |
Landouria circinata View in CoL sp. nov.
urn:lsid:zoobank.org:act:B434E62B-9FA6-43FB-B27F-A4B1B0413225
Figs 3A View Fig , 4A View Fig , 5A View Fig , 6A–C View Fig ; Tables 1–4 View Table 1 View Table 2 View Table 3 View Table 4
Landouria sp. – Tanmuangpak et al. 2012: 7, 12, fig. 5y. — Tanmuangpak 2016: 125–126, figs 4.74– 4.75.
Landouria sp.4 – Ounchareon 2015: 40–42, figs 4.12, 4.13, 5.1, 5.7.
Landouria sp.2 – Yingkhamhang 2016: 21–22, 39–41, 43–45, 47–48, figs 4.3–4.4, 4.21b, 4.22c, 4.23b, 5.1b, 5.2b.
Diagnosis
Shell brownish-corneous, periphery angular, sharply keeled. Flagellum circinate; penis cylindrical and longer than vagina; base of gametolytic sac thick and stout. Radula with unicuspid short tongue-shaped central teeth.
Etymology
The Latin word ‘ circinata ’ refers to the coiled or curled flagellum which resembles the circinate vernation of a fern shoot.
Type material
Holotype THAILAND • shell (SH = 8.2 mm, SW = 13.8 mm, AH = 5.1 mm, AW = 5.1 mm, UW = 3.8 mm); Loei Province, Mueang District, Phu Pha Lom Forest Park; 17°33′18.03″ N, 101°52′6.71″ E; alt. 415 m; 7 Jun. 2017; B. Nahok and U. Chanlabut leg.; NHMSU-00023 . ( Fig. 3A View Fig ) GoogleMaps
Paratypes THAILAND • 11 shells, 43 living specs; same collection data as for holotype; GenBank No. MN449401 View Materials and MZ435746 View Materials ; NHMSU-00024 GoogleMaps .
Description
SHELL ( Fig. 3A View Fig , Table 1 View Table 1 ). Dextral, medium sized, conical-lenticular, with six slightly convex whorls. Suture shallow. Apex obtuse, depressed and low-conical. Light brown at 4 early whorls, dark brown at 2 last whorls. Sharply keeled, with pale brown band on the peripheral keel. Umbilicus very deep and wide. Aperture lip somewhat thickened, rounded rhombic.
GENITAL SYSTEM (n = 3) ( Fig. 5A View Fig , Table 4 View Table 4 ). Penis very long, cylindrical, and curled, divided into two portions of equal length, internally with parallel, transverse folds, containing a short, rather rounded verge. Epiphallus short cylindrical, thinner than the penis. Flagellum slightly crenated and curled up, resembling the circinate vernation of a fern shoot, with thin grooves internally and tubercles on its surface at the end, internally with transverse robust folds. Vas deferens is a slender, cylindrical tube, thicker at the end where it connects to free oviduct; entering flagellum basally. Vagina less than half as long as penis, internally with four thin longitudinal pilasters. Free oviduct shorter than vagina. Gametolytic sac thickened at base, stout and gradually tapering distally to form a slender distal tube ending in a balloonshaped, medium-sized sac. Prostate gland very long, uterus long and swollen.
RADULA (n = 3). Comprises 95 transverse rows with 57–61 teeth per row; radular formula: (20)-(8–10)- 1-(8–10)-(20). Central tooth symmetric, unicuspid, tongue-shaped; lateral teeth longer than central tooth and oblique, unicuspid, tongue-shaped ( Fig. 6A View Fig ). Marginal teeth tricuspid with medium-sized endocone; mesocone rather large, with rounded cusp; ectocone triangular ( Fig. 6B–C View Fig ).
Remarks
Landouria circinata sp. nov. resembles L. strobiloides (see Tumpeesuwan & Tumpeesuwan 2019: fig. 3) in shell morphology, L. circinata sp. nov. has a smaller shell, a shallower suture, and darker peripheral zone than L. strobiloides ( Table 4 View Table 4 , Fig. 3A View Fig ). Its central and lateral radular teeth are unicuspid and tongueshaped, whereas they are lanceolate in L. strobiloides ( Table 4 View Table 4 , Fig. 6A View Fig ). The unique characters of L. circinata sp. nov. are its circinate flagellum and its penis that is much longer than the vagina ( Fig. 5A View Fig ), whereas L. strobiloides has a strobilus-like flagellum and a penis that is shorter than the vagina.
Distribution
Landouria circinata sp. nov. is known only from the type locality.
Table 4. Comparison of shells, radulae, and genital systems of Landouria spp. from northeastern Thailand. References: 1 = Tumpeesuwan & Tumpeesuwan (2019); 2 = Nahok (2020); 3 = this study. *In Tumpeesuwan & Tumpeesuwan (2019) indicated the number of teeth per row in Landouria strobiloides varies from 3 to 53. This lowest row has only 3 teeth. It is the uppermost row, probably lacerated and peel off. Unfortunately, we could not re-checked the complete specimens in this time being, so, this point need further investigation and proof.
| Characters | L. strobiloides | L. circinata sp. nov. | L. tuberculata sp. nov. | L. trochomorphoides sp. nov. | L. chloritoides sp. nov. | L. elegans sp. nov. | L. diplogramma |
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| Shell: | |||||||
| Shell height (mm) | 7.10–9.60 | 5.60–8.10 | 7.00–9.60 | 7.60–11.30 | 6.10–12.00 | 6.00–10.00 | 6.00–8.70 |
| Shell colour | pale brown | brownish-corneous | red brown | brownish-corneous | red brown | brownish-corneous | whitish-corneous |
| Suture | deep | shallow | slightly deep | shallow | deep | shallow | shallow |
| Peripheral band | dark brown | pale brown | absent | brown | absent | dark brown | pale brown |
| Peripheral keel | sharp | sharp | moderate | sharp | weak | sharp | very weak |
| Sculpture | absent | absent | tubercles | scaly | absent | absent | absent |
| Number of whorls | 5½ | 6 | 6½ | 6 | 6½ | 6 | 5½ |
| Radula: | |||||||
| Number of rows | 100 | 93–95 | 126–130 | 107–111 | 125–129 | 110–114 | 121–125 |
| Number of teeth in each row | 3*–53 | 55–63 | 79–87 | 65–73 | 75–83 | 69–77 | 61–69 |
| - Lateral teeth | 8–10 | 8–10 | 11–13 | 8–10 | 11–13 | 12–14 | 7–9 |
| - Marginal teeth | 15–17 | 19–21 | 28–30 | 24–26 | 26–28 | 22–24 | 23–25 |
| Central tooth | elongate lanceolate | tongue-shaped | slender lanceolate | short lanceolate | lanceolate | tongue-shaped | triangular |
| Genital system: | |||||||
| Penis | short, slightly stout | long cylindrical | swollen | long slender | very large and stout | long cylindrical | swollen |
| Flagellum | strobilus-shaped | circinate | short protrusion | slender towards tip | narrow ovate | water drop-shaped | short protrusion |
| Basal part of gametolytic sac | swollen | thick and stout | rhin | thin | thick | stout | thick |
| References | 1, 2 | 2, 3 | 2, 3 | 2, 3 | 2, 3 | 2, 3 | 2, 3 |
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.
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SuperFamily |
Helicoidea |
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Family |
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Genus |
Landouria circinata
| Nahok, Benchawan, Tumpeesuwan, Sakboworn & Tumpeesuwan, Chanidaporn 2021 |
Landouria sp.
| Tanmuangpak K. 2016: 125 |
| Tanmuangpak K. & Tumpeesuwan C. & Tumpeesuwan S. 2012: 7 |