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Namkongnaia inkhavilayi gen. et sp. nov.

urn:lsid:zoobank.org:act: 622F7788-F0A4-449D-814A-5B49CD20B228

Figs. 3 , 4A–B ; Tables 1 , 3

Pilsbryoconcha lemeslei – Brandt 1974: 263 , pl. 18 fig. 22 (in part, only records from “Nang Rong (Prov. Burirum)”, collectingCountryThailand ) [non Anodonta lemeslei Morelet, 1875 ].

Etymology

This new species is dedicated to our colleague and distinguished malacologist, Dr Khamla Inkhavilay, from the National University of collectingCountryLaos .

Type material

Key Value
id 3B741208FFBD6F19FF76ECBBFDB0ED17
ID-GBIF-Occurrence 3392107312
collectedFrom sold by local people
collectorName E. Jeratthitikul & K. Wisittikoson & A. Fanka & N. Wutthituntisil & P. Prasankok
country Laos
latitude 17.13674
location Kammoune Province
longitude 104.98591
municipality Bunghona Market
specimenCode MUMNH-UNI2831
specimenCount 1
typeStatus holotype
typeStatusHolotype collectingCountryLAOSlocationKammoune Province , collectingMunicipalityBunghona Market , quantity7 km N of Xe Bangfai River ; geoCoordinate17.13674° N , geoCoordinate104.98591° E ; collectorNameE. Jeratthitikul , collectorNameK. Wisittikoson , collectorNameA. Fanka , collectorNameN. Wutthituntisil and collectorNameP. Prasankok leg.; sold by local people ; specimenCodeMUMNH-UNI2831 .

Fig. 3. Map showing distribution localities of Namkongnaia gen. nov. Boundaries of river basins follow Abell et al. (2008) .

Table 2. Average genetic divergence based on uncorrected p-distance of 660-bp COI gene fragment sequences of freshwater mussel genera in the tribe Pseudodontini (% ±S.E.).

Taxa 1. 2. 3. 4. 5. 6. 7.
1. Namkongnaia
gen. nov. 2. Monodontina 3. Sundadontina 11.02 ± 1.00 12.01 ± 1.05 12.06 ± 0.98
4. Bineurus 11.60 ± 1.19 11.90 ± 1.09 11.92 ± 1.09
5. Thaiconcha 11.81 ± 1.23 13.53 ± 1.21 11.97 ± 1.09 11.92 ± 1.29
6. Nyeinchanconcha 11.70 ± 1.25 12.58 ± 1.20 10.65 ± 1.00 10.75 ± 1.24 12.80 ± 1.37
7. Pilsbryoconcha 12.41 ± 1.15 11.85 ± 1.01 12.16 ± 1.02 10.93 ± 1.08 12.36 ± 1.22 11.44 ± 0.17
8. Pseudodon 12.42 ± 1.10 12.78 ± 1.06 13.13 ± 1.02 12.27 ± 1.10 13.35 ± 1.16 12.69 ± 1.17 12.23 ± 01.01

Key Value
id 3B741208FFBA6F1EFF76ECA3FB19ECC0
ID-GBIF-Occurrence 3392107317
collectedFrom sold by local people
collectionCode UNI
collectorName E. Jeratthitikul & K. Wisittikoson & A. Fanka & N. Wutthituntisil & P. Prasankok
country Laos
latitude 17.13674
location LAOS
longitude 104.98591
municipality Bunghona Market
specimenCode MUMNH-UNI2832, UNI2835
specimenCount 5
typeStatus paratype
typeStatusParatypes collectingCountryLAOSspecimenCount5 shells ; same collection data as for holotype; specimenCodeMUMNH-UNI2832 to specimenCodeUNI2835
.

Other material

Key Value
id 3B741208FFBA6F1EFF21ED3BFB4BED7C
ID-GBIF-Occurrence 3392107302
collectorName R. Brandt
country Laos
location Nong Njang
specimenCode BMNH-MP-D262
specimenCount 2
collectingCountryLAOSspecimenCount2 shells ; locationNong Njang , N of Vientiane ; collectorNameR. Brandt leg.; specimenCodeBMNH-MP-D262
Key Value
id 3B741208FFBA6F1EFB01ED3BFC86ED59
ID-GBIF-Occurrence 3392107303
collectorName R. Brandt
specimenCode ANSP-H19043
specimenCount 1
specimenCount1 shell ; Nong Bua Thong near Vientiane ; collectorNameR. Brandt leg.; specimenCodeANSP-H19043
Key Value
id 3B741208FFBA6F1EFCF3ED56FDDDEDB5
ID-GBIF-Occurrence 3392107309
collectionCode MCZ
collectorName R. Brandt
specimenCode MCZ-280932
specimenCount 2
specimenCount2 shells ; Nong Bua Thong near Vientiane ; collectorNameR. Brandt leg.; specimenCodeMCZ-280932
Key Value
id 3B741208FFBA6F1EFDB1ED72FABFEDB5
ID-GBIF-Occurrence 3392107307
collectionCode SMF
collectorName R. Brandt
specimenCode SMF-258771
specimenCount 2
specimenCount2 shells ; Nong Bua Thong near Vientiane ; collectorNameR. Brandt leg.; specimenCodeSMF-258771
Key Value
id 3B741208FFBA6F1EFF51EDADFC12ED96
ID-GBIF-Occurrence 3392107320
collectionCode SMF
collectorName R. Brandt
location Nong Bua Thong
specimenCode SMF-319294
specimenCount 2
stateProvince Vientiane
specimenCount2 shells ; locationNong Bua Thong , collectingRegionVientiane ; collectorNameR. Brandt leg.; specimenCodeSMF-319294
Key Value
id 3B741208FFBA6F1EFC6CEDADFDE6EDF3
ID-GBIF-Occurrence 3392107310
collectorName R. Brandt
specimenCode ANSP-H19044
specimenCount 1
specimenCount1 shell ; Bang Jian near Vientiane ; collectorNameR. Brandt leg.; specimenCodeANSP-H19044
Key Value
id 3B741208FFBA6F1EFDD2EDC8FB38EDF2
ID-GBIF-Occurrence 3392107304
specimenCode MNHN-MP-3154
specimenCount 6
specimenCount6 shells ; Nang Njang near Vientiane ; specimenCodeMNHN-MP-3154
Key Value
id 3B741208FFBA6F1EFA8CEDC8FC50EA2F
ID-GBIF-Occurrence 3392107318
collectorName R. Brandt
specimenCode MNHN-MP-3157
specimenCount 4
specimenCount4 shells ; Nang Njang near Vientiane ; collectorNameR. Brandt leg.; specimenCodeMNHN-MP-3157
Key Value
id 3B741208FFBA6F1EFC2DEDEBFE56EA08
ID-GBIF-Occurrence 3392107301
collectionCode SMF
collectorName R. Brandt
specimenCode SMF-225743
specimenCount 3
specimenCount3 shells ; swamp near Pakse ; collectorNameR. Brandt leg.; specimenCodeSMF-225743 .

Key Value
id 3B741208FFBA6F1EFF21EA40FBF6EAA4
ID-GBIF-Occurrence 3392107316
collectorName E. Jeratthitikul & K. Wisittikoson & P. Prasankok
country Thailand
county Tha Uthen
latitude 17.56221
location Thuai River
longitude 104.6089
municipality Tha Uthen
specimenCode MUMNH-UNI2706
specimenCount 1
stateProvince Nakhon Phanom
collectingCountryTHAILANDspecimenCount1 shell ; collectingRegionNakhon Phanom , collectingCountyTha Uthen , collectingMunicipalityTha Uthen , locationThuai River ; geoCoordinate17.56221° N , geoCoordinate104.60890° E ; collectorNameE. Jeratthitikul , collectorNameK. Wisittikoson and collectorNameP. Prasankok leg.; specimenCodeMUMNH-UNI2706
Key Value
id 3B741208FFBA6F1EFBC7EA63FD60EAE2
ID-GBIF-Occurrence 3392107306
collectorName E. Jeratthitikul & K. Wisittikoson
country Thailand
county Sawang Daen Din
latitude 17.3957
location Songkhram River
longitude 103.30048
municipality Bong Tai
specimenCode MUMNH-UNI0318
specimenCount 1
stateProvince Sakon Nakhon
specimenCount1 shell ; collectingRegionSakon Nakhon , collectingCountySawang Daen Din , collectingMunicipalityBong Tai , locationSongkhram River ; geoCoordinate17.39570°N , geoCoordinate103.30048°E ; collectorNameE. Jeratthitikul and collectorNameK. Wisittikoson leg.; specimenCodeMUMNH-UNI0318
Key Value
id 3B741208FFBA6F1EFD5DEAB9FEBDEADF
ID-GBIF-Occurrence 3392107321
collectionCode R
collectorName R. Brandt
country Thailand
location Huai Tadjek
municipality Nang Rong
specimenCode USNM-786219
specimenCount 1
stateProvince Buriram
specimenCount1 shell ; collectingRegionBuriram , collectingMunicipalityNang Rong , locationHuai Tadjek ; collectorNameR. Brandt leg.; specimenCodeUSNM-786219
Key Value
id 3B741208FFBA6F1EFE0DEAD5FB30EADE
ID-GBIF-Occurrence 3392107314
collectionCode R
collectorName R. Brandt
country Thailand
location Huai Tadjek
municipality Nang Rong
specimenCode SMF-220822
specimenCount 1
stateProvince Buriram
specimenCount1 shell ; collectingRegionBuriram , collectingMunicipalityNang Rong , locationHuai Tadjek ; collectorNameR. Brandt leg.; specimenCodeSMF-220822
Key Value
id 3B741208FFBA6F1EFA8FEAD5FD94EB3B
ID-GBIF-Occurrence 3392107315
collectionCode SMRL
collectorName Nang Rong
country Thailand
location Buriram
specimenCode SMRL-2662
specimenCount 4
stateProvince Buriram
specimenCount4 shells ; collectingRegionBuriram , collectorNameNang Rong ; specimenCodeSMRL-2662
Key Value
id 3B741208FFBA6F1EFDEAEAF0FABDEB3B
ID-GBIF-Occurrence 3392107319
collectorName Nang Rong
country Thailand
location Buriram
specimenCode ANSP-H19042
specimenCount 1
stateProvince Buriram
specimenCount1 shell ; collectingRegionBuriram , Huai Ta Djek near Nang Rong ; specimenCodeANSP-H19042
.

Description

Shell medium-sized, length quantity80.9–102.2 mm , height quantity26.2–37.2 mm , width quantity13.6–19.1 mm ( Table 3 ). Shell rather thin, narrow and elongated (H/L ratio = 0.32–0.36), very inequilateral, compressed. Dorsal margin straight, anterior at the same level as posterior. Umbonal area eroded, not elevated. Anterior margin round; posterior margin elongated and rounded. Ventral margin almost straight, slightly curved upward posteriorly. Posterior ridges low, wide and obtuse, not prominent. Periostracum thin, greenish to dark brown, the eroded part coppery-brown. Shell surface with fine growth lines. Ligament very narrow. Hinge without dentition, posterior end of the hinge structure with V-shaped fossette. Anterior adductor muscle scar placed relatively far from the dorsal margin, shallow, ovate, fused with pedal retractor muscle scars; posterior adductor muscle scars very shallow, almost invisible. Pallial line very faint. Nacre whitish with cream tint near the umbo. Excurrent aperture smooth, shorter than incurrent. Incurrent with 1–2 rows of conical papillae, varying in length. Small epithelial folds form a fused bridge separating excurrent and incurrent aperture. Gills elongated and slightly ribbed. Anterior margin of inner gills slightly longer and wider than that of inner outer gills. Glochidia unknown.

Distribution

This new species appears to occur in the Lower Mekong watershed. In collectingCountryLaos , it was recorded from several locations near collectingRegionVientiane , Kammoune, and collectingRegionChampasak Provinces. In collectingCountryThailand , it is known from the Songkram and Mun river basins in the northeast region ( Brandt 1974 ).

Habitat

Specimens of the new species were bought on a local market near the Xe Bangfai River. However, specimens from the Thuai and Songkhram Rivers in collectingCountryThailand were found buried in the mud substrate of still water. Brandt (1974) also reported ponds as a general habitat of this species.

Remarks

The specimens recorded by Brandt (1974) from Nang Rong, collectingRegionBuriram , collectingCountryThailand (SMF-220822) show a shorter but wider shell and a relative rounded ventral margin. In addition, although the hinge area of this species has no dentition, the trace of a rudimentary pseudocardinal tooth is seen as a very tiny tubercle in some individuals.