Sermyla kupaensis, Lentge-MAAss & Neiber & Gimnich & Glaubrecht, 2021

Lentge-MAAss, Nora, Neiber, Marco T., Gimnich, France & Glaubrecht, Matthias, 2021, Evolutionary systematics of the viviparous gastropod Sermyla (Gastropoda: Cerithioidea: Thiaridae), with the description of a new species, Zoological Journal of the Linnean Society 192 (3), pp. 736-762 : 753-754

SERMYLA KUPAENSIS SP. NOV.

( FIGS 1P–T , 4 , 11A, B )

Zoobank registration: urn: lsid: zoobank. org:act: 14715EED-3C76-4F47-AD05-9DE6F6F8127D

Etymology: For the type locality, the township of Kupa in south-western Sulawesi.

Type material: Holotype, Indonesia, Sulawesi, Kupa, stream E of road Makassar-Parepare , 4°7.567´S 119°37.426´E ( MZB Gst. 12.191 w) ; 16 paratypes from the type locality ( ZMB 190982) ; 88 paratypes from the type locality ( ZMB 191388 w) ; 80 paratypes from the type locality ( MZB Gst. 12.192 w) ; five paratypes from the type locality ( ZMH 94335 w) .

Additional material examined: Indonesia: Sulawesi: Makassar, 5°8′ S 119°25′ E ( ZMB 210079, 210082).

Diagnosis: Shell as in S. riquetii . Veliger larvae (> 1000) are released from the subhaemocoelic brood pouch of the female.

Description

Shell ( Fig. 1P–T ): The shell of S. kupaensis cannot be distinguished from that of S. riquetii .

Reproduction: Female S. kupaensis individuals were found to contain only veliger larvae (> 1000) in their brood pouches, i.e. the species has an ovoviviparous reproductive strategy.

Juvenile shell ( Fig. 5B ): Since we did not observe any shelled juveniles in the brood pouch, we display the image of a veliger larvae with an already clearly visible operculum. We are not able to make any further statements concerning the juvenile shell of S. kupaensis .

Radula ( Fig. 11A, B ): Typical, as in other Thiaridae (see: Glaubrecht et al., 2009). Rachidian with a subtriangular central denticle with broadly rounded tip and three smaller denticles on either side of central denticle, also triangular in shape with a rounded tip. Central denticles of lateralia broader and rounder than seen in other thiarids, flanked by two relatively large denticles forming a pronounced wing-shaped plate on the inner side projecting towards the central teeth. Marginal teeth with six to seven denticles.

Ecology: This species lives in water bodies above tidal influence, although empty shells may be washed downstream. Near Kupa it was found exclusively at elevations of several dozen metres above the sea level on an elevated plateau with muddy pools of stagnant water adjacent to the river course, but not in the running stream itself. The species seems to prefer these pools with stagnant water over running water, apparently due to the richer muddy substrate it lives in and feeds from.

Distribution: It is known only from the type locality. Shells found in Makassar further south on Sulawesi along the same coast line are probably also attributable to this species.

Remarks

Shells of S. kupaensis cannot be distinguished from S. riquetii but are, on average, slightly larger than samples from Thailand, Vietnam and Bali, for which an euviviparous reproductive strategy could be confirmed here. The different reproductive strategy, i.e. ovoviviparity, and the divergent mitochondrial haplotypes, suggest that the specimens from Sulawesi represent a distinct evolutionary lineage. Specimens of S. carbonata from Australia, which has a euviviparous reproductive strategy, usually have a higher spire than S. kupaensis . Moreover, some populations of S. carbonata can readily be distinguished by their weaker shell sculpture.

Figures

Figure 1. A–AB, shell morphology of Sermyla: A–O, Sermyla riquetii; P–T,Sermyla kupaensis; U–AB, Sermyla carbonata.A, syntype of Sermyla riquetii (Grateloupe, 1840), ‘Batavia’ (BMNH 1907.11.22.40); B, syntype of Sermyla riquetii (Grateloupe, 1840), ‘Batavia’ (BMNH 1907.11.22.41); C, syntype of Melania harpula Dunker, 1844 (ZMB 109669); D, syntype of Melania mitra Dunker, 1844 (ZMB 109670); E, original drawing of Melania semicostata Philippi 1847; F, syntype of Melania tornatella Lea & Lea, 1851 (BMNH 1978155); G, syntype of Melania sculpta Souleyet, 1852 (BMNH 1854.7.24.381); H, holotype of Sermyla kowloonensis Chen, 1943 (USNM 48041); I, S. riquetii from Bali, Gumbrih River (ZMB 106474-3); J, S. riquetii from Thailand, Puek Tian Beach (ZMB 107883-11); K, S. riquetii from Thailand, Perchaburi (ZMB 127817-2); L, S. riquetii from Thailand, Samut Songkhram (ZMB 127818-2); M, S. riquetii from Vietnam, Hue (ZMB 114421–5); N, S. cf. riquetii from Australia: QLD, Caloundra (AMS C.3215-1); O, S. cf. riquetii from Australia: QLD, Caloundra (AMS C.3215-2); P, holotype of Sermyla kupaensis from Indonesia, Kupa River (MZB Gst. 12.191); Q, paratype of Sermyla kupaensis ZMB 191388-4); R, paratype of Sermyla kupaensis (ZMB 191388-10); S, paratype of Sermyla kupaensis (ZMB 191388-5); T, paratype of Sermyla kupaensis (ZMB 191388-7); U, syntype of Sermyla carbonata (Reeve, 1859), ‘Port Essington’ (BMNH 2001.0762); V, syntype of Melania venustula Brot, 1877, ‘Port Denison’ (MNHG, no number); W, holotype of Sermylasma prognata Iredale, 1943, Australia, Victoria River (BMNH 1857.9.30.8-1); X, S. carbonata, Australia: Bundara Sinkhole (BES 10048); Y, S. carbonata, Australia, Howard Springs (ZMB 107630–2); Z, S. carbonata, Australia, Roper River (ZMB 107616-1); AA, S. carbonata, Australia, Roper Bar (ZMB 192017-1); AB, S. carbonata, Australia, Norman River (107209-5).

Figure 4. Shape differences of populations of S. riquetii, S. carbonata and S. kupaensis. Principle component analysis (PCA) for the configuration of 15 landmarks of S. kupaensis from Sulawesi, S. riquetii from Bali, Vietnam and Thailand, S. cf. riquetii from Australia, as well as S. carbonata in the different drainage systems of Australia. Five-pointed star: syntype of S. riquetii; nine-pointed star: syntypes of S. carbonata; six-pointed stars: syntypes of M. venustula; triangle tip down: holotype of S. prognata.

Figure 5. Morphological differences of Sermyla kupaensis, S.riquetii and S. carbonata populations. A, boxplots for the height measurements of Sermyla kupaensis, S.riquetii and S. carbonata from the different sampling locations and river systems. Five-pointed star: syntypes of S. riquetii; six-pointed stars: syntypes of M. venustula; triangle tip down: holotype of S. prognata; nine-pointed star: syntypes of S. carbonata. B, boxplots for the total amount of juveniles inside the brood pouch of S.riquetii and S. carbonata from different sampling locations and drainage systems, as well as a veliger larva from Sermyla kupaensis for comparison.

Figure 11. Anatomy of the radula in Sermyla. A, rachis and lateralia of Sermyla kupaensis (ZMB 191388). B, marginalia of Sermyla kupaensis (ZMB 191388). C, rachis and lateralia of S. riquetii (BMNH 2403). D, marginalia of S. riquetii (BMNH 2403). E, rachis and lateralia of S. carbonata (ZMB 106700). F, marginalia of S. carbonata (ZMB 106700).