Publication LSID: urn:lsid:zoobank.org:pub:185B2B6C-4199-4B7D-BA00-A2C1370167C3
INTRODUCTION
Bourciera Pfeiffer, 1852 is a genus of Helicinidae so far only known from the Andes of Ecuador and Northern Peru (PFEIFFER 1853, 1859, TROSCHEL 1856–1863, ADAMS 1870, ORTON 1871, MILLER 1879, COUSIN 1887, GERMAIN 1907, RAMÍREZ et al. 2003, CORREOSO 2008, BREURE & ARAUJO 2017, BREURE et al. 2022, RAMIREZ PEREZ & HAUSDORF 2022). Most recent literature figuring species of Bourciera only mentions B. helicinaeformis Pfeiffer, 1852 and B. fraseri (Pfeiffer, 1859) (e.g. CORREOSO 2008), but two additional species were described by MILLER (1879) from the Pilatón valley (Pichincha province, Ecuador): B. striatula Miller, 1879 and B. viridissima Miller, 1879. One of these species, B. viridissima, was considered identical to B. fraseri by GERMAIN (1907), even though the species appear to be distinct and are described from different type localities. Unfortunately it remains unknown in which institute Miller deposited his Neotropical type specimens, including the types of B. striatula and B. viridissima, even after an extensive search by BREURE (2019). In addition, odd new records of Amazonian Bourciera ssp. have been found while compiling an annotated checklist of all terrestrial gastropods in Ecuador (BREURE et al. 2022), raising questions about the limited distribution of the genus.
To clarify this, all species of Bourciera described in previous publications and their distribution are briefly discussed and figured in this paper. The identity of Bourciera viridissima Miller, 1879 is reestablished based on new records of living specimens and museum material. Additionally, six new species are described based on specimens from different regions in Ecuador and Peru and the genus is reported from Colombia for the first time. Other possibly new taxa encountered during this study are also figured and briefly discussed.
MATERIAL AND METHODS
The types of Bourciera amazonensis sp. nov., B. im- baburensis sp. nov. and the holotype of B. intermedia sp. nov. were acquired through shell trade by the second author (CD) and stored in the collection of the Natural History Museum of Rotterdam in Rotterdam (The Netherlands). The holotype of B. distincta sp. nov. was found in the collection of Naturalis Biodiversity Center in Leiden (The Netherlands) by the first author (MR). The type specimens of B. curvi- digitata sp. nov. and the paratype of B. intermedia sp. nov. were found while studying the collection of The Zoological Museum Hamburg (Germany) and the holotype of B. ovata sp. nov. was already present in the DMNH collection. Observations of Bourciera intermedia sp. nov. in the “Un poco del ChocO" rainforest reserve form part of a more extensive study on all terrestrial gastropods present in this area (Roosen in prep.). Most other records were obtained by accessing museum and iNaturalist records through invertebase.org and literature by both authors. Last, some observations made by the second author (CD) while travelling through Ecuador were also included, even though the specimens could not be collected. Records of unidentified Bourciera specimens and un- verifiable records were excluded.
Measurements were taken to the nearest 0.1 mm using Vernier calipers. Shell height (H) was measured from the apex to the lowest part of the inner lip of the aperture. The shell width (W) was measured at the widest section perpendicular to the coiling axis; Height of the aperture (HA) was measured from the lower to the highest extension of the peristome. All measurements are in mm. Whorls were counted to the nearest % whorl following GITTENBERGER et al. (2004).
Type material of the species described in this paper is deposited in the collections of the Delaware Museum of Natural History, Wilmington, Delaware, U.S.A. (DMNH), Natural History Museum Rotterdam, Rotterdam, the Netherlands (NMR), Naturalis Biodiversity Center, Leiden, The Netherlands (RMNH) and the Zoological Museum Hamburg, Hamburg, Germany (ZMH). Additional specimens analyzed were housed in the following collections: Florida Museum of Natural History, Gainesville, Florida, U.S.A. (UF), Senckenberg Natural History Collections Dresden, Dresden, Germany (SNSD), the Natural History Museum, London, England (NHMUK) and the Museum of Natural History Berlin, Berlin, Germany (ZMB).
Abbreviations: a.s.l. – above sea level, Coll. – Collection, obs. – observation, D – diameter, H – shell height, HA – aperture height, Tl – type locality, W – shell width.
SYSTEMATIC PART
Family: Helicinidae Férussac, 1822
Genus: Bourciera Pfeiffer, 1852
Type species: Bourciera helicinaeformis Pfeiffer, 1852b
Bourciera – PFEIFFER 1852a: 178
Bourcieria Pfeiffer (non Bonaparte, 1850) – SYKES 1907: p. 312 (incorrect subsequent spelling of Bouciera)
Pseudhelicina – SYKES 1907: p. 312 (unnecessary replacement name)
Pseudohelicina – CORREOSO 2008: pp. 59–61 (incorrect subsequent spelling of Pseudhelicina)
Diagnosis. Body bicoloured, yellowish light-grey on the outer edge, dark grey or black in the middle. Eyes are positioned at the base of the stalks, stalks are grey to black in colour. A dark grey line is present between the dark part of the foot and the stalks. Above and below its eyes, its head has the same colour as the outer edge of its body.
Shell small to medium sized, depressed conical-globular, with a large aperture. Periostracum coloured. Nucleus large, protoconch-teleoconch transition unclear. Peristome extended in adult specimens, with projection on the base of the columella. Aperture closed by a corneous, paucispiral operculum.
Remarks. SYKES (1907) proposed Pseudhelicina as a replacement name for Bourciera based on incorrect subsequent spelling of the genus as Bourcieria. This spelling mistake was only found in SYKES (1907) publication. It is true that Bourcieria was already introduced by BONAPARTE (1850) as a genus of birds, but as the spelling of Pfeiffer’s genus differs it should be considered valid as BAKER (1922) proposed. Regardless, Pseudhelicina and other variants of Sykes’ name occasionally show up in literature (e.g. THIELE 1935, CORREOSO 2008).
The paucispiral operculum indicates that Bourciera is one of the most basal genera of Helicinidae according to BAKER (1922). Bourciera was absent from Wagner’s monograph on Helicinidae (WAGNER 1911). All species of which multiple specimens are available show little intraspecific variation, aside from slight differences in dimensions.
Key to the species:
The shape of the aperture is:
a. circular to subcircular . ...................2
b. ovate to ovate-drop shaped ...............5
2. The spire is:
a. elevated, with slightly depressed or flattened whorls ...............................3
b. depressed, with convex whorls ............4
3. The width is:
a. less than 11 mm . Bourciera amazonensis sp. nov.
b. more than 11 mm ... Bourciera distincta sp. nov.
4. The projection on the lower left part of the peristome is:
a. large, angulate, curved forward ............. .............. Bourciera curvidigitata sp. nov.
b. small, rounded .. Bourciera fraseri (Pfeiffer, 1859)
5. The spire is:
a. more than 25% of total height, with slightly depressed whorls ........................6
b. between 18 and 25% of total height ........7
c. less than 18% of total height, with convex spire whorls ...............................8
6. The shell has:
a. a green periostracum, large aperture and medium sized triangular projection ............. Bourciera intermedia sp. nov.
b. a yellow periostracum, medium sized aperture and small, delimited projection ............. ...... Bourciera helicinaeformis Pfeiffer, 1852b
7. The projection on the lower part of the peristome is:
a. present ............... Bourciera ovata sp. nov.
b. absent ......... Bourciera imbaburensis sp. nov.
8. The shell has:
a. a green periostracum and rounded bulge instead of a more typical projection . . . . . . . . . . . ............. Bourciera striatula Miller, 1879
b. a brown periostracum and small, pointed upward projection ......................... ..........Bourciera aff. striatula Miller, 1879
c. a green periostracum and large, triangular projection ...... Bourciera viridissima Miller, 1879
Bourciera amazonensis sp. nov.
urn:lsid:zoobank.org:act:735E0D5E-90F5-4593-A87B-C90D2BF420AE
Type material. Holotype: NMR 9930-00192199 (dry shell) Ecuador, Sucumbios province, Cantón Cuyabeno, Parroquia Tarapoa, Preecoperativa San José; paratype(s): NMR 9930-00192200 (1 dry shell), same data as the holotype; NMR 9930-00192201 (1 dry shell), same data as the holotype; NMR 993000192203 (1 dry shell), same data as the holotype.
Additional material. UF139094 (1 dry shell) Ecuador, Morona-Santiago province, 2 km W of Patuca, 400 m a.s.l.
Type locality. Ecuador, Sucumbios province, Cantón Cuyabeno, Parroquia Tarapoa, Preecoperativa San José.
Description. Small, medium-depressed conical-globular shell with slightly flattened spire whorls. Spire elevated, 35–39% of total height. Sculpture consists of weak axial growth striae. Aperture small, subcircular to drop shaped. Peristome well developed Projection on the posterior edge of the peristome limited to a small bulge. Operculum corneous, pau- cispiral, consisting of two densely coiled volutions. Umbilicus closed by umbilical callus. Periostracum thin, light-brown to orange, with irregular translucent streaks.
Dimensions. H: 7.2–7.5 mm; W: 8.1–8.7 mm; HA: 4.8–5.5 mm; whorls: 4¼–4½.
Cross-Diagnosis. Differs from B. helicinaeformis, B. imbaburensis sp. nov., B. intermedia sp. nov., B. ovata sp. nov., B. striatula and B. viridissima by its near circular aperture, smaller size and dark brown periostracum. Moreover, most of these species were described from the west side of the Andes, clearly separating their populations from those of the new species that occurs on the east side. Bourciera curvidigitata sp. nov. and B. fraseri are most similar, as they also have a relatively small aperture and are of the same size. However, these species have a more depressed, wider shell, have more convex whorls and lack the depression on the side of the aperture. In addition, the projection of B. curvidigita sp. nov. is much larger and more angulate. Bourciera distincta sp. nov. is much larger, has a more angulate projection and lacks the depression on the side of the aperture.
Habitat and ecology. The species was found alive by the second author (CD) in the understory of Terra Firme forest near the Cuyabeno nature reserve (Ecuador, Sucumbios province, Figs 20, 22).
Distribution. Ecuador: Morona-Santiago – 2 km W of Patuca, 400 m a.s.l. (UF139094); Pastaza – Canelos (DMNH164017); Sucumbios – Cantón Cuyabeno, Parroquia Tarapoa, Preecoperativa San José.
Etymology. The specific epithet refers to the Amazon rainforest, the ecoregion its type locality and all other known localities are within it.
Remarks. The current record greatly extends the distribution of Bourciera into the Amazon rainforest.
Bourciera curvidigitata sp. nov.
urn:lsid:zoobank.org:act:CC184AC9-F69B-4A1C-B296-5446035CE1DD
Helicina (Euneritella) cf. rhodostoma – GUEVARA 2008: pp. 95–97 (non Gray, 1824).
Type material. Holotype: ZMH 38322 (dry shell) Peru, San Martin, Rioja, Cueva Santuario de la Amazona, 76 km NW of Moyobamba, 400 m a.s.l., 05°43'31"S, 77°34'33"W, leg. guevara 08.03.2001; paratypes ZMH 10179 (4 dry shells), same data as the holotype.
Type locality. Peru, San Martin, Rioja, Cueva Santuario de la Amazona, 76 km NW of Moyobamba, 400 m a.s.l., 05°43'31"S, 77°34'33"W.
Description. Shell depressed conical-globular, relatively broad. Spire elevated, 22–23% of total height. Whorls convex, sculpture consists of indistinct growth lines. Last whorl relatively large, aperture subcircular. Peristome broadly extended, with a large, acute, elongate triangular, forward curved projection near the base of the shell. Umbilicus closed by umbilical callus. Periostracum yellowish brown.
Dimensions. H: 7.1–8.2 mm; W: 9.5–10.8 mm; HA: 6.2–7.4 mm; whorls: 4¼–4½.
Cross-Diagnosis. The new species seems to be closely allied to B. distincta sp. nov., which is larger, has less convex whorls, a drop shaped aperture and smaller projection. Bourciera fraseri is also similar, but it differs by its smaller size and small, rounded projection. Bourciera amazonensis sp. nov. differs most notably by its higher spire, flattened whorls and small rounded projection. Bourciera ovata sp. nov. is larger, has a smaller projection and has a larger, more ovate aperture. All other species have an ovate or drop shaped aperture, are distinctly larger, generally have less convex whorls and occur only on the western side of the Andes in Ecuador.
Distribution. Peru: San Martin – Rioja, Cueva Santuario de la Amazona.
Etymology. The specific epithet refers to the shape of its projection, which is reminiscent of a curved (curvum) finger (digitus).
Remarks. GUEVARA (2008) identified the type specimens as Helicina (Euneritella) cf. rhodostoma (Gray, 1824), a highly variable, colorful helicinid from Dominica which has very little to do with Bourciera in general. MOGOLLÓN & BREURE (2019) demonstrated that several similar faulty identifications were present in Guevara’s paper.
The new species represents the first accurate locality record for a Bourciera species in Peru. It is possible that the specimens reported from northern Peru by ADAMS (1870) as B. fraseri Pfeiffer, 1859 are mis-identified, but we could not locate his material for further study.
Bourciera distincta sp. nov.
urn:lsid:zoobank.org:act:ADCA66E3-7CBD-4611-A2E6-FCC31D1319C5
Type material. Holotype: RMNH.MOL.152706 (dry shell) Ecuador, without specific locality (leg. SOWERBY & FULTON 1917).
Type locality. Ecuador
Description. Relatively large, depressed conical-globular shell, with slightly flattened spire whorls. Spire elevated, 30% of total height. Faint axial growth striae cover the entire teleoconch, oblique striae visible on the last ¼ whorl. Aperture medium sized, circular in shape. Peristome extended with a small pointed projection in the lower left corner. The umbilicus is closed by umbilical callus. Periostracum orange-brown, intersected by translucent streaks.
Dimensions. Holotype: H: 11.2 mm; W: 14.5 mm; HA: 9.9 mm; whorls: 5¼.
Cross-Diagnosis. The new species is most similar to B. amazonensis sp. nov., B. curvidigitata sp. nov. and B. fraseri as these also have a more or less circular aperture and medium depressed spire. However, B. distincta sp. nov. is much larger than all these taxa and has less convex whorls. Moreover, B. amazonensis sp. nov. and B. fraseri have a smaller, more rounded projection. Bourciera curvidigitata sp. nov. does have an angulate projection, but it is comparatively larger than the projection of B. distincta sp. nov. In size and general shape, it compares best to B. ovata sp. nov. which has a wider shell, more ovate aperture and smaller projection. Bourciera imbaburensis sp. nov., B. intermedia and B. helicinaeformis are overall more slender and have a larger, more ovate aperture. Bourciera striatula and B. viridissima have a more depressed spire, convex whorls and larger, more ovate apertures.
Distribution. Ecuador.
Etymology. The specific epithet refers to the distinctive properties of this species, which make it easy to separate from the other taxa described in this paper.
Remarks. The species is described based on one shell present in the historical collection of Naturalis Biodiversity Center.
Bourciera fraseri (Pfeiffer, 1859)
Cyclostoma (Bourciera) fraseri – PFEIFFER 1859: p. 28, pl. 44, fig. 1.
Bourciera fraseri (Pfeiffer, 1859) – MILLER 1879: p. 146.
Bourciera fraseri (Pfeiffer, 1859) – COUSIN 1887: p. 87.
Bourciera fraseri (Pfeiffer, 1859) – GERMAIN 1907: p. 62 (= Bourciera viridissima Miller, 1879?).
Bourciera fraseri (Pfeiffer, 1859) – CORREOSO 2008: p. 60.
Bourciera fraseri (Pfeiffer, 1859) – BREURE et al. 2022: p. 19, fig. 4.
Studied material. NHMUK 20130063 (syntype, 1 shell, dry), Ecuador, Azuay province, Cuenca; ZMB 50854 (2 shells, dry), Colombia, Narino or Putumayo department, between Pasto and Mocoa, leg. hoPKe.
Redescription. Shell depressed conical-globular, relatively broad, with convex spire whorls. Spire elevated, up to 31% of total height. Sculpture consists of indistinct growth lines. Last whorl of medium size, aperture subcircular. Peristome well developed, with a small rounded projection near the base of the shell. Umbilicus closed by callus. No periostracum preserved.
Dimensions. H: 6.7 mm; W: 9.5 mm; HA: 5.6 mm; whorls 4½.
Cross-Diagnosis. In size and general shape it resembles B. amazonensis sp. nov., but B. fraseri can be distinguished by its lower spire, wider shell and more convex whorls. Bourciera curvidigitata sp. nov. and B. distincta sp. nov. are also similar, but these species become larger and have larger, angulate projections. All other known taxa are much larger than B. fraseri and have a more ovate, larger aperture.
Distribution. Colombia: Narino or Putumayo – between Pasto and Mocoa (ZMB 50854); Ecuador: Azuay – Cuenca (TL); Morona-Santiago – Bomboisa (iNaturalist obs. 86714606); Peru: Eastern slopes of the Andes (ADAMS 1870, RAMÍREZ et al. 2003).
Remarks. Bourciera fraseri is the only Bourciera species known from Colombia, Ecuador and Peru. Based on new observations of a living individual of B. fraseri (iNaturalist obs. 86714606), it is likely that it inhabits the rainforest on the eastern slopes of the Andes. It is possible that records from Peru are misidentified B. curvidigitata sp. nov. or another Amazonian species.
GERMAIN (1907) also reported this species from the west side of the Andes, but also mentioned that he did not see any differences between B. fraseri and B. viridissima. Therefore we suspect his record is more likely a misidentified B. viridissima.
Bourciera helicinaeformis Pfeiffer, 1852
Bourciera helicinaeformis Pfeiffer, 1852 – PFEIFFER 1852a: p. 178 (nomen nudum).
Bourciera helicinaeformis – PFEIFFER 1852b: pp. 312–313.
Cyclostoma heliciniforme – PFEIFFER 1853: pp. 151–152.
Bourciera helicinaeformis Pfeiffer – MILLER 1879: p. 145.
Bourciera helicinaeformis Pfeiffer – COUSIN 1887: pp. 273–274.
Bourciera helicinaeformis Pfeiffer, 1852 – GERMAIN 1907: p. 62.
Pseudhelicina helicinaeformis (Pfeiffer) – SYKES 1907: p. 312.
Bourciera helicinaeformis (Pfeiffer, 1852) – CORREOSO 2008: pp. 59–61, figs 1–4.
Pseudohelicina helicinaeformis (Pfeiffer, 1852) – CORREOSO 2008: pp. 59–61, figs 1–4.
Bourciera heliciniforme Pfeiffer, 1853 – BREURE & ARAUJO 2017: pp. 17–18, fig. 9.
Bourciera helicinaeformis Pfeiffer, 1852 – BREURE et al. 2022: pp. 19–20, fig. 5.
Studied material. NHMUK 20130062 (syntypes, 3 shells, dry), Ecuador, Pichincha province, Yaraqui Valley; NHMUK 1862.4.24.1 (2 shells, dry), Ecuador; NMR 9930-201568 (1 shell, dry), Ecuador, Pichincha province, Tandayapa.
Redescription. Shell somewhat elongate, with an elevated spire that is 25–31% of total height. Whorls convex, slightly flattened from above. Sculpture consists of indistinct growth lines. Last whorl large, aperture ovate drop shaped. Peristome broad, with a small triangular projection near the base of the shell. Umbilicus closed by callus. Operculum paucispiral, densely coiled, corneous (obs. C. DoraDo 2018). Periostracum yellow-brown (e.g. CORREOSO 2008).
Dimensions. H: 12.0 mm; W: 14.9 mm; HA: 10.3 mm; whorls 5¼–5½.
Cross-diagnosis. Bourciera intermedia sp. nov. can be separated from B. helicinaeformis by its green periostracum, larger aperture and larger triangular projection. Another similar species is B. imbaburensis sp. nov., which lacks a projection on the lower left corner of the peristome, has a higher, more ovate aperture and has a distinctly lower spire. Bourciera ovata sp. nov., B. striatula and B. viridissima differ by their lower spire, more convex whorls and larger, more ovate apertures. Bourciera amazonensis sp. nov., B. curvidigitata sp. nov., B. distincta sp. nov. and B. fraseri differ from B. helicinaeformis by their relatively small, circular aperture. Moreover, most of these species, with exception of B. distincta sp. nov., are much smaller than B. helicinaeformis.
Distribution. Ecuador: Cotopaxi – Sigchos, near Latacunga (DMNH 151934); San Francisco de la Pampas, Otonga Nature Reserve (ZMH 124773, ZMH 124774, ZMH 124775); Imbabura – without specific locality (CORREOSO 2008); Manduriacu (iNaturalist obs. 4839118, 4839117, 4839116); Pichincha – Yaraqui Valley (TL); Los Puentes (COUSIN 1887); Nanegal (MARTENS 1885); San Tadeo, chemin de Pachajal (GERMAIN 1907); Tandayapa (NMR 9930-00201568); Mindo (DMNH 151928).
Remarks. The second author (CD) visited Tandayapa in 2021 to photograph living B. helicinaeformis based on the locality data of NMR 9930-00201568. One specimen was found and photographed (Fig. 18). It was covered with lichen, which we have not seen in any other Bourciera specimens or in literature. At the moment the ecological relationship between Bourciera and the lichen is unclear and requires further study.
CORREOSO (2008) also figured living specimens with a reddish periostracum as B. helicinaeformis, but they could be misidentified B. imbaburensis sp. nov. However, based on the pictures provided the specimens cannot be identified with any certainty.
The specimens collected from the Otonga Nature Reserve differ from the typical specimens of B. heli- cinaeformis by reaching 1.5 times the size at equal or less volutions. As there are no other distinguishing characteristics in the shell and the anatomy cannot be studied, we refrain from describing it as a new (sub)species.
Bourciera imbaburensis sp. nov.
urn:lsid:zoobank.org:act:D63A0807-A0F2-4440-A5E4-82658270ACF0
Type material. Holotype: NMR 9930-00198034 (1 shell, dry) Ecuador, Imbabura Province, El Chontal; paratype(s): NMR 9930-00198035 (1 shell, dry), same data as the holotype.
Type locality. Ecuador, Imbabura Province, El Chontal.
Description. Medium sized, slender, elongate shell, with an elevated spire. Spire 22% of total height. Faint axial growth striae cover the entire teleoconch. Spire whorls are convex. Aperture large, oval in shape. Peristome well developed, relatively thin, concave at the posterior side. Umbilicus closed by umbilical callus. Remnants of a reddish-yellowish periostracum are present on both type specimens.
Dimensions. H: 11.8–12.1 mm; W: 14.1–14.6 mm; HA: 10.2–10.4 mm; whorls: 4½–4¾.
Cross-Diagnosis. Differs from most species by its slender shell, convex whorls and peristome without projection. Bourciera striatula Miller, 1879 was drawn without a projection on its peristome, but a small projection is mentioned in the description. In addition, this species is larger and has a relatively low spire, resulting in a less slender appearance.
Distribution. Ecuador: Imbabura – El Chontal.
Etymology. The specific epithet refers to its type locality, which is located in the Imbabura province.
Remarks. CORREOSO (2008) reports specimens of B. helicinaeformis from the type locality of the B. imbabu- rensis sp. nov., but no pictures of these specimens are provided in this publication.
Bourciera intermedia sp. nov.
urn:lsid:zoobank.org:act:83D97C4B-92A4-4148-8168-7DF2CA8D373F
Type material. Holotype: NMR9930-198033 (1 shell, dry), Ecuador, Pichincha province, Nanegal; Paratype: ZMH 143663 (1 shell, dry), Ecuador, Imbabura province, Los Cedros reserve, 1300 m a.s.l.
Type locality. Ecuador, Pichincha province, Nanegal.
Additional material. RMNH.MOL.152707 (1 shell, dry), “Ecuador”; ZMA.MOL.316032 (2 shells, dry) “Ecuador”.
Description. Shell broad, depressed conical-globular. Spire 28% of total height. Whorls convex, slightly flattened from above. Sculpture consists of indistinct growth lines. Last whorl large, aperture ovate drop shaped. Peristome well-developed, with a medium sized triangular projection near the base of the shell. Umbilicus closed by callus. Periostracum dark green to yellow in colour.
Dimensions. H: 11.3–12.9 mm; W: 13.3–17.0 mm; HA: 10.0–12.8 mm; whorls: 4½–5.
Cross-Diagnosis. This form is closely allied to B. helicinaeformis and B. imbaburensis sp. nov., but differs in having a comparatively large projection, higher aperture, wider shell and green periostracum. It is also reminiscent of B. striatula and B. viridissima, but these species typically have more convex spire whorls, a lower spire and more extended peristome. Bourciera ovata sp. nov. also has a wider shell, but differs from B. intermedia sp. nov. in its more ovate aperture, thin peristome with small projection and brown periostracum. All other taxa differ clearly by their more circular, smaller aperture.
Distribution. Ecuador: Imbabura – Los Cedros reserve, 1300 m a.s.l. (ZMH 143663); Pichincha – Nanegal (NMR9930-198033); Un poco del Chocó reserve, near Las Tolas, Gualea, 1200 m a.s.l. (obs. M. T. ROOSEN 2019)
Etymology. The specific epithet refers to its shell characteristics, which seem intermediate to that of B. helicinaeformis and B. viridissima.
Remarks. Bourciera intermedia sp. nov. is very similar to both B. helicinaeformis and B. viridissima sp. nov. It is possible that the new species was confused with these taxa in the past.
Bourciera ovata sp. nov.
urn:lsid:zoobank.org:act:CC12942F-4697-4388-A2F7-36F1487F08CC
Type material. Holotype: DMNH 151926 (1 shell, dry), Ecuador, Pastaza province, Puyo.
Type locality. Ecuador, Pastaza province, Puyo.
Description. Shell depressed conical-globular, relatively wide. Spire 22% of total height, whorls convex. Sculpture consists of indistinct growth lines. Last whorl large, aperture high ovate in shape. Peristome well-developed, with a small, pointed projection below the columella. Umbilicus closed by callus, periostracum light brown.
Dimensions. H: 11.0 mm; W: 13.0 mm; HA: 8.6 mm, whorls 4½ (pers. com. KITTLE 2022).
Cross-Diagnosis. It is most reminiscent of B. im- baburensis sp. nov., which differs by its more elongate shell and the lack of a projection while the peristome is properly developed. Bourciera ovata sp. nov. has a more ovate aperture, wider shell and more convex spire whorls than B. helicinaeformis and B. intermedia sp. nov. Another similar species is B. distincta sp. nov. which also has a wider shell, but differs from B. ova- ta sp. nov. by its less convex whorls, less ovate aperture and translucent streaks on the periostracum. Bourciera striatula and B. viridissima have a more depressed spire, larger aperture, more extended peristome and green periostracum. In addition, B. viri- dissima has a much larger, more triangular projection. Bourciera amazonensis sp. nov., B. curvidigitata sp. nov. and B. fraseri occur in more or less the same area as B. ovata, but they are all smaller and have more circular apertures.
Distribution. Ecuador: Pastaza – Puyo.
Etymology. The specific epithet refers to its ovate aperture, which is one of the key characteristics of the new species.
Remarks. Only one specimen of this type is available at the moment, but as it represents the only larger species with an ovate aperture on the east side of the Andes its description is justified.
Bourciera striatula Miller, 1879
Bourciera striatula – MILLER 1879: p. 145, pl. 5, fig. 6. Bourciera striatula Miller, 1879 – COUSIN 1887: p. 274. Bourciera striatula Miller, 1879 – BREURE 2019: p. 135. Bourciera striatula Miller, 1879 – BREURE et al. 2022: p. 20, fig. 6A.
Diagnosis. See MILLER (1879).
Dimensions. H: 11 mm; D(maximum): 18 mm; D(minimum): 13 mm; whorls: unknown (MILLER 1879).
Cross-Diagnosis. As the characteristics of this species are still unclear, the only specimen known is lost and the drawing does not match its description, it cannot be properly compared to other taxa. Based on Miller’s description, the species is very similar to B. viridissima and differs only by its smaller projection, larger aperture and overall larger size.
Distribution. Ecuador: Pichincha – Pilatón valley (TL).
Remarks. No specimens could be found exhibiting the same characteristics as Miller described and the holotype is lost. Without any type material and with only poor drawings available, we cannot be sure about the identity of B. striatula. Based on Miller’s description, it could be a valid species (MILLER 1879).
Bourciera aff. striatula Miller, 1879
Studied material. Only observations.
Dimensions. H: 16 mm; W: 18 mm; HA: 14 mm, whorls 5 (extrapolated from photograph).
Distribution. Ecuador: Esmeraldas – Canande Reserve (iNaturalist obs. 4871733).
Remarks. It is likely that several observations from the western lowlands of Ecuador belong to this species, but only on one occasion the aperture was photographed which allowed identification as an un-described species, likely allied to Bourciera striatula Miller, 1879. It differs from Miller’s description of B. striatula by its brown periostracal colour and different shaped projection, which is only a small, rounded bulge in B. striatula. The broad shell, low spire, ovate aperture and small, pointed, upward projection seem to distinguish B. aff. striatula from all other species from Western Ecuador. Material should be collected to confirm it is a different species and describe it as such.
Bourciera viridissima Miller, 1879
Bourciera viridissima – MILLER 1879: p. 146, pl. 5, fig. 5. Bourciera viridissima Miller, 1879 – COUSIN 1887: p. 274. Bourciera viridissima Miller, 1879 – BREURE 2019: p. 135.
Bourciera viridissima Miller, 1879 – BREURE et al. 2022: p. 20, fig. 6B.
Studied material. NHMUK 20130111 (1 shell, dry) “Brazil”; SNSD MTD 55927 (1 shell, dry) Ecuador, Santo Domingo de Los Tsáchilas, Santo Domingo.
Redescription. Shell depressed with convex whorls and bright green periostracum. Spire 14–18% of total height. Sculpture consists of indistinct growth lines. Aperture large, subcircular to ovate with broad peristome and large triangular projection near the base of the shell. Upper part of the peristome can extend above the apex. Umbilicus closed by umbilical callus.
Dimensions. H: 12.6 mm; W: 16.7 mm; HA: 13.7 mm, whorls 4½.
Cross-Diagnosis. Although distribution of B. virid- issima overlaps with that of B. helicinaeformis and B. intermedia sp. nov., it can be distinguished by its more depressed spire, more convex spire whorls, rounder aperture, broader peristome and larger projection in adult specimens. In addition, so far there are no specimens of B. helicinaeformis known with a green periostracum. It differs from B. imbaburensis sp. nov. in having a projection on the peristome, having a lower spire and less convex spire whorls. Bourciera striatula and B. aff. striatula are larger and have a smaller projection that differs in shape from that of B. viridissima. Moreover, B. aff. striatula has a brown periostracum. Bourciera ovata sp. nov. has a smaller, more ovate aperture, smaller projection and light brown periostracum in comparison to B. viridissima. All other known species have a smaller, circular to drop-shaped aperture, smaller projection and are generally smaller than B. viridissima.
GERMAIN (1907) saw no differences between B. viridissima and B. fraseri, but the latter is smaller, occurs on the east side of the Andes, has a more elevated spire and a smaller, more circular aperture than B. viridissima.
Distribution. Ecuador: Esmeraldas – near La Concordia (pers. com. Breure 2022); Imbabura – Cotacachi (iNaturalist obs. 41301754; 36380240); Pichincha – Pilatón valley (TL); San Nicolas (COUSIN 1887); Santo Domingo De Los Tsáchilas – Santo Domingo (SNSD MTD 55927).
Remarks. The specimen from Santo Domingo (SNSD MTD 55927) is part of the collection of Reibisch. Both Reibisch and Miller received their Ecuadorian material from Wolf and it is likely they all knew each other (MILLER 1878, 1879, REIBISCH 1896). Based on this we suspect that SNSD MTD 55927 represents true Bourciera viridissima as Miller intended the species, even though its locality data differs from the type locality of B. viridissima. The large projection typical for this species is broken off.
NHMUK 20130111 shows the same characteristics as the specimens from Santo Domingo and La Concordia. It is likely that its locality data (Brazil) is a proxy for an unknown locality in South-America and the shell could be from Ecuador as well, although there is a small possibility that a similar species occurs somewhere in Brazil.
DISCUSSION
The occurrence of Bourciera amazonensis sp. nov., B. curvidigitata sp. nov., B. fraseri and Bourciera ova- ta sp. nov. in the Amazon rainforest proves that the genus has a much wider distribution then previously assumed (CORREOSO 2008). Based on these records, it is possible that the genus occurs in a larger part of the Amazonian basin, although it was not recorded in the study in the Peruvian Amazon by WENDEBOURG & HAUSDORF (2019). Additional surveys in the Amazon rainforest of Brazil, Colombia, Ecuador, Peru and other countries should be conducted to corroborate this.
As demonstrated, there are also indications of additional new species of Bourciera in Ecuador and it is likely there will be more. Most of Ecuador remains under sampled for smaller terrestrial gastropods and it seems that each species of Bourciera has a relatively limited distribution, with exception of B. amazon- ensis sp. nov., B. fraseri and B. helicinaeformis (Pfeiffer, 1852b). It is expected that further studies will reveal more new Bourciera species.
New records of B. viridissima Miller, 1879 support it is a valid species. This together with the newly published pictures of the NHMUK and SNSD specimens should help other malacologists to correctly identify Bourciera viridissima during succeeding studies. Hopefully B. striatula Miller, 1879 will also be rediscovered after this publication, if only to assess its validity. Thus, including the six newly described species, 10 species level taxa of Bourciera are reported in this paper. The distribution of the genus is greatly extended to the lowlands of West-Ecuador and the Amazon rainforest of Colombia, Ecuador and Peru. Its range likely extends further into the Amazon rain-forest. Further research should teach us more about their ecology, distribution and will probably yield additional species of Bourciera.