INTRODUCTION
Mexico is among the most zoologically diverse nations of the world (third in amphibians and reptiles) (Conabio 2023). High endemism and genetic diversity, the range of climates and the complexity of its geological history contribute to making it one of the 17 most megadiverse countries (Espinosa Organista et al. 2008), a product, also, of its position on the boundary of the Nearctic and Neotropical regions (Rzedowski 1978). Within Mexico, Chiapas is among the most diverse states, holding 11.7% of Mexico’s reptiles, 8.8% of amphibians, and 800 species of diurnal butterflies which represent 40% of all butterfly species in the country (De la Maza & Carabias 2011). The state’s varied physiography contributes to this, giving rise to great local variation in climate and ecosystems (González-Espinosa et al. 2004).
To date, 22 families and 158 species and subspecies of terrestrial and freshwater molluscs are known from Chiapas, representing about 9.3% of the national fauna (Naranjo-García & Fahy 2010, Naranjo-García & Smith 2014, Tovar-Juárez et al. 2020). Thompson (2011), however, states that roughly 35% of the freshwater and terrestrial molluscs in Mexico and Central America are known, and as Avendaño-Gil et al. (2013) suggest, there is much more to be discovered in Chiapas. This paper reports on unpublished records from the state held in the National Collection of Molluscs of the Institute of Biology of the National Autonomous University of Mexico (UNAM).
MATERIALS AND METHOD
Most of the specimens were collected from a site 7.3 km north of Ciudad Cuautemoc, deposited at the National Collection of Mollusks of the Institute of Biology of the National Autonomous University of Mexico (UNAM), while the remaining specimens come from other sites, collected by the lead author (Fig. 1). The features describing the sites are shown in Table 1.
The collecting sites showed different degrees of human intrusion; at Custepec and La Perla undergrowth vegetation was removed for shade coffee cultivation, and at Las Champas below the tree canopy the undergrowth showed signs of human intervention. The site at Ciudad Cuauhtémoc was a ravine in 1988, but in 2023 the habitat had been destroyed by the widening and construction of a more modern road to enable cattle farming. El Silencio possesses an old railway, and the body of water has been invaded by an introduced grass. At Lagos de Colon we observed hydrobioids (“with narrow environmental tolerance” Czaja et al. 2020). It is an attraction for swimmers; further development could threaten these species.
Specimens were collected manually, taken directly from below rocks, trees and river banks, and under fallen logs or weeds. Also, about 100 gr of humus at each site was taken, which was placed in zip lock plastic bags. The conchological material was placed into flasks and labelled. The living material was relaxed and later placed into bottles with 35% alcohol solution, in which specimens remained for 24 hours. After that time, they were transferred into 70% alcohol. In the laboratory, humus was sieved though a series of sieves (3 mm, 0.96 mm and 0.5 mm) from where the shells were sorted. The genera key for Mexican terrestrial molluscs (Fahy 2003) was used for the initial taxonomic identification. Selected taxonomic articles were then used to achieve specific identification, and a number of specimens were compared to material from the National Mollusc Collection (Colección Nacional de Moluscos, Instituto de Biología, Universidad Nacional Autónoma de México). Here we follow the classification given by Bouchet et al. (2017) and accepted names from the platform MolluscaBase.
Institutional abbreviation: CNMO – Colección Nacional de Moluscos, Instituto de Biología, Universidad Nacional Autónoma de México.
RESULTS
Of the material studied, 337 specimens are native to Mexico, pertaining to 30 genera and 17 families (Tables 2, 3 & 4).
Table 2
Native species of freshwater snails from southern Chiapas. Symbols used: ES – El Silencio (Suchiate), LC – Lagos de Colón, T – total number of specimens
Table 3
Native species of land snails from southern Chiapas with locality and total number of specimens. Symbols used: CdC – Ciudad Cuauhtémoc (Frontera Comalapa), Cus – Custepec (La Concordía), LC – Lagos de Colón, LCH – Las Champas, LP – La Perla (Maravilla Tenejapa), PC – Puente Colorado (Cacahoatán), T – total number, Nr – new record, Chis – Chiapas, Mex/Chis – Mexico and Chiapas
Table 4
Introduced species of land and freshwater snails in southern Chiapas. Symbols used: CdC – Ciudad Cuauhtémoc (Frontera Comalapa), PC – Puente Colorado (Cacahoatán), T – total number of specimens
The most abundant species were Microceramus concisus concisus (13.5% of the total), Pyrgodomus microdinus microdinus (12.7%), Glyphyalinia indentata paucilirata (9.2%), Paralaoma coloba (6.9%) and Helicina ghiesbreghti (6.6%). Together they comprise 49.0% of total species abundance (Fig. 2).
The abundance per site was highest in Ciudad Cuauhtémoc with 74.9% of the total number of species, which is attributed to the presence of 260 specimens, the smallest number of species was obtained at El Silencio, with less 1% of the total number of species (Fig. 3). Richness per site was highest in Ciudad Cuauhtémoc with 33 species (61.1% of the total) and lowest at El Silencio with only one species (1.9%) (Fig. 4). Ten specimens of four introduced species (in two families) were also found (Table 4). An account of type locality, distribution and remarks is provided for each species.
Fig. 3
Abundance of species per site. Symbols used: CdC – Ciudad Cuauhtémoc, Cus – Custepec (La Concordía), ES – El Silencio (Suchiate), LC – Lagos de Colón, LCH – Las Champas (Frontera Comalapa), LP – La Perla, PC – Puente Colorado (Cacahoatán)
Fig. 4
Diversity of species per site. Symbols used: CdC – Ciudad Cuauhtémoc, Cus – Custepec (La Concordía), ES – El Silencio (Suchiate), LC – Lagos de Colón, LCH – Las Champas (Frontera Comalapa), LP – La Perla, PC – Puente Colorado (Cacahoatán)
FRESHWATER SNAILS
Family Physidae Fitzinger, 1833
Genus Mayabina Taylor, 2003
Mayabina tapanensis (Crosse et Fischer, 1882)
Type locality. Mexico, Oaxaca, near San Pedro Tapanatepec (Thompson 2011).
Distribution. Known from Oaxaca, Mexico to southern Guatemala (Thompson 2011).
Remarks. The species possesses an attractive, bright brown shell. This is the only native freshwater species that has been recorded in the area of Tapachula until now.
TERRESTRIAL SNAILS
Family Helicinidae Ferussac, 1822
Genus Helicina Lamarck, 1799
Helicina cordillerae Pfeiffer, 1857
New record for the state
Type locality. Mexico, Veracruz, Volcán de Orizaba, Rancheria de Jacale (Thompson 2011).
Distribution. Veracruz (Thompson 2011), Chiapas (this paper): Las Champas.
Remarks. Our two specimens resemble closely the species H. cordillerae in general shape, although they are smaller, which makes our identification provisional. Martens (1890–1901) gave the following measurements for it: height 12.5, 11.5 mm, width 10, 9 mm; its height/width ratio being 0.8; our specimens are height 5.9, 6.4 mm; width 8.6, 7.5 mm, height/width ratio: 0.7, and 0.8. The shell is globose sub-depressed with one spiral reddish-brown band above the suture, whorls 5, lip reflected, one specimen is juvenile, without reflected lip. Our specimens differ from H. cordillerae in not showing three spiral bands and their sizes are smaller, as indicated above.
Helicina cordillerae was known only from the state of Veracruz (Thompson 2011); this record will increase the known distribution of the species, assuming that this provisional identification is correct.
Helicina ghiesbreghti Pfeiffer, 1856
Type locality. Mexico, Chiapas (Martens 1890–1901).
Distribution. Mexico, Central, western and northern Chiapas (Naranjo-García & Smith 2014); Tabasco and Guatemala (Thompson 2011). Chiapas (this paper): Puente Colorado, Custepec and La Perla.
Remarks. Helicina ghiesbreghti is widely distributed in Chiapas. It possesses a helicoid depressed shell, with a keel in the body whorl and a protruding folded peristome. It can be found above ground in damp places.
Helicina delicatula Shuttleworth, 1852
Type locality. Mexico, Veracruz, Córdoba, Atoyac (Thompson 2011).
Distribution. Veracruz, Córdoba, Atoyac (Thompson 2011). Chiapas (this paper): Las Champas.
Remarks. Height 7.1 mm, width 8.5, whorls 5 1/4, height/width: 0.8, with a wide reddish-brown band above the shoulder, it is a juvenile without the reflected lip. Measurements of the species in Martens (1890–1901) are height: 6.5 and 9 mm, width 8 and 11 mm, height/width ratio = 0.8. It was previously known from Veracruz and this record will increase its known distribution.
Helicina tenuis Pfeiffer, 1849
Type locality. Panama, San Yago, Prov. Veraguas (Richling 2004).
Distribution. Along the Pacific versant, it is found from Guerrero, Mexico to Panama; along the Gulf of Mexico versant in Veracruz, Mexico, then in Guatemala and various other Central American countries through to Colombia (Thompson 2011). Chiapas (this paper): Puente Colorado.
Remarks. The species is widely distributed in Mexico. The shell has a tall spire and a denticle in the basal outer lip (Richling 2004).
Genus Pyrgodomus Crosse et Fischer, 1893
Pyrgodomus microdinus microdinus (Morelet, 1851)
Type locality. Guatemala, Vera Paz (Thompson 2011).
Distribution. Widely distributed from Tamaulipas and Guerrero, Mexico to Punta Arenas, Costa Rica (Thompson 2011). Chiapas (this paper): Ciudad Cuauhtémoc.
Remarks. This is a small, handsome species that reaches a height of 4 mm. The shell is conical with strong sutures and bulging whorls. Specimens fit well the description and size that the species reaches according with Richling (2004). It can be found in calcium rich soils (Thompson 2011).
Family Neocyclotidae Kobelt et Möllendorff, 1897
Genus Neocyclotus Fischer et Crosse, 1886
Neocyclotus dysoni ambiguus (Martens, 1890)
Type locality. Mexico, Soledad, between Córdoba and Orizaba Veracruz (Martens 1890–1901).
Distribution. Mexico: Chiapas, Oaxaca, Tabasco, Veracruz (Thompson 2011). Chiapas (this paper): Puente Colorado, Custepec.
Remarks. This species has a brown helicoid shell, with an olivaceous hue and a round peristome (Bartsch & Morrison 1942). It can be found above ground and in beds of leaf litter; this group of snails possesses a bright orange body and red tentacles.
Family Ferussaciidae Bourguignat, 1883
Genus Karolus de Folin, 1870
Karolus consobrinus primus De Folin, 1870
Type locality. Karolus primus: Mexico, Veracruz (Thompson 2011).
Distribution. From northeast Mexico to Nicaragua (Thompson 2011). Chiapas (this paper): Ciudad Cuauhtémoc.
Remarks. Most of our specimens are juvenile, two adults are slightly smaller (1.9 mm) than the measurement (2.0 mm) given by Pilsbry (1909–1910).
Family Achatinidae Swainson, 1840
Genus Beckianum H. B. Baker, 1961
Beckianum beckianum beckianum (Pfeiffer, 1846)
Type locality. Polynesia, Opara (Salvador et al. 2018), Pilsbry (1906) pointed out that B. beckianum was not found in Polynesia and that the species resembles more the specimens from Polvón, Nicaragua.
Distribution. Mexico to Brazil (Thompson 2011, Santos Silva et al. 2021). Recorded in Jamaica (Rosenberg & Muratov 2006), in greenhouses in Europe (Horsák et al. 2020) and in Hawaii (Cowie 2000). Chiapas (this paper): Custepec.
Remarks. The whorls are shorter than in Allopeas gracile, with uneven sculpture. Our sample shows the typical shape and sculpture of the description of the species. It is found in tropical rain forest (Goodnight & Goodnight 1956) in southeastern Chiapas (Tovar-Juárez et al. 2020).
Genus Lamellaxis Strebel et Pfeffer, 1882
Lamellaxis martensi martensi (Pfeiffer, 1857)
Type locality. Mexico Veracruz, Córdoba (Thompson 2011).
Distribution. It is found in Mexico (Veracruz, Quintana Roo, Yucatán and Nayarit) and Guatemala (Thompson 2011). Chiapas (this paper): Ciudad Cuauhtémoc.
Remarks. The shell is conical and tall, reaching a height of ca. 10 mm, and is characterised by a short lamella in the middle of the columella.
Lamellaxis mexicanus mexicanus (Pfeiffer, 1866)
Type locality. Mexico, Veracruz, Mirador (Thompson 2011).
Distribution. Eastern Mexico in Tamaulipas to Honduras and Nicaragua (Thompson 2011, Tovar-Juárez et al. 2020). Chiapas (this paper): Ciudad Cuauhtémoc.
Remarks. The adult and one juvenile shells were found 7.3 km north of Ciudad Cuauhtémoc. The adult shell closely resembles the types of Lamellaxis mexicanus mexicanus in measurements and shape. It measures in height 7.8 mm, width 3.4 mm, height/width ratio = 2.29 and has 6 whorls, while Lamellaxis m. mexicanus measures in height 7–9 mm, width 3–4 mm; height/width ratio 2.33, 2.5, with 6 1/2 and 7 whorls (von Martens 1890–1901, Pilsbry 1906). The young specimen has 4 whorls, height 3.7 mm, width 1.9 mm. Whorls rounded, suture well marked, first whorl with very fine growth threads. Columella with a small swollen protuberance at the first third basal section. Sculpture of marked fine growth lines, aperture small. This young specimen is either Lamellaxis mexicanus mexicanus or another subspecies of Lamellaxis mexicanus. More specimens are needed to identify this specimen with certainty since this one shows a finer sculpture than the adult specimen.
Lamellaxis cf. strebelianus (Pilsbry, 1907)
New record for the state and Mexico
Type locality. Nicaragua, Polvón, Dept. León (Pilsbry 1907–1908).
Distribution. Known only from the type locality (Thompson 2011). Chiapas (this paper): Ciudad Cuauhtémoc.
Remarks. Whorls rounded, suture well marked, first whorl with very fine growth threads, the riblets become thicker. Columella with a small swollen edge at the first basal third section. Sculpture of marked fine riblets, separated from each other by about twice the width of the riblet, in between riblets are fine growth lines. Aperture small.
Genus Leptinaria Beck, 1837
Leptinaria sp. 1
Distribution. Collected at 7.3 km north of Ciudad Cuauhtémoc, Chiapas, Mexico.
Remarks. A young specimen with 2 1/3 whorls shell, the first two whorls smooth, then sculptured with growth lines between spaced riblets. The columella covers the tiny umbilicus and possess an acute basal fold or lamella. Height of shell 1.3 mm and width 1.2 mm. Aperture trapezoidal.
Leptinaria sp. 2
Distribution. Collected approximately 4 km from the town of Custepec, Chiapas, Mexico.
Remarks. This species of Leptinaria has a tall conical shell and reaches 8 mm in height. It very much resembles Leptinaria convoluta Martens, 1898; nonetheless, it is slightly larger than L. convoluta and does not bear the parietal lamella that the other does, both L. convoluta and our specimen bear the truncate columella and a fold just above it.
Genus Leptopeas H. B. Baker, 1927
Leptopeas cf. colimense (Crosse et Fischer, 1869)
New record for the state
Type locality. Mexico, Colima (Crosse & Fischer 1869).
Distribution. Colima and Veracruz, Mexico (Pilsbry 1906) and Panama (Pilsbry 1930). Chiapas (this paper): Ciudad Cuauhtémoc.
Remarks. Our specimens more closely resemble L. colimense in general shape and size. L. colimense measurements are in height 15.5 mm and width 3.25 mm, our largest specimen is in height 13.0 mm, width 3.0 mm, other three specimens range from to 5.1–8.8 mm in height and 2.1–2.5 in width. Two more specimens are fragmented. Our largest specimen shows a slightly larger aperture relative to the size of the body whorl than the specimen shown in the Manual of Conchology vol. 18 (Pilsbry 1906: table 29, figs 92, 94). It has been recorded from Colima and Veracruz, Mexico (Pilsbry 1906) and Panama (Pilsbry 1930).
Leptopeas micra (Orbigny, 1835)
Type locality. Bolivia, in the foothills on the eastern extreme of the Andes close to Santa Cruz de la Sierra (Pilsbry 1906).
Distribution. This species has a very ample distribution in Mexico, Central America and the West Indies (Pilsbry 1906, Thompson 2011). Chiapas (this paper): Puente Colorado.
Remarks. Two specimens which measure 6.6 and 7.9 mm in height and 2.3 mm and 2.5 mm in width, whorls 5 and 6 respectively. This species possesses a tall shell with round whorls, and strongly marked suture. Specimens show a sculpture of marked stria that became obsolete in the body whorl. Our specimens have measurements similar to those given by Pilsbry (1946) which are: height 7 mm, width 2.3 mm.
Leptopeas yucatanense (Pilsbry, 1906)
New record for the state
Type locality. Yucatan, Ticul (Pilsbry 1906).
Distribution. Yucatan (Bequaert & Clench 1938), Belize. Orange Walk District (Dourson et al. 2018). Chiapas (this paper): Ciudad Cuauhtémoc.
Remarks. Height 7.1 mm, width 2.3 mm, whorls 6. Our specimen is very close to Leptopeas yucatanense as described by Dourson et al. (2018). The first whorl is smooth with very fine growth lines here and there, half second whorl with faint low riblets, then riblets are well marked over the rest of shell. Suture very well marked, whorls slightly laterally flat, shoulder of third to fifth whorls well marked on right side of shell, aperture trapezoidal, 1.1 mm in length.
Leptopeas sp. 1
Distribution. Known so far from the Municipality of Cacahoatán, Puente Colorado, Chiapas, Mexico.
Remarks. This delicate, tall shell bears a weak spiral lamella located at the end of the columella. One specimen is adult, the tallest has 9 whorls, the others fluctuate between 7 and 8 whorls, height 8.1 to 12 mm, width 2.5 to 3 mm. The species has a tall slender shell; the first whorl is smooth then few growth lines are noticed, subsequent whorls with growth lines that eventually thicken but do not became ribs, the suture is well marked, the body whorl slightly flat on the periphery, the aperture trapezoidal also slender (taller than wide), the small umbilicus covered with the bend columella. At the age of seven whorls the species can reproduce, four shells bear two to three eggs inside the body whorl.
Leptopeas sp. 2
Distribution. It is known from 7.3 km north of Ciudad Cuauhtémoc, Chiapas, Mexico.
Remarks. Leptopeas sp. 2: the six specimens of this lot are of young age, and the shell is more robust that those of Leptopeas sp. 1. The growth lines are stronger, almost as riblets, the aperture trapezoidal but wider. The largest specimen measures in height 4.1 mm, width 2.1 mm and possess 4 1/6 whorls. The first two whorls smooth, then it has fine riblets that stop in the middle of the whorl in subsequent whorls. Suture well marked, columella nearly straight and partly covering the tiny umbilicus. The five other shells are approximately 2 whorls of age. All specimens are too young to be placed into a known species.
Family Punctidae Morse, 1864
Genus Paralaoma Iredale, 1913
Paralaoma coloba (Pilsbry, 1893)
New record for the state and Mexico
Type locality. Nicaragua, Department of Chinandega, Polvón (Pilsbry 1893, Thompson 2011).
Distribution. Laguna de Apoyo (López et al. 2015) and Nicaragua (Pilsbry 1893). Chiapas (this paper): Ciudad Cuauhtémoc.
Remarks. Shell measures: height 1.16 mm, width 1.90 mm, umbilicus 0.23 mm, whorls 4. The embryonic shell has fine spiral parallel lines. Teleoconch with fine riblets over growth lines, three spaced rows of bristles on the periphery, one above the shoulder, another at the middle of body whorl, and the third one around the umbilicus, bristles also widely spaced. Specimens fit the features seen in the SEM photograph of P. coloba at the Academy of Natural Sciences of Philadelphia site. Specimens fragile, 9 of 19 incomplete, five of them broken.
Family Urocoptidae Pilsbry, 1898
Genus Microceramus Pilsbry et Vanatta, 1898
Microceramus concisus concisus (Morelet, 1849)
Type locality. Yucatán, Mexico (Morelet 1849).
Distribution. Mexico (Yucatán and Campeche), Guatemala, Belize, Honduras, and Nicaragua (Thompson 2011); Chiapas (Bequaert 1957, Avendaño et al. 2013). Chiapas (this paper): Ciudad Cuauhtémoc.
Remarks. This species was previously known in the northern and southern Lacandon rainforest (Bequaert 1957, Avendaño et al. 2013). The record near Ciudad Cuauhtémoc is the southernmost site of the species known in the state of Chiapas.
Family Bulimulidae Tryon, 1867
Genus Bulimulus Leach, 1814
Bulimulus cf. coriaceus (Pfeiffer, 1857)
New record for the state
Type locality. Mexico, state of Veracruz (Thompson 2011).
Distribution. Oaxaca, Tabasco and Veracruz (Thompson 2011). Chiapas (this paper): Las Champas.
Remarks. A young specimen, of 4 whorls, height 6.2 mm, width 4.2 mm. Sutures slightly impressed, whorls leaning to globose. This specimen, compared with Bulimulus coriaceus from Atoyac, Veracruz, shows the same general features, being a young specimen that does not show all the features of the adult, which makes us to a certain degree unsure of the identification.
Family Orthalicidae Albers, 1860
Genus Mesembrinus Albers, 1850
Mesembrinus discrepans (Sowerby I, 1833)
New record for the state and Mexico
Type locality. El Salvador, Conchagua (Sowerby 1833).
Distribution. Costa Rica, Nicaragua, El Salvador, Guatemala (Thompson 2011). Chiapas (this paper): Ciudad Cuauhtémoc.
Remarks. Our specimens are a bit smaller (height 4.8–14.4 mm and width 3.8–7.1 mm) than the measurements (height 17–18 mm, width 7.5–8 mm) given by Pilsbry (1899) or Martens (1890–1901) (height 16 mm, width 8 mm). Mesembrinus discrepans and the specimens from near Ciudad Cuauhtémoc show brown slanting streaks that could be few or numerous, as Pilsbry (1899) describes. Mesembrinus from near Ciudad Cuauhtémoc has the brown band close to the umbilicus plus and additional band at the level of the posterior extreme of the aperture just below the suture, this agrees with the description of the species in Martens (1890–1901).
Mesembrinus shattucki (Bequaert et Clench, 1931)
New record for the state
Type locality. Mexico, Yucatán, Chichen Itza (Bequaert & Clench 1931, Thompson 2011).
Distribution. Mexico: Yucatán, Quintana Roo and Guatemala (Thompson 2011). Chiapas (this paper): Ciudad Cuauhtémoc.
Remarks. The tip of the apex is not pinkish brown as in the original description of Mesembrinus shattucki. In our specimens the lower two bands are complete as in M. shattucki, however, instead of having two more bands our specimens bear three bands, the one below the suture is a fading band and, the subsequent two bands below are broken (as brown spots) and slightly narrower if compared with the upper bands of M. shattucki. We consider that the absence of pinkish brown colour of the apex and one more band in our specimens is not enough to regard these specimens as another species. Rather, this might be intraspecies variation.
Genus Drymaeus Albers, 1850
Drymaeus sp. 1
Distribution. Throughout tropical and subtropical America from Argentina north to México, and throughout the West Indies to Florida (Thompson 2011). Chiapas (this paper): Ciudad Cuauhtémoc.
Remarks. The young specimen measures height 0.9 mm, width 0.9 mm. The specimen is almost one whorl that expands rapidly, the sculpture is typical of the Drymaeus apex, spiral puncta. The suture is deep, aperture wide, columella white and straight.
Drymaeus sp. 2
Distribution. Chiapas (this paper): Ciudad Cuauhtémoc.
Remarks. Height 3.0 mm, width 2.4 mm, whorls 2 3/4. Apex light brown with the typical sculpture of the genus present in the two first whorls, then the sculpture becomes moderately strong wrinkles, and over the wrinkles fine cancellated sculpture appears that continues over the body whorl to the edge of the shell. After the second whorl four light brown bands are visible over the body whorl. The first band is near and below the suture, two bands are located in the middle of the body whorl and the fourth band is found below the shoulder. Shoulder with angular periphery.
Family Valloniidae Morse, 1864
Genus Pupisoma Stoliczka, 1873
Pupisoma dioscoricola (C. B. Adams, 1845)
New record for the state
Type locality. Jamaica (Adams 1845).
Distribution. The species is found from south of the United States, Central America, the Caribbean, the Galapagos Islands to South America (Brazil and Argentina) (Hausdorf 2007). Hausdorf (2007) pointed out that it is probably from the tropical old world (Africa, eastern Asia), since other species in the subgenus Ptychopatula thrive there. From the data given in Hausdorf (2007) we could imply that the natural distribution of Pupisoma dioscoricola is Holoarctic, and the same time we humans have contributed with its spread around the world. Chiapas (this paper): Ciudad Cuauhtémoc.
Remarks. Hausdorf (2007) noticed that it is possible to find specimens of P. dioscoricola with short riblets or devoid of them and sometimes both morphotypes in the same population. Our four specimens have small granules at the apex, then spaced riblets on the following whorls. In between the short riblets there is fine cancellated sculpture. One of the specimens is perhaps fully grown, while the other three are not.
Pupisoma mediamericanum Pilsbry, 1920
Type locality. Mexico, Veracruz-Llave: 150 m above Orizaba (Hausdorf 2007).
Distribution. Mexico to Colombia, recorded in Chiapas at Comalapa, Sumidero, Comitán, Ocosingo, La Trinitaria (Hausdorf 2007). Chiapas (this paper): Ciudad Cuauhtémoc.
Remarks. The specimen measures: height 1.8 mm, width 1.4 mm, height/width ratio 1.8/1.4 = 1.2, whorls 4. It shows at the apex small granules, the rest of the shell with spaced shallow riblets and small granules in the middle of them.
Family Vertiginidae Stimpson, 1851
Genus Bothriopupa Pilsbry, 1898
Bothriopupa breviconus Pilsbry, 1917
New record for the state and for Mexico
Type locality. Guatemala, Mountains west of Livingston, Department of Izabal (Thompson 2011).
Distribution. Guatemala, near Cavech Village (Hinkley 1920, Thompson 2011). Chiapas (this paper): Ciudad Cuauhtémoc.
Remarks. This minute snail has a globose ovate-conic shell with scattered pits.
Genus Gastrocopta Wollaston, 1878
Gastrocopta pellucida hordeacella (Pilsbry, 1890)
New record for the state
Type locality. United States, Texas, New Braunfels as Pupa hordeacella (Thompson 2011).
Distribution. West Indies, Mexico, and Guatemala (Bequaert & Miller 1973, Thompson 2011). Chiapas (this paper): Ciudad Cuauhtémoc.
Remarks. All specimens from both dates present the regular number of teeth of the subspecies; four specimens, however, show the three basal teeth enlarged compared with the other nine specimens.
Genus Vertigo Müller, 1774
Vertigo cf. ovata Say, 1822
New record for the state
Type locality. United States, Philadelphia, Pennsylvania (Thompson 2011).
Distribution. Mexico: Baja California Norte, Sonora, Veracruz, San Luis Potosí, West Indies (Thompson 2011). Chiapas (this paper): Ciudad Cuauhtémoc.
Remarks. Two adult and one young specimen. On the adults the basal teeth are supported by a basal lamella; thickness of basal lamella increases towards the middle. Shell of specimens is conical and the aperture possesses 6 teeth. Our adult specimens (1, 2) present a minute infraparietal tooth. The young specimen lacks teeth. The species is close to Vertigo ovata, however V. ovata is more obese than our specimens that present whorls less capacious, V. ovata also does not bear the basal lamella that supports the basal teeth.
Family Gastrodontidae Tryon, 1866
Genus Glyphyalinia von Martens, 1892
Glyphyalinia indentata paucilirata (Morelet, 1851)
New record for the state
Type locality. Guatemala, Salama, Department Baja Vera Paz (as Helix paucilirata Morelet, 1851) and United States, Texas, Lee County (as Zonites indentatus umbilicatus Cockerell, 1893) (Thompson 2011).
Distribution. Midwest and central United States to Guatemala, also in Mexico from Baja California Sur, Durango, Jalisco, Michoacán, Puebla, State of Mexico and Morelos (Thompson 2011). Chiapas (this paper): Ciudad Cuauhtémoc. This is the first record of the species in Chiapas.
Remarks. The shells of these specimens have spaced indented radiating lines and a small umbilicus as in the species description.
Genus Striatura Morse, 1864
Striatura meridionalis (Pilsbry et Ferriss, 1906)
Type locality. United States, Texas, along the Guadalupe River, above New Braunfels (Thompson 2011).
Distribution. United States (New York, Michigan, Arizona, New Mexico, Texas), Mexico (Chihuahua, Sonora, Nuevo León, Puebla, Veracruz, Chiapas) and Nicaragua (Thompson 2011, Van Devender et al. 2012, Pearce & Drescher 2017, Tovar-Juárez et al. 2020). Chiapas (this paper): Las Champas.
Remarks. The fragment measures height: 0.6 mm, width: 1.1 mm. The shell is a translucent, embryonic shell, with fine parallel spiral lines with fine granules on top of them, the rest of shell with fine growth slanting lines and on the top fine granules reminiscent of filigree.
Family Pristilomatidae Cockerell, 1891
Genus Hawaiia Gude, 1911
Hawaiia minuscula minuscula (Binney, 1841)
Type locality. United States, Ohio (Binney 1840).
Distribution. This species is broadly distributed in North America (Alaska and Maine southward to Costa Rica), the Antilles, Japan, Hawaii, Pitcairn, Tahiti, England (in greenhouses), and Ireland (Pilsbry 1946). In Mexico it has been found in Baja California, Sonora, Chihuahua, Nuevo León, San Luis Potosí, Tamaulipas, Veracruz, Campeche, Yucatán, and Chiapas (Thompson 2011). It has been recorded in Palenque (Martens 1890–1901), southern Lacandon rainforest (Naranjo-García 2011), and Ocozocoautla, Chiapas (Naranjo-García & Smith 2014). Chiapas (this paper): Ciudad Cuauhtémoc.
Remarks. The two specimens are juvenile; their morphological features closely resemble those of the species description.
Family Euconulidae H. B. Baker, 1928
Genus Guppya Mörch, 1867
Guppya biolleyi von Martens, 1892
New record for the state
Type locality. Costa Rica, Hacienda Helvetia, in the Costa Cuca (Martens 1890–1901).
Distribution. Costa Rica, Nicaragua, Guatemala and Mexico (Thompson 2011). Chiapas (this paper): Ciudad Cuauhtémoc.
Remarks. Our specimens are a bit smaller than the measurements given by Martens (1890–1901: 114) for the species; the two largest specimens are height 1.7 and 1.7 mm, and width 2.0 and 2.1 mm with 4 whorls, Martens measurements are: height 2.0 mm, width 2 mm with 5 whorls. The aperture of the specimens from our locality is incomplete, which might explain the differences in size with those given by Martens.
Guppya cf. gundlachii gundlachii (Pfeiffer, 1840)
New record for the state
Type localities. Helix gundlachii Pfeiffer, 1840: Cuba. Synonyms: Helix pusilla Pfeiffer, 1839: Cuba. Helix simulans C. B. Adams, 1849: Jamaica (Thompson 2011).
Distribution. From Florida and Texas south to Panama, Venezuela and Trinidad and the West Indies (Thompson 2011). Chiapas (this paper): Ciudad Cuauhtémoc. This is the first record of the genus in Chiapas.
Remarks. Five specimens are juvenile, the only adult measures height 1.3 mm, width about 2.0 mm, whorls 3 3/4. Shell fragmented on the body whorl and slightly in the aperture. This species is very close in general shape to G. gundlachii which measures height 1 2/3 mm and width 2.5 mm, with 5 whorls according to Martens (1890–1901).
Guppya sp.
Distribution. Central America, Mexico, southern United States, and the West Indies (Thompson 2011). Chiapas (this paper): Custepec.
Remarks. This species of Guppya very much resembles Guppya sterkii (Dall, 1888) (from north-eastern United States), which has an imperforate depressed shell, measures 0.75 mm high and 1.22 mm wide, and has 3 1/2 whorls (Pilsbry 1946). However, the specimens at the CNMO are twice the size of G. sterkii. Our specimens also bear a depressed spire and a tiny umbilicus. Furthermore, one specimen measures 2 mm height and 3 mm width and has 4 5/6 whorls, while the second has a height of 1.5 mm and a width of 2.5 mm, and 4 whorls. This species of Guppya comes from the locality of Custepec.
Genus Habroconus Fischer et Crosse, 1872
Habroconus cf. elegantulus (Pilsbry, 1920)
New record for the state
Type locality. Mexico, San Luis Potosi, canyon and waterfalls near Valles (Thompson 2011).
Distribution. From Mexico, Central America, the West Indies to South America (Thompson 2011). Chiapas (this paper): Ciudad Cuauhtémoc.
Remarks. This species of Habroconus was found in Frontera Comalapa at the Ciudad Cuauhtémoc site of this study. The species is close to Habroconus elegantulus (Pilsbry, 1919), which has a height of 3.2 mm, a diameter of 3.3 mm, and 6 1/2 whorls. The specimens at the CNMO is 2.5 mm high, 2.5 mm in diameter, and have 4 to 5 1/2 whorls. Hence, our specimen is smaller than H. elegantulus. This is the first record of the genus in Chiapas.
Habroconus cf. pittieri (von Martens, 1892)
New record for the state
Type locality. Costa Rica, San Francisco de los Ríos near San José (Martens 1890–1901).
Distribution. Costa Rica, Nicaragua, Mexico (Thompson 2011). Chiapas (this paper): Ciudad Cuauhtémoc.
Remarks. Adult height 2.6 mm, width 3.0 mm, whorls 5 1/2, aperture incomplete; juvenile specimen of about 3 or 4 whorls, aperture fragmented. Our specimens closely resemble Habroconus pittieri in the general shape of shell, height and aperture. The specimen from near Ciudad Cuauhtémoc is about the same size of Martens’ (1890–1901) specimen, which is height 2.5 mm and width 3.5 mm, slightly wider than ours.
Family Spiraxidae H. B. Baker, 1939
Genus Euglandina Crosse et Fischer, 1870
Euglandina cf. tenella (Strebel, 1875)
New record for the state
Type locality. Mexico, Veracruz, “Callejones” forest between half an hour and an hour southeast of Veracruz City (Martens 1890–1901).
Distribution. It is found in the vicinity of Veracruz City (Thompson 2011). Chiapas (this paper): Custepec, La Perla.
Remarks. There are two specimens at the CNMO closely resembling the species E. tenella (Strebel, 1875): one is a subadult and the second is more developed. The measurements given by Strebel (1875) and Martens (1890–1901) for E. tenella present a height of 32 mm and diameter of 15 mm, height/width ratio = 2.13; our more developed specimen is 27.4 mm in height and has a diameter of 12.9 mm, height/width ratio = 2.12, so is somewhat smaller and differs slightly from E. tenella. More material is needed to finally determine the species at the CNMO.
Genus Myxastyla Thompson, 1995
Myxastyla pycnota Thompson, 1995
New record for the state and Mexico
Type locality. Guatemala, Gorge along the Selequa River, 12 km from La Democracia, Huehuetenango Dept. (Thompson 1995).
Distribution. Huehuetenango, Guatemala (Thompson 2011). Chiapas (this paper): Custepec. This is the first record of the species in Chiapas.
Remarks. The specimen at the CNMO fully matches the description of the species given by Thompson (1995).
Genus Salasiella Strebel, 1878
Salasiella cf. guatemalensis Pilsbry, 1920
Type locality. Guatemala, Gualan (Thompson 2011).
Distribution. Guatemala (Thompson 2011). Chiapas (this paper): Ciudad Cuauhtémoc.
Remarks. This specimen is close to Salasiella guatemalensis Pilsbry, 1919 (1920) in length, however, the latter species is 25% wider. The specimens available possess more slender shells when compared with S. guatemalensis. Both S. guatemalensis and our specimen have a rather large aperture, being more than half the length of the shell. The specimen from 31 December 1988 (CNMO 8340) is adult, since the interior contains the remains of an egg. The three specimens of 19 December 2018 (CNMO 8309) are just fragments (two apexes, some other pieces) and the more complete specimen has half the body whorl without the aperture. We need more material to determine if the specimens found at this site are S. guatemalensis or a new species of Salasiella.
Salasiella pfeifferi Pilsbry, 1899
Type locality. Mexico, Chiapas (Martens 1890–1901).
Distribution. Chiapas in Mexico, Costa Rica, Turubares [sic!] (Martens 1890–1901, Pilsbry 1907–1908); Jacobson (1968) also recorded the species in Nicaragua. Chiapas (this paper): La Perla. This is the first record of the species in the state of Chiapas since Martens ’ time (1890–1901).
Remarks. The CNMO Salasiella pfeifferi (as S. pulchella) specimen differs from the species description (Pilsbry 1907–1908) in the following features: it lacks the light buff streaks, and the shell height/width ratio is 2.74 versus 2.8 in the type material.
Salasiella cf. camerata H. B. Baker 1941
New record for the state
Type locality. Mexico, Puebla, Tepexic, below Necaxa; 2,200 ft. alt. (Baker 1941).
Distribution. In the state of Puebla, Mexico (Thompson 2011). Chiapas (this paper): Ciudad Cuauhtémoc.
Remarks. This species resembles Salasiella camerata Baker, 1941 in the general shape of the shell, both have a short spire and a large aperture. Nonetheless, S. camerata is two times larger, and its aperture is 80 percent the total length of the shell, while in our specimen the aperture is 78% the length of shell. The apex in S. camerata is wider and rounded, whereas in our specimen the apex is slightly more acute and slender. Table 5 summarises dimensions of the type specimen of S. camerata and those of our specimens.
Table 5
Dimensions of the type specimen of S. camerata and those of our specimens. Measurements were calculated from the drawing in Baker (1941: plate 5, figs 4 and 5). H/W – height/width ratio
Thompson (2011) refers to the species with a question mark, and in MolluscaBase Salasiella camerata is cited as taxon inquirendum, non the less our specimens show similar features as the figures showed by Baker (1941) and do not resemble any other described Salasiella. More shell material and live specimens are needed to further study the species and solve the status of Salasiella camerata.
Salasiella cf. perpusilla (Pfeiffer, 1866)
New record for the state
Type locality. Mexico, Veracruz, Mirador (Thompson 2011).
Distribution. Mexico, Guatemala and Honduras (Martens 1890–1901, Pilsbry 1907–1908). Chiapas (this paper): Las Champas.
Remarks. The flank of the shell is roundish and inclined, thus the shell narrows toward the anterior extreme. Our specimen resembles in general shape the shell of Salasiella perpusilla (Pfeiffer, 1866). Pilsbry (1907–1908) also mentioned that the species could measure 4.5 mm in height, whereas our specimen is larger by about 1 mm, as it measures in height 5.3 mm, width 2.4 mm and it has 4 whorls.
Family Thysanophoridae Pilsbry, 1926
Genus Thysanophora Strebel et Pfeffer, 1880
Thysanophora conspurcatella conspurcatella (Morelet, 1851)
New record for the state
Type locality. Mexico, Yucatán, Merida (Thompson 2011).
Distribution. Mexico (Campeche, Tabasco, Yucatán, Veracruz and Tamaulipas) and Guatemala (Thompson 2011). According to Thompson (2011) it is distributed from Tamaulipas to Yucatán and Guatemala. Chiapas (this paper): Ciudad Cuauhtémoc.
Remarks. The specimen measures: height 1.1 mm, width 1.95 mm, whorls 2 1/2. It is rather worn, but the growth lines are well marked. The single specimen from 31 December 1988 (CNMO 8332) is a young one if compared with measurements given by Pilsbry (1926), which was one whorl larger and of height 2 mm, and width 3.5 mm. It shows the fine slanting riblets of the species (Pilsbry 1940) and the distinguishing outline. Specimens from 19 December 2018 (CNMO 8326) measure: height 1.4 mm each one, width 2.3 and 2.8 mm, whorls 3 and 3 1/2. The smaller is well-preserved and shows the typical sculpture of the apex, while the larger has half a whorl broken, it is worn (weathering), and shows no sculpture of the apex.
Genus Setidiscus H. B. Baker, 1927
Setidiscus hornii (Gabb, 1866)
New record for the state
Type locality. United States, Arizona, Pinal County, Old Fort Grant, at the junction of Aravaipa and San Pedro Rivers (Thompson 2011).
Distribution. United States, Texas, New Mexico, Arizona, most of the northern states of Mexico, Baja California Sur and Nicaragua (Thompson 2011). Chiapas (this paper): Ciudad Cuauhtémoc. As far as we are able to ascertain, this is the first record of the species in Chiapas.
Remarks. Specimens show the typical features that distinguish the species, one specimen has the apex broken.
Genus Lyroconus H. B. Baker, 1927
Lyroconus cf. plagioptycha (Shuttleworth, 1854)
Type locality. Puerto Rico, Humacoa (Thompson 2011).
Distribution. The southern states of United States, Mexico, Central America, Colombia and the West Indies (Thompson 2011). Chiapas (this paper): Ciudad Cuauhtémoc.
Remarks. The shell fragment shows the slanting lines on the apex as on other species in this genus. The shell measures (approximately) height: 2.0 mm, umbilicus 0.5 mm, and it is possible to count about 3 whorls, the columella is well preserved.
INTRODUCED MOLLUSCS
Family Thiaridae Gill, 1871
Genus Melanoides Olivier, 1804
Melanoides tuberculata (Müller, 1774)
Type locality. Africa, South East Asia (Pace 1973, Welter -Shultes 2012).
Distribution. Africa, Asia, Australia, the Pacific Islands. In America it is present from Mexico and throughout Central America (Thompson 2011). Chiapas (this paper): Puente Colorado.
Remarks. This introduced freshwater species was first recorded by Abbott (1973) in Veracruz and is now widely distributed throughout Mexico (Contreras-Arquieta et al. 1995, Contreras-Arquieta 1998, Cruz-Ascencio et al. 2003, Naranjo-García & Castillo-Rodríguez 2017).
Family Achatinidae Swainson, 1840
Genus Allopeas H. B. Baker, 1935
Allopeas gracile (Hutton, 1834)
Type locality. India, Mirzapur (Pilsbry 1906).
Distribution. Cosmopolitan (Christensen & Weisler 2013). Chiapas (this paper): Ciudad Cuauhtémoc, Puente Colorado.
Remarks. Our two specimens show the similar shape of the species as illustrated by Pilsbry (1906, 1946). Measurements of our specimens are in height: 6.0 and 7.2 mm, width 1.9 and 2.2 mm, whorls 5 and 6. These two specimens are shorter than described by Pilsbry (1946) (height 10 mm, width 3 mm and 8 whorls). Our younger specimen has a finer profile; however, the sculpture is well marked.
In the study on the biology of the species, Capinera (2017) concludes that although the snail is omnivorous the quantity of foliage it consumes is not enough for it to be considered a major pest snail.
Genus Opeas Albers, 1850
Opeas hannense (Rang, 1831)
Synonym. Opeas pumilum (L. Pfeiffer, 1840)
Type locality. Senegal, Hann, western Africa (Rang 1831).
Distribution. It was found in Mexico at Baja California (Smith et al. 1990), Tabasco, as well as in Guatemala, Nicaragua and Panama; in addition, it has been introduced to other parts of the world (Thompson 2011). It is also reported from Puerto Rico (Van der Schalie 1948) and Argentina (Virgillito & Miquel 2013).
Remarks. A terrestrial species, it does not seem to be a pest, since observations of O. hannense (as Opeas pumilum) in eight greenhouses in New York City showed no damage to the foliage or blossoms of roses. In addition, the author thought that the snails may have been feeding on plants and mulch (Karlin 1956). Nonetheless, in Costa Rica this species was found to feed more frequently on the roots of Gramineae, Rubiaceae and Compositae, among others (Leandro Castaneda 1993). It is believed that O. hannense has been dispersed around the world through commerce (Pilsbry 1906, Christensen & Kirch 1981).
Genus Subulina Beck, 1837
Subulina octona (Bruguière, 1789)
Type locality. Guadalupe Island and Santo Domingo (Bruguière 1789–1792, Deisler & Abbott 1984).
Distribution. It has been registered in the United States (Florida, Philadelphia), Africa, Sri Lanka, East Indies (Pilsbry 1946), Cuba (Herrera-Uria 2016), Brazil (Oliveira et al. 2015), Argentina (Rumi et al. 2010), Malaysia (Uchida et al. 2013), Zimbabwe (van Bruggen 1981), and in Mexico in Campeche, Tabasco, Chiapas, San Luis Potosí, Tamaulipas, Veracruz, and Yucatán (Thompson 2011). Chiapas (this paper): Puente Colorado.
Remarks. This species has a tall shell (up to 17 mm) with a truncated columella. It has been introduced widely around the world. In Brazil it was found to be one of the land molluscs serving as the intermediate host of the lung worm Angiostrongylus cantonensis (Chen, 1935), the nematode responsible for eosinophilic meningitis in humans (Carvalho et al. 2012, Morassutti et al. 2014).
DISCUSSION
Twenty-nine families and 158 species (and subspecies) of terrestrial molluscs have been recorded for the state (Naranjo-García & Smith 2014, Tovar-Juárez et al. 2020), equivalent to 16.4% of the total of the non-marine mollusc fauna of Mexico. As a result of this work 23 species are new records for Chiapas, giving a total of 181 species and 32 families for the state (Naranjo-García & Smith 2014, Tovar-Juárez et al. 2020). See Table 3 for new additions, which were marked with “Chis” for Chiapas or “Mex/Chis” for Mexico and Chiapas.
Drymaeus discrepans, Lamellaxis cf. strebelianus, Myxastyla pycnota, Bothriopupa breviconus, and Paralaoma coloba are new records for Mexico, all of them were previously known from Central America (Guatemala, El Salvador and Nicaragua). Bothriopupa breviconus and Myxastyla pycnota were described in Guatemala and now are recorded for the first time in Chiapas; in addition, these three species are new records in the Mesoamerican biogeographical dominion sensu Morrone (2006).
Families of terrestrial molluscs recorded for the first time in Chiapas are: Vertiginidae (with the genera Botriopupa, Gastrocopta and Vertigo), and Punctidae (with Paralaoma coloba).
In the area considered we are recording the freshwater species Pomacea flagellata and Pachychilus indiorum (Table 2), known previously from other places in Chiapas as from the Lacandon rainforest (Bequaert 1957, Ramírez et al. 2022).
Snails present in other parts of Mexico yet recorded for the first time in Chiapas are: Mesembrinus shattucki, Glyphyalinia indentata paucilirata, Euglandina cf. tenella, Thysanophora conspurcatella conspurcatella, Gastrocopta pellucida hordeacella, Pupisoma dioscoricola dioscoricola, Guppya biolleyi, Guppya cf. gundlachii gundlachii, Habroconus cf. elegantulus, Salasiella cf. camerata and Vertigo cf. ovata.
In addition, the native species Pyrgodomus microdinus microdinus, Lamellaxis martensi martensi, and Mayabina tapanensis and the introduced Melanoides tuberculata are new records for the sites referred to in this study.
The number of species Chiapas share with its neighbours is 31 with Veracruz (of 293 species), 9 with Oaxaca, 23 with Tabasco, 19 with Campeche and 51 with Guatemala (of 292 species) (Thompson 2011). To date, the state of Veracruz has been the most studied Mexican state since the early European expeditions to the Americas (the collecting effort was the highest there) (Fischer & Crosse 1870–1902, Martens 1890–1901). Chiapas with a less strong collecting effort has 10.5% of the number of species of Veracruz, while it shares with Guatemala 17.5% of the species. With the data available until now, Chiapas shows a closer faunal affinity with that of Guatemala as was observed previously (Naranjo-García 1993).
The Custepec area has been subjected to coffee cultivation since the early XX century (Pérez-Grovas Garza 2013). Coffee, as well as cacao (Gordillo Ruiz 2013) is regularly grown under the cover of other vegetation. This type of agroforestry system closely resembles a natural forest (Tscharntke et al. 2011); hence, our results are interesting because they reflect part of the malacofauna that one could have expected in a non-developed forest.
On the other hand, the introduced Melanoides tuberculata was already present in northeastern Chiapas (Lacandon rainforest) (Ramírez et al. 2022) where the snail was not very abundant, and at Puente Colorado it was also present in low numbers and showed signs of predation. Introduced land molluscs found in this study possibly arrived through the cultivation and management of coffee plants, and pasture for cattle over the plains around Ciudad Cuauhtémoc.
