Holotype (NMBE 549920/1 ex AJC 1444): USA, Georgia, Flovilla, Butts County, Indian Springs State Park; N 33.242367 W -83.92035; under moist leaf litter in drainage basin; 5 April 2010; leg. Adrienne Jochum.

Figure 4. 

Carychium hardiei sp. n. A–F holotype (NMBE 549920/1) G–L paratype shell (NMBE 549921/8). Scale bar 1 mm.

Figure 5. 

Carychium hardiei sp. n. A–FCT scans showing columellar apparatus of paratype (NMBE 549921/8) G umbilical view H aerial view of protoconch and spire. Scale bar 1 mm.

Paratypes: locus typicus 8 shells (NMBE 549921/8 ex AJC 1444); 8 specimens in alcohol (NMBE 549922/8 ex AJC 1444); 8 shells (SMF 341638 ex AJC 1444); 7 shells (ANSP 467825 ex AJC 1444); 7 shells (CM 155814 ex AJC 1444); 6 shells (UF 489973 ex AJC 1444); 24 shells previously preserved in formalin and dried (AJC 1445); data as the holotype.

Shell ca. 1.75 mm in height, transparent, elongate-pupiform with an entire, elliptical-oblique, moderately thickened peristome, including a small, deeply set parietal denticle and a slight columellar-basal callus.

(material from type locality). Measurements of holotype and paratypes are provided in Table 2.

Shell minute, elongate-pupiform, pellucid when fresh, opaque shiny when older. Aperture elliptical-oblique, somewhat higher than wide, taking up less than one third the shell height, outer lip moderately reflected, thin above, increasingly thickened on its outermost extension by a heavy deposit of callus upon its surface and inner edge; columellar margin has a callus and an acute entering fold above. Whorls convex, moderately rounded, ranging from 4.8–5.4 in number. Suture deep. Protoconch bulbous. Teleoconch sculpture consists of weak, irregular oblique striae. Maximum width of body whorl extends 1/6 beyond the rim of the peristome in side view facing left (Fig. 4D, L). Palatal rim appears alabaster-like. In profile view facing left, the peristome of the mature shell gently curves in at the upper edge, expands moderately and then bends gently back at the base of the shell in alignment with the central axis (Fig. 4D, L). A small, deeply set, parietal denticle is almost centrally positioned on the parietal face (Fig. 4A, I). The tiny, deeply set parietal denticle is partially visible in umbilical view (Fig. 5G). Internally, from the dorsal and aperture-facing-right perspectives, the columella bears a single, simple elongate lamella beginning one third the distance from the top of the penultimate whorl (Fig. 5B–C, F), which elaborates into a characteristic, broadly winged, tongue-like structure in aperture-facing-left position (Fig. 5D). In ventral perspective, the lamella is slightly sinuate, whereby the first thickened flexure directed upward is in alignment with the columellar axis (Fig. 5A). The lamella culminates at the base of the gently twisted columella as a small, deeply set, well-formed, non-sinuous denticle. The base of the columella spindle (portion under the tongue-like lamella) is moderately long and dilated by the final manifestation of the columellar lamella forming the parietal denticle (Fig. 5E–F).

Differs from Carychium floridanum G.H. Clapp, 1918 (Figs 6–7) by the more bulbous protoconch, the thinner, less rounded and less swollen peristome, the enhanced elaboration of sinuosity and thickness of the columellar lamella (interior ventral view) and the downward projection of the lamella in tongue-like form, the presence of the parietal denticle in umbilical view and the reduced size of the deeply-set parietal denticle; from C. mexicanum (RBINS 10591.2, “Texolo Falls, V. Cruz [Veracruz], Mexico” (Pilsbry 1948)) (Figs 2A–E, 8–9) by its larger and more tapered shell, the thinner, less swollen peristome, the first flexure of the sinuate lamella synchronal with the shell axis as seen in the interior ventral view, the more elaborate configuration of the columellar lamella (in side view-left perspective) and the tininess of the parietal denticle; in C. costaricanum (RBINS 10591.1), “San José Plateau Costa Rica” (E. von Martens 1898) (Figs 2F–I, 9), the shell is more robust with increased roundness of the whorls, the aperture is markedly more auriform, the peristome is greatly thickened (swollen) and rounder with a thick columellar-basal callus in the inner left-hand corner, the columellar lamella is simple and smooth without wing-like elaboration, the parietal denticle is thick and less finely defined as in C. hardiei.

Figure 6. 

Comparative material, Carychium floridanum Clapp, 1918 (CM 46540). A–H syntypes and specimen information; E peristome with thick parieto-columellar callus and prominent parietal denticle. Scale bar 1 mm.

Figure 7. 

Comparative material, Carychium floridanum Clapp, 1918 (CM 46540). A–FCT scans showing columellar apparatus and simple lamellar sinuosity of syntype C moderately thickened S-shaped lamella A, E zones of increased callus concentration on the peristome G umbilical view showing turned back rim of peristome. Scale bar 1 mm.

Figure 8. 

Comparative material, Carychium mexicanum Pilsbry, 1891 (AJC 2092) from Puebla, Mexico. A–L fresh shells collected proximal to topotypic locality (Orizaba, Mexico) A, I–J degrees of variation in apertural barriers. Scale bar 1 mm.

Figure 9. 

Comparative material, Carychium mexicanum Pilsbry, 1891 (AJC 2092) from Puebla, Mexico A, C, E, G, I, K and topotypic C. costaricanum E. von Martens, 1898 (AJC 2093) B, D, F, H, J, L; A–LCT scans showing columellar apparatus and configuration of the columellar lamella in both species A–L. Scale bar 1 mm.

DNA barcode data can clearly delineate Carychium hardiei sp. n. from all other North and Central American taxa, demonstrating its lowest K2P genetic distance of 5.4 % to C. exile (Fig. 3). For comparison, the genetic distances between individuals of the two widely distributed European species Carychium minimum O. F. Müller, 1774 and Carychium tridentatum (Risso, 1826), for which the most sophisticated DNA barcode dataset exists (with more than 270,000 pairwise estimates), are always ≥ 4.3 %, and within-species K2P genetic distances not above 3.4 % (Weigand et al. 2014).

The new species is named after the American chemical engineer, naturalist, field biologist and long-time friend of the first author, Frank Hardie of South Carolina. Frank’s tireless hours in the field contributed substantially to the Carychium dataset encompassed in Weigand et al. (2011, 2013) as well as to the burgeoning dataset of our ongoing investigation of the Carychiidae. Without his dedication and perseverance in the field, the genus Carychium would be remarkably poorer for it. In accordance with Mr. Hardie’s heritage in the southeastern USA, we gratefully dedicate Carychium hardiei from the American southeastern State of Georgia in his name.

This species is only known from the type locality at Indian Springs State Park, ca. 90 km south of Atlanta, Georgia. The drainage basin where these individuals were collected was located proximate to the park entrance and adjacent to the latrine complex (Fig. 10). It remains questionable whether any of the so-called C. mexicanum distributions included in Hubricht (1985) for the southeastern United States include C. hardiei sp. n. Moreover, Hubricht (1985) explicitly states that faunistic surveys were largely lacking in the State of Georgia and thus, the existence of C. hardiei sp. n. could well have been overlooked completely.

Figure 10. 

Type locality of Carychium hardiei sp. n., Indian Springs State Park, Flovilla, Georgia, USA. A collector A. Jochum; B Carychium hardiei in action on rotten leaf.

Mixed deciduous leaf litter.

In the drainage basin where this species was found (see above), live individuals occurred in relative abundance, suggesting that C. hardiei has optimum ecological conditions to survive there. Still, on a global scale, its current distribution may be limited to the 2.14 square kilometres of woodland in the middle of Georgia, regarded as Indian Springs since 1825 and as a “State Forest Park” since 1927. In conjunction with the Guidelines for the IUCN Red List (IUCN Standards and petitions Subcommittee 2014) it likely constitutes a Critically Endangered narrow range endemic (CR B1). Habitat disturbance by pollution and human encroachment via tourism or urban development may pose the greatest threat.

In a subsequent study of the degrees of morphological variation observed in Carychium exiguum var. mexicanum Pilsbry, 1891, Pilsbry (1948) introduced the description “Carychium exile mexicanum” to make a point while comparing the variations of Carychium exile H.C. Lea, 1842 forms collected in Texas with those from the southern extension of the Carychium exiguum var. mexicanum range. This temporary and awkward nomenclatural construction was subsequently used by Weigand et al. (2013) when these authors assessed their material, overlooking Pilsbry’s (1948) momentarily useful, but erroneous nomenclatural construction in naming the respective morphospecies for the evolutionary lineages C1 and C4 from northern Georgia, Alabama and northern Florida. Regarding C. hardiei sp. n. and our investigations of C. mexicanum here, Pilsbry’s (1948) considerations were very insightful and are still relevant considering his broader observation of southern forms (diversity) in what we now see, using cutting-edge methods, as taxonomically unrecognized species. For Carychium exiguum var. mexicanum, Pilsbry (1948) concluded “It is the tropical representative of the exile stock and probably to be considered a southern subspecies of that, intergrading with it in Texas.”

Since Pilsbry’s (1891) initial description of “Carychium exiguum var. mexicanum” from “Orizaba, Mexico”, the distribution of Carychium mexicanum has up to now, spanned across the southern United States from Georgia and Florida west to Texas (Hubricht 1985), and south to Guatemala (Thompson 2011). However, in context of Weigand et al.’s (2013) recent molecular investigation (based on COI, 16S and H3) and our use of CT scans to assess shell morphology here, we are clearly dealing with separate species. Moreover, this work not only corroborates Pilsbry’s astute morphological observations, but also, shows that what he considered as subspecies were indeed different entities we now consider separate lineages quite distinct from the “true” C. mexicanum collected in Mexico.

Holotype (NMBE 549923/1 ex AJC 1588): Belize, Maya Mountains, Toledo District, Forest Hill, Bladen Nature Reserve; N16.557167, W-88.707833, alt. c. 404 m, in wet depressions between layers of moist leaves; 12 July 2012; leg. Dan Dourson.

Figure 11. 

Carychium belizeense sp. n. A–F holotype (NMBE 549923/1) G–L paratype shell (NMBE 549924/8) A, I prominent parietal denticle and parieto-columellar callus. Scale bar 1 mm.

Figure 12. 

Carychium belizeense sp. n. A–LCT scans showing columellar apparatus of paratype (NMBE 549924/8) C–D two-tiered, tightly coiled columellar lamella and prominent parietal denticle I–J highly sinuate tongue-like primary lamella tightly arching over swollen secondary lamella. Scale bar 1 mm.

Paratypes: locus typicus: 8 shells (NMBE 549924/8 ex AJC 1588) (2 CT-scanned) and 5 specimens in alcohol (NMBE 549925/5 ex AJC 1589); 5 shells (SMF 341639 ex AJC 1589); 4 shells (UF 489972 ex AJC 1589); 4 shells (CM 155815 ex AJC 1589); 6 specimens in alcohol (ANSP A24823 ex AJC 1588); data as the holotype.

Shell c. 1.75 mm in height, elongate-pupiform with an elliptical-shaped aperture, pellucid, thick peristome with a columellar-basal apertural barrier and a pronounced parietal denticle. Although it bears one more whorl than C. costaricanum, it is smaller than this species but larger than C. mexicanum. Internally, C. belizeense has a highly sinuate, tightly coiled, two-tiered columellar configuration.

Measurements are provided in Table 2. Shell minute, elongate-pupiform, transparent when fresh, robust, with about 4–5 highly convex whorls and a deeply incised suture; with irregular striations or blunt growth lines on the body whorl. Protoconch bulbous. Teleoconch is irregularly smooth with course texture and vague indentations disrupting the overall glossy sheen. Peristome elliptical and thick, only slightly higher than wide, closely adhering to spire, taking up about one third of the shell height, moderately reflected, projecting beyond shell (Fig. 11C, K) and curved back in profile view (Fig. 11D, L). Columellar margin has a large callus and an acute entering fold above. Parietal denticle thick, downward projecting, prominently visible from the umbilical perspective (Fig. 11E, G). Columella two-tiered with two, sinuous, thin, tightly coiled lamellae culminating in the thick parietal denticle (Fig. 12A–D). In dorsal perspective, the columellar lamella slants directly diagonal with its thickest part at the bottom end and projecting moderately from the columella (Fig. 12E–F). Remarkable is the side perspective with aperture facing right (Fig. 12I–J), whereby the columellar lamella takes on a strongly curved tongue-like form directly over the dense, blister-like second lamella of the two-tiered columellar apparatus. The base of the columella spindle is short and obliquely set. The high degree of sinuosity and tight coiling of the two-tiered lamella is remarkable for this species.

Differs from C. hardiei sp. n. by its generally more robust and fatter shell, greater degree of whorl convexity and general reduction of distinct striation on the teleoconch. In side view aperture-left profile, the peristome of C. belizeense is practically sheer with the convexity of the body whorl whereby in C. hardiei, the body whorl projects c. 1/6 beyond the rim of the peristome. The columellar callus on the inner edge of the peristome of C. belizeense is much more prominent than in C. hardiei as is the remarkably thick and prominent parietal denticle. Internally, by the highly sinuate, tightly coiled two-tiered columellar configuration versus the singular and simple, moderately sinuate lamellar configuration of C. hardiei; from C. floridanum by the increased convexity of the body whorl giving the impression of a fatter shell, by the decreased concentration of callus in the interior part of the outermost peristome rim causing less an alabaster-like appearance in the side view, aperture-facing-left perspective. Internally, by the highly sinuate, tightly coiled, two-tiered columellar configuration versus the singular and sinuate lamellar configuration of C. floridanum; differs from C. mexicanum by the more elongate shell and the possession of an additional whorl, by the uneven roundish, flat expanse of the peristome onto the body whorl whereby, in C. mexicanum, this feature seems to vary from a straight seam on the surface of the body whorl (Fig. 8A) to a fully-callused expansive peristome with a straight seam as in C. costaricanum (Figs 2F, 8I). The parieto-columellar callus is more pronounced in both C. mexicanum and C. costaricanum. Internally, the highly sinuate, tightly coiled, two-tiered columellar configuration of C. belizeense is greatly elaborate (Fig. 12C–D) compared to the less complex, and smoother sinuosity of the lamellar configurations of C. mexicanum and C. costaricanum (Fig. 9). In C. mexicanum, the narrow lamella unfolds mid-way from within the penultimate whorl position into a moderate tongue-like projection (Fig. 9E, G), maintaining a slightly thickened S-shaped sinuous form when turning the shell from dorsal (Fig. 9E–G) to aperture-right perspective (Fig. 9I), whereby for C. costaricanum, the lamella is wider at its source in the penultimate whorl, descending smoothly without elaboration. The parietal denticle in C. belizeense is stronger and larger than in both C. mexicanum and C. costaricanum. Carychium jardineanum is conchologically distinct from C. hardiei in that it is more tapered, more elongated and slender in form, clearly ribbed and bears one additional whorl.

DNA barcode data can clearly delineate Carychium belizeense sp. n. from all other North and Central American taxa, demonstrating its lowest K2P genetic distance of 3.9 % to C. costaricanum and C. jardineanum (Fig. 3), respectively.

The new species is named after Belize, the Central American country of origin.

Only known from the type locality.

Tropical rainforest and karst geology of the eastern slopes of the Mayan Mountain Divide (Dourson and Caldwell 2017).

Carychium belizeense sp. n. is so far only known from the Bladen Nature Reserve (BNR). Since it was found abundantly and is considered “a fairly common species where it is found living between layers of moist leaves” (Dan Dourson pers. comm.) it is likely not immediately threatened on the highly protected Bladen Nature Reserve. Still, on a global scale, its current distribution is probably limited to the 400-square km comprising the BNR and thus, it constitutes an Endangered narrow range endemic (EN B1) in conjunction with the Guidelines for the IUCN Red List (IUCN Standards and petitions Subcommittee 2014). Since the Bladen Nature Reserve is a major conservation priority in Belize, we are confident C. belizeense sp. n. is thriving well because of this protection.

The primary upper columellar lamella is incredibly thin, almost like gauze at the line of flexure where it projects away from the columella (Fig. 12A–B). Two scans were necessary to interpret the correct position and fragility of this structure (one slightly damaged in the process). The high extent of sinuosity is remarkable for this species.

In their upcoming publication, Daniel C. Dourson and Ronald S. Caldwell (2017) mention “in the first few whorls, there are minute spiral papillae (beads) which can only be seen under high magnification” (Dan Dourson pers. comm. 2013). In our CT scans, we cannot detect this feature. If pitting on the protoconch is meant here, and only detectable via SEM, this is a common character known throughout the Carychiidae (Burch and Schrader van Devender 1978, Bank and Gittenberger 1985, Jochum 2011) and not unique to this species.

Internally, Carychium belizeense is conchologically quite different from all other North American and Central American species hitherto described. In shape and shell robustness, it lies between C. mexicanum and C. costaricanum. Carychium jardineanum is conchologically distinct from C. belizeanum in that it is more tapered, elongate and slender in form, clearly ribbed and bears an additional whorl.

Holotype (NMBE 549926/1 ex AJC ex AJC 1902, slightly damaged): Panama, Chiriquí Province, Boquete, path near Boquete; N8.824767, W-82.495833, on moist stick; 12 June 2011; leg. Eugenia Zarza.

Figure 13. 

Carychium zarzaae sp. n. A–F holotype (NMBE 549926/1) G–L paratype shell (NMBE 549927/1). Scale bar 1 mm.

Figure 14. 

Carychium zarzaae sp. n. A–DCT scans showing columellar apparatus of paratype (NMBE 549927/1) D–F prominent parietal denticle. Scale bar 1 mm.

Paratypes: locus typicus: 1 shell (NMBE 549927/1 ex AJC 1902) slightly damaged (CT-scanned) and 1 shell formerly in formol (SMF 341640 ex AJC 1903); 1 shell formerly in formol (CM 155816 ex AJC 1903); data as the holotype.

Shell c. 1.72 mm in height, opaque, elongate-pupiform with an entire, elliptically shaped and thickened peristome, with a palatal callus, columellar-basal callus and a moderately sized, parietal denticle.

Measurements are provided in Table 2. Shell minute, elongate-pupiform, opaque, very thin, with about 4.25 convex whorls and a deeply incised suture; with irregular striations or blunt growth lines on the body whorl. Protoconch bulbous. Teleoconch is smooth with glossy sheen. Peristome elliptical and thickly doubled by callus below the palatal bulge (not denticle), only slightly higher than wide, taking up more than one third of the shell height, moderately reflected and curved back at the base (Fig. 13C, I–K). Columellar margin has a parietal-columellar callus. Parietal denticle deeply set and moderately thick, slightly downward projecting and prominently visible from the umbilical perspective (Fig. 14 F). Internally, C. zarzaae sp. n. has a very thin sinuous lamella starting at the upper third of the penultimate whorl and forming a moderate tongue-like configuration in the body whorl in dorsal perspective (Fig. 14C). Under the sinuous lamella, the elongated columellar spindle twists smoothly, forming the columellar basal callus at its proximal end (Fig. 14B–C). In dorsal and side-ventral perspectives (Fig. 14C–D), the columellar lamella forms an oblique, elongated S form with its thickest part forming the rim of the distal portion and projecting moderately from the columella (Fig. 14D).

Differs from C. hardiei by its very thin shell, rounder whorls and general reduction of marked striation on the teleoconch. In side view aperture-left profile, the body whorl of C. zarzaae projects c. 1/8 beyond the rim of the peristome. The shell of C. zarzaae is smaller and thinner than C. costaricanum and larger and thinner than C. mexicanum. The parietal denticle and the parieto-columellar callus on the peristome of C. zarzaae are not prominent as in C. belizeense (Fig. 11A, E, I) but larger than in C. hardiei (Figs 4A, I, 5A, E) and most similar to those in C. mexicanum (Puebla) (Fig. 8I–J). The increasing sinuosity of the lamella as it continues into the body whorl in the uppermost part of the penultimate whorl (in the dorsal perspective) of C. zarzaae is similar to that of C. hardiei and not to C. mexicanum nor to C. costaricanum (Fig. 9G–H). However, in C. zarzaae, the thickness of the lamella and the degree of horizontal lamellar extension is reduced in comparison to this structure in C. hardiei (aperture right and left views Fig. 5C–D); differs from C. mexicanum by the fatter shell and the reduced parieto-columellar callus seen in some shells from the Puebla C. mexicanum population (Fig. 8I–J), by the uneven thickness of callus on the peristome at the palatal mid-section and where it curves back at the basal palatal margin; from C. costaricanum by the greatly reduced robustness of the shell and the imbalanced distribution of callus on the peristome. The elongated S-shaped lamella in C. zarzaae is most similar to that in C. mexicanum. The shell of C. zarzaae is homogeneously compact in contrast to the elegantly slender, tapered form of C. jardineanum, which also bears nearly six whorls compared to the 4.25 in Z. zarzaae.

DNA barcode data can clearly delineate Carychium zarzaae sp. n. from all other North and Central American taxa, demonstrating its lowest K2P genetic distance of 4.1 % to C. jardineanum (Fig. 3).

The new species is named after our Mexican colleague and previous coauthor, Eugenia Zarza, who collected the Panamanian material in Weigand et al. (2013) and subsequently, the Mexican material here. Without her perseverance in the field, we could not have molecularly corroborated Pilsbry’s (1948) morphological investigations, nor had enough comparative material to adequately assess C. belizeense. Her field work has opened a new window to Mexican and Central American carychiid diversity and extended the distribution of this genus to its southern-most point in the Western Hemisphere.

Only known from the type locality.

Tropical rainforest.

Carychium zarzaae is only known from Boquete. Consequently, and in conjunction with the Guidelines for the IUCN Red List (IUCN Standards and petitions Subcommittee 2014), it is a Critically Endangered narrow range endemic (CR B1) and as such, warrants immediate conservation priority.

The very thin shell of C. zarzaae contrasts remarkably with the pre-sequence images of the seemingly robust shell of the second Panamanian lineage C12 (Fig. 14), which resembles C. belizeense in peristome formation and C. hardiei in superficial teleoconch striation. Although somewhat hazy in these images, C12 shows a prominently thickened parieto-columellar callus and a thick parietal denticle in congruence with that in C. belizeense. Carychium zarzaae is distinct from this joint Panamanian species. The columellar lamella of C. zarzaae is incredibly thin, almost like ripped gauze at the line of flexure where it projects away from the columella. In our experience, C. zarzaae has the thinnest shell so far encountered within the genus Carychium.

Figure 15. 

Evolutionary Lineage (EL) C12 (Weigand et al. 2013). A–I Panamanian snails before sequence procedures. Scale bar 1 mm.