Type species: Kora corallina Simone, 2012; Recent, Brazil.

Included taxa: Kora corallina Simone, 2012 (Figs. 2, 12–14); K. nigra Simone, 2015 (Fig. 3); K. rupestris n. sp. (Figs. 4–11, 15–17).

Original diagnosis (Simone 2012: 432)

“Outline fusiform; spire tall, somewhat turriform. Protoconch simple, paucispiral, ornamented by scanty axial cords. Umbilicus narrow. Peristome somewhat away from longitudinal axis of spire. Peristome deflected. Inner lip with strong, oblique tooth in middle level.”

Emended diagnosis

Shell conical-fusiform. Color initially lighter, becoming darker towards aperture; light-colored subsutural spiral band always present. Protoconch (∼ 2 whorls) initially smooth, becoming sculptured by well-marked sinuous axial ribs later on, which gradually increase in strength until they become similar to teleoconch sculpture; proportion of whorls with and without sculpture pattern varies interspecifically and ribs of “transitional” strength might not be present. Transition from proto- to teleoconch not clearly marked. Teleoconch sculptured by sinuous prosocline axial ribs. Aperture broad, slightly expanded laterally, away from the shell axis. Peristome reflexed. Columellar lamella oblique. Umbilicus narrow, but well-marked.

Discussion

The set of diagnostic features of the genus Kora allows a clear distinction from other orthalicoid genera. The main characters are analyzed below; the most important of which is the protoconch sculpture pattern.

Shell : The shell seems to be conservative within the genus, with all species displaying a conical-fusiform shell, differing only in its proportions and absolute size. As already pointed out by Simone (2012), the degree of intraspecific conchological variation of Kora species is not high (K. corallina is known from several dozens of specimens): the variation in size is small, but shape can go from narrower to broader shells, the latter sometimes also with a broader aperture.

Color : Both K. corallina and K. rupestris n. sp. have initially light-colored shells, which become clearly darker towards the aperture. Kora nigra is more uniformly colored, although the same pattern may be observed. Variation in overall coloration and color pattern is seen only interspecifically in Kora (at least in the presently available material). A great amount of variation (both inter- and intraspecific) is common in other orthalicoid genera, such as, for instance, Drymaeus Albers, 1850 and Leiostracus Albers, 1850, but is minimal in others, such as Plekocheilus Guilding, 1828 and Dryptus Albers, 1860 (e. g., Simone 2006; Breure & Mogollón Avila 2010; Borrero & Breure 2011; Salvador & Cavallari 2013; Salvador et al. 2015). A constant feature of the genus seems to be a lighter-colored spiral band right below the suture.

Aperture : A reflexed peristome is found in all presently-known species of Kora. This is not exclusive of Kora and can be seen in many orthalicoid genera (e. g., Simone 2006), although this feature is not necessarily constant throughout each genus.

Apertural barriers : The columellar lamella seen in Kora is a recurrent feature in orthalicoid families (and its presence/absence may vary within some genera) and might not be very useful for diagnosis and phylogenetic analyses. As pointed out by Simone (2012), other Brazilian orthalicoid genera with a similar lamella are Dryptus, Plekocheilus and Eudolichotis Pilsbry, 1896. A similar lamella is known in the family at least since the Late Paleocene or Early Eocene, as shown by the fossil genus Itaborahia Maury, 1935, from Rio de Janeiro state (Salvador & Simone 2013).

Protoconch : The most characteristic feature of the genus Kora is the protoconch. The protoconch (∼ 2 whorls) is initially smooth, becoming sculptured by well-marked sinuous axial ribs later on, which gradually increase in strength until they become similar to teleoconch sculpture. The exact numbers of smooth and sculptured whorls varies interspecifically (Figs. 12–17). The transition from proto- to teleoconch is weakly marked.

On the one hand, both K. corallina (Figs. 12–14) and K. nigra have the first ∼ ¼ whorl smooth; the next ∼ 1½ whorl is sculptured by faint axial striae; close to the final ∼ ¼ whorl, these striae become more strongly marked, equal to the teleoconch's ribs. On the other hand, K. rupestris n. sp. (Figs. 15–17) has the first 1½ to 1¾ whorl smooth; the last ½ to ¼ whorl has the same strong axial ribs as the teleoconch. This means that the “transitional” faintly striated region is not usually present in K. rupestris n. sp., but a single specimen shows very faint axial striae immediately before the onset of the thicker teleoconch-like ribs.

This axial sculpture pattern of the protoconch is similar to that of the genus Naesiotus Albers, 1850 and Rabdotus Albers, 1850, with its sinuous and well-marked axial ribs (Breure 1978, 1979; Breure & Coppois 1978). Nevertheless, these two genera show the entire protoconch covered in ribs, contrary to Kora, which has a smooth region before the beginning of the ribbed area. Finally, as pointed out by Simone (2012), Neopetraeus von Martens, 1885 also has axial riblets similar to Kora, but its protoconch is also sculptured by fine spiral striae, giving it a reticulate appearance (Breure 1979).

In addition, the protoconchs of Naesiotus spp. exhibit a lower number of axial ribs than those of Kora; the number of axial ribs in the protoconch of Rabdotus spp. is intermediate between those of species of Naesiotus and Kora (Breure 1978, 1979). The pattern of the protoconch sculpture, closely reminiscent of Naesiotus and Rabdotus, might indicate the placement of the genus Kora in the family Bulimulidae (as per Breure & Romero 2012) instead of the originally proposed allocation in Orthalicidae (Simone 2012). Protoconch sculpture tends to be a good indicative of the relationship between taxa, but the family Bulimulidae also counts with genera with very distinct protoconch patterns, such as Drymaeus (Breure 1978, 1979; Breure & Romero 2012). As such, the importance of this character in the classification of the Orthalicoidea remains somewhat uncertain.

Finally, the protoconchs of Kora iracema Simone, 2015 and K. terrea Simone, 2015 exhibit a completely reticulated sculpture pattern, thus lacking the characteristic protoconch of Kora. This conformation is characteristic of the genus Drymaeus (Breure 1979). Moreover, their overall shell shape, aperture shape, lack of a strong columellar fold, and greatly reflexed peristome are also befitting of the genus (Breure 1978, 1979; Simone 2006). As such, both species are here transferred to this genus as Drymaeus iracema (Simone, 2015) n. comb. and D. terreus (Simone, 2015) n. comb.

Kora corallina: Simone 2015 [in part]: 53 (figs. 14, 22).

Holotype : MZSP 121416 (A. Bianchi col., VIII.2012; Figs. 4–7, 15–17).

Paratypes : MZSP 121441 (2 shells, from type locality; A. Bianchi col., VIII.2012; Figs. 8–9).

Additional material : MZSP 106230 (1 shell; Serra do Ramalho municipality, Gruna das Três Cobras; 14°19′S 43°47′W; alt. 440 m; M. E. Bichuette col., 10.IX.2008; Fig. 10). MZSP 107996 (1 shell; Coribe municipality; J. VAZ collection; M. U. T. Rodrigues col., I.1980; Fig. 11).

Type locality : Brazil, Bahia, Carinhanha municipality (city center coordinates: 14°18′18″S 43°45′54″W), under rocks on Canabrava Hill. Unfortunately, more precise locality data, such as coordinates and altitude, were not recorded by the collector.

Etymology

From the Latin “rupestris”, meaning “of rock”, “montane”. Reference to the rocky mount where the types were collected.

Distribution

Known only from the type locality and the neighboring municipalities of Serra do Ramalho to the north and Coribe to the west (Fig. 1).

Habitat

Caatinga shrublands.

Diagnosis

Shell slender. Shell color comprised of light tones of brown. Protoconch sculpture pattern: first 1½ to 1¾ whorl smooth; last ½ to ¼ whorl sculptured by well-marked axial striae. Aperture narrow.

Description

Shell large (∼ 35 mm), conical-fusiform, slender; greatest width on body whorl; shell width ∼ 2/5 shell length (Figs. 4–6, 8–11). Shell color light brown; last whorl increasingly darker; narrow stripe immediately below the suture slightly lighter than remainder of whorl (Figs. 4–6). Peristome white. Spire angle usually ca. 45°, but up to ca. 50° in broader specimens. Protoconch (∼ 2 whorls; Figs. 15–17) rounded; first 1½ to 1¾ whorl smooth; last ½ to ¼ whorl sculptured by well-marked axial striae (same as teleoconch); transition to teleoconch not clearly marked, prosocline, simple. Teleoconch sculptured by sinuous prosocline axial striae (Fig. 15). Whorl profile lightly convex. Suture well-marked, but not deep. Body whorl almost ⅔ shell length. Aperture oval, prosocline, proportionately large, slightly expanded laterally away from shell axis; aperture ∼ ½ shell length, ∼ ⅔ shell width. Columellar lamella well-marked, variable in size, oblique to shell axis (Figs. 4, 8–11). Peristome greatly reflexed. Umbilicus narrow (Fig. 7).

Measurements (in mm). Holotype: 6½ whorls; H = 37.7; D = 16.3; S = 19.4; S' = 13.7; h = 18.2; d = 11.4. — Paratype #1: 6¼ whorls; H = 35.5; D = 15.3; S = 18.6; S' = 12.4; h = 16.5; d = 10.7. — Paratype #2: 6¼ whorls; H = 33.3; D = 14.8; S = 17.1; S' = 12.2; h = 16.5; d = 10.2. — MZSP 106230: 6¼ whorls; H = 34.2; D = 15.9; S = 17.9; S' = 12.0; h = 15.9; d = 11.1. — MZSP 107996: 6½ whorls; H = 35.6; D = 18.2; S = 18.3; S' = 13.1; h = 17.6; d = 12.1.

Differential diagnosis

Kora rupestris n. sp. can be easily diagnosed by its different protoconch sculpture pattern (see the discussion of the genus, above, for the comparison with K. corallina and K. nigra). Moreover, K. rupestris n. sp. (Figs. 4, 8–11) has a more slender shell and spire than K. corallina (Fig. 2) and K. nigra (Fig. 3), which also results in a slightly narrower aperture; both K. corallina are and K. nigra are very broad, as also reflected in their greater spire angle values of 45–50° (K. corallina) and 60–65° (K. nigra). However, there are more slender specimens of K. corallina, which present the same shell length/width ratio as K. rupestris n. sp. Such specimens may be diagnosed by size (besides the protoconch), as the shell of K. rupestris n. sp. is smaller than that of K. corallina, having approximately ¾ of the shell length of the latter, with no overlap in their size ranges. Kora rupestris n. sp. is slightly larger than K. nigra, although some doubtful specimens of the latter (MZSP 104839) are in the upper size range of K. corallina. Furthermore, K. rupestris n. sp. shows ½ to ¾ less whorl in the teleoconch, when compared to K. corallina, although it has the same whorl count as K. nigra. Finally, the color pattern of K. rupestris n. sp. (Fig. 4) is similar in nature to that of K. corallina (Fig. 2), but it is usually comprised of overall lighter tones of brown; K. nigra has a more homogenous dark coloration (Fig. 3).

The single specimen (MZSP 106230) recovered in a cavern and identified by Simone (2015: figs. 14, 22) as K. corallina, in fact belongs to K. rupestris n. sp. It agrees with K. rupestris n. sp. in size, overall shape and, more importantly, the protoconch sculpture pattern. This single specimen is slightly broader than the type specimens of K. rupestris n. sp., with a narrower umbilicus, proportionately smaller aperture and displaying a stronger white parietal callus. Nevertheless, this same kind and extent of variation is seen in the type series of K. corallina, and is thus considered here intraspecific variation of K. rupestris n. sp.