Auriculella perversa Cooke, 1915

Yeung, Norine W., Slapcinsky, John, Strong, Ellen E., Kim, Jaynee R. & Hayes, Kenneth A., 2020, Overlooked but not forgotten: the first new extant species of Hawaiian land snail described in 60 years, Auriculella gagneorum sp. nov. (Achatinellidae, Auriculellinae), ZooKeys 950, pp. 1-31 : 1

Auriculella perversa Cooke, 1915 Figures 1D , 3G, H , 4D , 5D

Auriculella perversa Cooke in Pilsbry & Cooke, 1915: 90-91, pl. 25, figs 3, 4; Cowie et al. 1995; 77; Johnson 1996: 193; Severns 2011: 210, pl. 82, fig. 2.

Type material.

Lectotype: USA • 1; H = 4.7 mm, W = 3.3 mm, AH = 2.2 mm, AW = 2.0 mm, WH = 5.1; Honolulu County, Oahu, Koolau Mountains, Nuuanu; Ridge 9, east side, on Passiflora foetida ; Cooke leg.; BPBM 42384, here designated.

Paralectotypes: USA • 1; Honolulu County, Oahu, Koolau Mountains, Nuuanu; Ridge 9, east side, on Passiflora foetida ; Cooke leg.; BPBM 42385.

Paralectotypes not examined: ANSP 91817 (6 spm), ANSP 108272 (13 spm), ANSP 163399 (1 spm), ANSP 163411 (5 spm), MCZ 73044 (2 spm), SMF 7090 (1 spm).

Type locality.

Oahu: Nuuanu. See

Remarks.

Diagnosis.

Shell. Shell sinistral with inflated whorls, H = 4.4 ± 0.26 mm, W = 3.0 ± 0.23 mm, WH = 5.2 ± 0.08, AH = 2.0 ± 0.18 mm, AW = 1.4 ± 0.08 mm (Table 2 ). Columella in juveniles with a strong lamella that is reduced and covered by a thickening of the inner edge of the lip in adults. The columellar thickening usually bears an axially oriented ridge. Adults do not show a short projection or angulation where the columellar lamella was located. Parietal lamella is smooth and not undulate, extending 0.3 to 0.5 whorls into the aperture. Shell color is solid brown to dark brown with darker brown axial bands (Fig. 3H ).

Reproductive system. Phallus retractor muscle relatively short attached apically to a short and poorly defined epiphallus (Fig. 4D ). Appendix is as long as the phallus and a bit over half the diameter of the phallus at its attachment, narrowing abruptly at ⅓ its length and remaining narrow to its terminus. Phallus is broad, narrowing only slightly at the junction with the short atrium. Vagina is short.

Radula . Radula with an irregular rachidian flanked on either side by rastriform marginal teeth, as diagnostic of the family (Fig. 5D ). Each tooth has a long narrow base that expands slowly for ¾ of the length of the tooth before reaching the forward curving cusps, which comprise the remaining ¼ of the tooth. There are three long cusps at mesocone, endocone, and ectocone positions with two or more alternating larger and smaller cusps intercalated between them. There are roughly 127 teeth per row (N = 4; Table 2 ).

Distribution and ecology.

Auriculella perversa is endemic to Oahu’s southern Koolau Mountain Range (Fig. 1D ), recorded from 61 m to 914 m elevation. Auriculella perversa is arboreal and found on Clermontia sp., Cordyline fruticosa , Dubautia laxa , Freycinetia arborea , Metrosideros polymorpha , Musa sp., Pritchardia sp., Psidium guajava , and unspecified ferns, tree trunks, and dead leaves. Prior to our recent surveys the last live specimens were collected in 1939 by O.H. Emerson, E.H. Bryan Jr., and D. Anderson on Kulepeamoa Ridge in the southern Koolau Mountain Range, and the only known extant population recorded occurs in Tantalus.

Remarks.

A holotype was not designated in the original description and the type series came from two different localities: Nuuanu collected by Cooke, and Kuliouou collected by Thaanum. Two figures were provided with the original description (Pilsbry and Cooke 1915: pl. 25, figs 3, 4) for material from Nuuanu at BPBM. However, the figure caption does not indicate type status or lot numbers. The BPBM ledger in Cooke’s handwriting lists: BPBM 42384 “holotype”, figs 3, 4; BPBM 42385, “paratypes”. The BPBM ledger documents that BPBM 42385 was also the source of MCZ 7034 and SMF 7090 (Zilch, 1962: 78). The ANSP online catalog list additional specimens from BPBM and labeled as syntypes: ANSP 163411, 91817, Nuuanu; ANSP 163399 Kuliousu [sic]. ANSP 108272 Kuliouou was collected by D. Thaanum. Johnson (1996: 193) stated that the “holotype” was BPBM 42384 based on its specimen label. However, it is clear that the original description was based on multiple specimens which should be considered syntypes. We here designate BPBM 42384 as the lectotype. As a result of this lectotype designation the type locality is restricted to Nuuanu.

Unlike A. minuta , the shell of A. perversa is sinistral. The columella bears an axially oriented ridge unlike all other species in the perpusilla group. The palatal lamella is smooth and not undulate like A. gagneorum sp. nov. The reproductive system includes a short and poorly defined epiphallus and an appendix that narrows abruptly at approximately ⅓ its length. The epiphallus is short and poorly defined unlike the long epiphallus of A. perpusilla or the short but well-defined epiphallus of A. minuta and A. gagneorum sp. nov.

Figures

Figure 1. Distributional map of Auriculella spp. A Auriculella auricula B Auriculella minuta C Auriculella perpusilla D Auriculella perversa E Auriculella tenella and F Auriculella gagneorum sp. nov. Dark grey circle = historical; light grey triangle = since 2010.

Figure 3. Comparative shell morphology of A Auriculella auricula neotype BPBM 18709 B Auriculella auricula shell variation (left to right) BPBM 12651, BPBM 12666 C Auriculella minuta lectotype BPBM 42377 D Auriculella minuta shell variation (left to right) BPBM 12804, paralectotype MCZ 73037 E Auriculella perpusilla holotype MCZ 39912 F Auriculella perpusilla (left to right) BPBM 285806, BPBM 134341 (2 spm), BPBM 134280 white one, BPBM 122643, BPBM 13443 G Auriculella perversa lectotype BPBM 42384, 3 shells H Auriculella perversa shell variation (left to right) paralectotype ANSP 91817 I Auriculella tenella lectotype BPBM 18943 J Auriculella tenella shell variation paralectotype BPBM 109679 K Auriculella gagneorum sp. nov. holotype (BPBM 285843) and L Auriculella gagneorum sp. nov. paratypes, left to right (BPBM 285797, 285794, 285795, 285798). Scale bar: 5 mm.

Figure 4. Comparative reproductive anatomy of A Auriculella auricula BPBM 119141 B Auriculella minuta BPBM 99146 C Auriculella perpusilla BPBM 93626 D Auriculella perversa BPBM 97904 E Auriculella tenella BPBM 211034 F Auriculella gagneorum sp. nov. paratype BPBM 285800. Abbreviatons for reproductive structures are: AG = albumen gland; AP = penial appendix; BC = bursa copulatrix; EP = epiphallus; GP = gonopore; P = penis; OV = free oviduct; PG = prostate gland; PR = penial retractor muscle; UT = uterus; VD = vas deferens. Scale bar: 1 mm.

Figure 5. Comparative radular morphology of A A. auricula B A. minuta C A. perpusilla D A. perversa E A. tenella F A. gagneorum sp. nov. Scale bar: 10 μm.