Fastosarion insularis, Hyman & Köhler, 2019

Hyman, Isabel T. & Köhler, Frank, 2019, Phylogeny and systematic revision of the helicarionid semislugs of eastern Queensland (Stylommatophora, Helicarionidae), Contributions to Zoology 88 (4), pp. 351-451 : 424

Fastosarion insularis sp. nov.

Figs. 18 , 19E , 25

Etymology

From insularis (Latin = of an island), referring to the island habitat of this species; adjective.

Material examined

Types: Holotype: QM MO85836 ( Palm Island , site 4, NEQ, coll. 22 Feb 2001, G. Monteith) .

Paratype: QM MO76362 (same data as holotype) .

Non-type material: See table 1 .

Diagnosis

External morphology: Shell (fig. 19E) small (9.1–9.4 mm), pale amber, transparent, 2.8–3.2 whorls, flattened, thin, last whorl large. Body 16–19 mm, colour (in alcohol) brown with tiny white specks; dark bands on either side of neck; sole pale. Mantle lobes and shell lappets moderately large, covered with small white pustules, both lappets with horizontal ridge near lower edge, left lappet only with dark band below ridge.

Genital anatomy: Genitalia (fig. 25) with long vagina; bursa copulatrix moderately short, duct distinct, bursa triangular. Penis very large, swollen proximally, internally with 3 longitudinal pilasters; internal wall smooth; 85–90% of penis contained in penial tunica. Epiphallus approx. 1.5–2 times length of penis; epiphallus 1 shorter than epiphallus 2; epiphallic caecum medium length; flagellum short, slender.

Remarks

Fastosarion insularis (referred to above as ‘ Helicarionidae sp. Palm Island’) is only recorded from Palm Island in northeastern Qld (fig. 18) and is parapatric with respect to its congeners. It is most closely related to F. alyssa , which it greatly resembles, but can be distinguished by the presence of small white pustules covering the shell lappets and lobes, less distinct slime grooves, and a less transparent shell, as well as its distinct genital anatomy.

Figures

FIGURE 18 Distribution of Clade B species. █ = F.alyssa, ▼ = F.deensis, × = F.ephelis, ♢ = F.hannianus, ▲ = F. insularis, ◻ = F.katatonos, ∆ = F.longimentula, ● = F.mcdonaldi, ♠ = F.minerva, ◆ = F.papillosus, ♣ = F.pustulosus, ♥ = F.rowani, Ǫ = F.sarina, ▽ = F.tuljun.

FIGURE 19 Shells of Clade B species. A. Fastosarion alyssa (type locality of D.peterbrocki), NMV F230748. B. Fastosarion deensis, MO85834 (holotype). C. Fastosarion ephelis, MO85835 (holotype). D. Fastosarion hannianus, MO56684.E. Fastosarion insularis sp. nov., MO76354. F. Fastosarion katatonos, MO85837 (holotype). G.Fastosarion longimentula, MO65313.H. Fastosarion mcdonaldi, MO50434.I. Fastosarion minerva, MO78358. J.Fastosarion papillosus, MO78896 (Mt Superbus).K.Fastosarion papillosus, MO62397 (Kroombit Tops). L.Fastosarion pustulosus, MO78894 (Kalpowar SF).M. Fastosarion rowani, MO85839 (holotype). N. Fastosarion sarina, MO85840 (holotype).O. Fastosarion tujun (Denham Range), MO76081 (holotype). Scale bar 5 mm.

FIGURE 25 Genitalia of F.insularis, MO85836, Palm Island. A. Reproductive system.Arrow shows the junction of the penis and epiphallus.B.Penis interior. Scale bars 1 mm.