Fastosarion helenkingae Scott, 1995

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 : 409-412

Fastosarion helenkingae Scott, 1995

Figs. 6 , 7G–H , 8I–J , 12C–D , 16

Fastosarion helenkingae Scott, 1995: 75 , figs. 1c, 2 , 5b, 6; Stanisic et al., 2010: 306–307, 329.

Fastosarion schelli Stanisic, 2010 in Stanisic et al., 2010: 306–307, 328.

Material examined

Types: Holotype: MTQ MO40184 ( Bowling Green Bay NP, Mt Elliot, 19°30'S, 146°58'E).

Paratypes: MTQ MO40185-40191 (same data as holotype).

Holotype of F. schelli: QM MO 14106 (Magnetic I., MEQ, 19°08’S, 146°51’E, 200 m, 23 Sept 1980, J. Stanisic).

Paratypes of F. schelli . QM MO16161 , QM MO78893 , AM C.125918.

Non-type material: See table 1 .

Diagnosis

External morphology: Shell (fig. 7G–H) medium-sized (14.3–18.5 mm), amber, transparent, 3.2–3.7 whorls, depressedly subglobose with a low spire. Body (fig. 8I–J) 30 mm long, speckled brownish cream to grey, darker on head and tail; sometimes with a reddish sole. Shell lappets and mantle lobes large, each lappet with a ridged dark line close to and parallel with lower edge. Dark line along mantle collar. Tail weakly keeled, keel paler, slime network moderately strong.

Genital anatomy: Genitalia (figs. 12C–D, 16) with medium length vagina; bursa copulatrix moderately short, duct distinct, bursa spherical to oval. Penis long, slender, slightly swollen proximally, internally with one complete longitudinal pilaster and one short longitudinal pilaster proximally, internal wall sculptured with pustules; 60–80% of penis contained in penial tunica. Penis slightly longer than epiphallus, slightly narrower in diameter; epiphallus enters penis through a swollen ring; epiphallus 2 much longer than epiphallus 1; epiphallic caecum short; flagellum short, slender, terminal portion fused into loop. Spermatophore simple, tail-pipe mostly smooth, towards terminal end sculptured with small teeth pointing towards capsule, followed by hair-like spines pointing away from capsule on terminal portion.

Remarks

Fastosarion helenkingae is only known from the type locality, Mt Elliot NP near Townsville. Fastosarion schelli has been reported from the Townsville area, including Hervey Range, Magnetic Island and Mt Stuart ( Stanisic et al., 2010). The two taxa are very similar in external appearance, differing primarily in size, shell shape and colouration: F. schelli is larger, with a more globose shell and paler body colour ( Stanisic et al., 2010). There is also a possible ecological difference: F. helenkingae has only been found under logs in the high altitude mesophyll rainforest on the summit of Mt Elliot, while F.schelli is found semi-arboreally in dry vine thicket on granite, in the foothills of the Hervey Range and on Magnetic Island.

We have found that the two species agree very closely in reproductive anatomy, the only difference being slightly coarser pustules in the penis interior of F. schelli . They are also genetically very similar. Also, additional material examined herein includes F.helenkingae from the foothills of Mt Elliot and specimens of F. schelli from under logs. We do not believe that the minor genetic or morpho-anatomical differences warrant maintaining these taxa as separate species and we therefore treat the two names as synonyms.

Fastosarion helenkingae is allopatric with respect to its congeners. It can be distinguished from other members of Clade A by its generally smaller size and by the presence of a pigmented ridge on the shell lappets.

Figures

FIGURE 2 Majority-rule consensus tree based on Bayesian analysis of the concatenated data set of fragments of the mitochondrial genes 16S and COI. Ambiguous alignment sites in 16S removed using MAFFT. Numbers on branches indicate posterior probabilities. Scale bar indicating 40% of modelled sequence divergence. Shells shown to scale.

FIGURE 6 Distribution of Clade A species. ▲ = F.superbus, ◻ = F.aquavitae, ♢ = F.brazieri, ◆ = F.comerfordae, ●= F.griseolus, ▽ = F.helenkingae, █ = F.paluma.

FIGURE 7 Shells of Clade A species. A. Fastosarion superbus, MO77446.B. Fastosarion aquavitae, MO50851.C. Fastosarion aquavitae, MO20228 (type locality of F.ameyi). D. Fastosarion brazieri, AM C.553533.E. Fastosarion comerfordae, MO63985.F.Fastosarion griseolus, MO55568.G.Fastosarion helenkingae, NMV F219324.H. Fastosarion helenkingae, AM C.559842 (type locality of F.schelli). I. Fastosarion paluma, MO63983.J.Fastosarion paluma, MO48024 (Hinchinbrook Is).Scale bar 5 mm.

FIGURE 8 Fastosarion live images (Clade A).A.Fastosarion superbus, MO46340, Mt Dryander (QM image). B.F.aquavitae, NMV F230751, Brandy Creek (A. Moussalli, NMV).C. F.brazieri, AM C.553531, Cape Tribulation (A.Moussalli, NMV).D. F.brazieri, AM C.525003, Mt Lewis.E.F.comerfordae, Broken River NP (Kackland). F.F.paluma, Paluma (QM image). G. F.griseolus, AM C.512514,Byfield SF.H. F.griseolus, AM C.512615,Burleigh Head NP. I. F.helenkingae, NMV F219324,Bowling Green NP (A. Moussalli, NMV).J. F.helenkingae, AM C.559842, Magnetic Island (type locality of F.schelli).

FIGURE 12 Spermatophores of Clade A species. A–B. Fastosarion brazieri, MO66680.C–D.Fastosarion comerfordae, MO63985. E-F.F.helenkingae, MO47971.

FIGURE 16 Genitalia of F.helenkingae. A, C, E. MO47971, Mt Elliot. B, D. MO16161, Magnetic Is. A–B, Reproductive system.Arrows show the junction of the penis and epiphallus.C–D, Penis interior.E.Spermatophore. Scale bars 1 mm (C–E), 2 mm (A–B).