Phylogeny and systematic revision of the helicarionid semislugs of eastern Queensland (Stylommatophora, Helicarionidae)
Author
Hyman, Isabel T.
Author
Köhler, Frank
text
Contributions to Zoology
2019
2019-10-03
88
4
351
451
http://dx.doi.org/10.1163/18759866-20191416
journal article
268615
10.1163/18759866-20191416
6388d839-a72d-4598-a141-053897bfc900
1875-9866
8343061
1935CAD4-4BD5-450D-92AC-63D1A5D84CD9
Fastosarion
Iredale, 1933
Fastosarion
Iredale, 1933: 37
.
Type
species
Vitrina superba
Cox, 1871
(by original designation); masculine.
Vercularion
Iredale, 1933: 38
(name unavailable, no description). Intended
type
species
Helicarion bullaceus
Odhner, 1917
(by original designation); masculine.
Eungarion
Stanisic, 1993: 27
.
Type
species
Eungarion mcdonaldi
Stanisic, 1993
(by original designation); masculine.
Dimidarion
Stanisic,
2010
in
Stanisic et al., 2010: 314
.
Type
species
Dimidarion alyssa
Stanisic, 2010
(by original designation); masculine.
Hymanarion
Stanisic,
2010
in
Stanisic et al., 2010: 318
.
Type
species
Hymanarion hannianus
Stanisic, 2010
(by original designation); masculine.
Remarks
The gender of none of the genus names treated herein has been explicitly specified in the relevant original descriptions. However, all these names are compound words ending with the noun ‘-
arion
’, which determines the gender of these names to be masculine in correspondence with the gender of the name
Arion
Férussac, 1819. Accordingly, we here correct any previously incorrect gender assignment of species names.
The genus
Fastosarion
was originally described as a monotypic subgenus of
Helicarion
by
Iredale (1933)
, who later elevated it to full genus rank (
Iredale, 1937
). The name is of masculine gender as evident from
Iredale’s (1937)
use of the species name
F. superbus
.
Iredale (1933)
also proposed the name
Vercularion
for the
type
species
V.bullaceus
;however this name is unavailable because it was intro - duced without a description. It has not been made available subsequently by
Iredale (1937: 8)
nor
Iredale (1941: 6)
(no description). The simultaneously published name
Fastosarion
was later given precedence over
Vercularion
by First Reviewer’s choice by
Smith (1992: 231)
.
Smith (1992)
listed eight species in the genus.
Scott (1995)
revised
Fastosarion
, redescribing
F. superbus
and describing two new species,
F.helenkingae
Scott, 1995
and
F. aquavitae
Scott, 1995
.
Hyman & Ponder (2010)
moved two species to the new genus
Stanisicarion
and
Stanisic et al. (2010)
moved an additional species to
Macularion
while also describing six new species and placing two in synonymy. Subsequently, a single species was synonymized with
Mysticarion hyalinus
(Pfeiffer, 1855)
by Hyman et al. (2017), bringing the total number of accepted species in the genus to ten.
In the current study we uphold
Fastosarion
as an accepted genus, but treat the genus names
Eungarion
,
Dimidarion
and
Hymanarion
as its subjective junior synonyms.
Eungarion
was described as a monotypic genus for new species
E. mcdonaldi
, a small semislug with a very thin, flattened, reduced shell with degenerate lower whorls (
Stanisic, 1993a
).
Dimidarion
was originally introduced for four new species of small to very small semislugs from southeastern to mideastern Qld, while the monotypic
Hymanarion
was described for a small semislug found in northeastern Qld (
Stanisic et al., 2010
). Five of these six species were described based only on their shell and external appearance. These genera all have small, thin, low-spired shells of 7.5–
12 mm, but range in shape from flattened to globose. They share some anatomical characters, including a relatively short vagina, equal length arms of the epiphallus and a penis with longitudinal pilasters that often contains a proximal rounded pilaster, but other aspects of their genital anatomy differ considerably. However, all share the diagnostic morpho-anatomical characters seen in
Fastosarion
,
Stanisicarion
and
Macularion
(distinct vagina, elongate capsular gland, slender flagellum, distinct epiphallic caecum with a medial attachment of the penial retractor muscle, simple spermatophore with at most short teeth or spines) and hence we synonymise these three genera with
Fastosarion
.
We demonstrate in the current study that many
Fastosarion
species
have larger ranges than previously thought, resulting in the synonymy of several existing species. In particular, we synonymise
F.schelli
with
F.helenkingae
,
F. ameyi
with
F. aquavitae
,
F.virens
with
F. freycineti
, and
F. slatyeri
and
F. peterbrocki
with
F. alyssa
. We also introduce eight new species, bringing the total number of accepted species in this genus to 21.
The genus as delineated herein comprises Clades A and B in the mtDNA phylogeny (figs. 1–3).
Differential diagnosis
External appearance
: Shell small to large (
6–25 mm
), amber, glossy, ear-shaped, 2.6–4.1 whorls, globose to flattened with an expanded last whorl, whorls rounded. Protoconch and teleoconch with very fine spiral grooves, sometimes becoming obsolete on the teleoconch. Body colour ranging from cream to dark reddish grey or brown, dark green or black, sometimes speckled or spotted, sole often contrasting in colour and sometimes with vertical stripes. Mantle lobes and shell lappets well-developed, completely covering shell when extended, often speckled, spotted or mottled, either smooth or sculptured with pustules or ridges, sometimes with rows of larger warts on shell lappets; median and left lobes always fused to form a cephalic shield. Slime network well developed; tail sometimes keeled. Caudal horn small to prominent.
Genital anatomy
: Spermoviduct of 2–6 lobes, embedded in digestive gland. Talon and carrefour embedded in albumen gland. Spermoviduct folded several times in zig-zag fashion. Free oviduct with a large, oval, orange capsular gland medially; free oviduct internally smooth or sculptured with longitudinal pilasters or very fine transverse ridges. Vagina short to moderately long, sometimes swollen, internally smooth or with longitudinal pilasters. Bursa copulatrix short to moderately long, with slender duct and oval to elongate sac, inserted on the vagina, base of duct sometimes swollen. Penis long, cylindrical or proximally swollen, with variable internal sculpture of pustules or ridges (transverse, longitudinal or diagonal); longitudinal and/or rounded pilasters sometimes present. Penis tunica attached by muscle fibres to middle of epiphallus; epiphallus enters penis through simple pore or verge, verge never fused to penial wall; epiphallus 2 longer than or equal in length to epiphallus 1; epiphallic caecum present, penial retractor muscle attached to middle of caecum (near base). Long, slender epiphallic flagellum with axial filaxment present; internal cryptae minor and not visible externally. Spermatophore a soft-walled capsule with hard tail-pipe; tail-pipe mostly smooth, towards terminal end sometimes sculptured a single ridge with or without small teeth; spermatophore tip simple, or with hair-like spines, or expanded into a bell.