Alpheus bunburius Banner & Banner, 1982

Anker, Arthur, 2023, Revision of Alpheus euphrosyne De Man, 1897 and A. microrhynchus De Man, 1897, with description of three new species and taxonomic remarks on several other morphologically and ecologically similar snapping shrimps (Malacostraca: Decapoda: Alpheidae), Zootaxa 5282 (1), pp. 1-115 : 85-86

Alpheus bunburius Banner & Banner, 1982

( Fig. 46A–D , Fig. 52D )

Alpheus bunburius Banner & Banner 1982: 213 , fig. 66.

Type material. Holotype: ov. female (cl 13.7 mm, tl 38.0 mm, chl 13.5 mm), WAM 271-65 , Australia, Western Australia, Bunbury, leg. W.H. Butler, 03.1962.

Description. See Banner & Banner (1982) for detailed description and illustrations; see also Fig. 46A–D and remarks below.

Colour pattern. Unknown.

Type locality. Bunbury , Western Australia .

Distribution. Southeastern Indian Ocean: presently known only from the type locality in Western Australia ( Fig. 52D ).

Common name proposed. Bunbury snapping shrimp.

Ecology and biology. The general ecology and biology of A. bunburius remain largely unknown (but see below). The presence of numerous small eggs (diameter ~1.0 mm) in the female holotype indicates an extended larval development.

Taxonomic remarks. Alpheus bunburius was described on the basis of a single female specimen from Bunbury, Western Australia, without any biological or ecological information.According to Banner & Banner (1982), the form of this species [ A. bunburius ] is very similar to A. euphrosyne euphrosyne De Man and A. euphrosyne richardsoni Yaldwyn, but in addition to the differences in the palmar/finger length this species differs in the low dactylar plunger of the dactylus of the large chela and the trigonal dactylus of the third pereiopod. However, the rather unusual proportions and small size (relative to the body) of the major cheliped of the holotype of A. bunburius suggest that this appendage may be a former minor cheliped in the process of transformation into a major cheliped. This type of regeneration, i.e., transformation of a major cheliped into a minor cheliped, is not uncommon in Alpheus , often after a loss (autotomy or injury) of the original major cheliped (A. Anker, pers. obs.; see also Shin-Ike 1956; Read & Govind 1998 and references therein). In most morphological characters, except for the afore-mentioned trigonal dactylus, A. bunburius is identical to the female specimens of A. richardsoni .

Bunbury, the type locality of A. bunburius , is a small town with two large rivers and an extensive saltwater lagoon connected to the open ocean by a large breach; mangroves are present in the estuary of at least one of the rivers, in Vittoria Bay. According to Banner & Banner (1982), A. richardsoni occurs in “large brackish rivers systems in Bunbury and Perth in Western Australia ”. On the other hand, A. bunburius has never been reported since its original description, which is somewhat surprising for a relatively well-sampled area. This fact, combined with the aberrant condition of the major cheliped in the holotype of A. bunburius and the great general similarity between A. bunburius and A. richardsoni , suggest that A. bunburius could also be a junior synonym of A. richardsoni . However, a side-by-side comparison of the third pereiopods of the holotype of A. bunburius and a female specimen of A. richardsoni from New South Wales revealed some differences in the shape and relative length of the dactylus ( Fig. 46 ). In A. bunburius , the third pereiopod dactylus is feebly expanded, trigonal-conical in cross-section, and about 0.4 length of the propodus ( Fig. 46A–D ; see also Banner & Banner 1982: fig. 66i). In contrast, in A. richardsoni , the third pereiopod dactylus is more expanded, spatulate, and almost 0.5 length of the propodus ( Fig. 46E–G ; see also Banner & Banner 1982: fig. 74n). Based on this difference, A. bunburius is herein tentatively maintained as a valid species, i.e., distinct from A. richardsoni . Nevertheless, it remains a problematic taxon, being based on a single female specimen, possibly with a regenerated major cheliped, and without any information on the species’ habitat and colour pattern. It is possible that A. bunburius represents a unique western Australian transitional freshwater—brackish water form derived from A. richardsoni , like A. microrhynchus is in South-East Asia, deriving from mangrove forms, such as A. eurydactylus or A. takla sp. nov. A more intensive sampling of estuarine snapping shrimps in Bunbury and Perth areas will hopefully result in the collection of additional male and female specimens of A. bunburius , which would then allow a full redescription of the species and clarify its ecology and phylogenetic affinities.

Figures

FIGURE 46. Alpheus bunburius Banner & Banner, 1982: holotype, female (cl 13.7 mm) from Bunbury, Western Australia (WAM 271-65) [A–D]; A—third pereiopod, lateral view; B—same, propodus and dactylus, lateral view; C, D—same, dactylus in mesial [C] and dorsal [D] views (simple setae omitted in B–D). Alpheus richardsoni Yaldwyn, 1971: female (cl 9.5 mm) from Gold Coast, Queensland, Australia (OUMNH.ZC. 2009.09.16) [E–G]; E—third pereiopod, lateral view; F—same, distal part of propodus and dactylus, lateral view; G—same, dactylus, dorsal view (simple setae omitted in F, G).

FIGURE 52. Distributional maps for species of Alpheus treated in this study:A—A. takla sp. nov.; B—A. mangalis sp. nov. and A. cf. mangalis sp. nov.; C—A. songkla Banner & Banner, 1966 and A. cf. songkla (see text); D—A. paludicola Kemp, 1915, A. nipa Banner & Banner, 1985 and A. bunburius Banner & Banner, 1982; E—A. pontederiae de Rochebrune, 1883; F—A. firmus Kim & Abele, 1988 and A. cf. firmus (see text).