Aphanocephalus potamophilus Lea 1921
Creators: name: Szawaryn, Karol
Publisher: name: Zenodo
Year: 2025
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Coleoptera
Discolomatidae
Aphanocephalus
Aphanocephalus potamophilus

description: Aphanocephalus potamophilus Lea, 1921a
(Figs 9A, B, 13D–F, 15E)
Aphanocephalus potamophilus Lea, 1921a: 369.
Aphanocephalus potamophilus John, 1954: 304 — John 1959: 35; John 1967a: 113. Junior homonym. New synonym.
Material examined. Type material.
Lectotype and paralectotypes (here designated). WESTERN AUSTRALIA: " potamophilus Lea, TYPE Upper OrdR / 6933 Aphanocephalus potamophilus Lea N. W. Australia [black ink, handwritten] TYPE [red ink, handwritten]/ SAMA Database No. 25-036254 " (SAMA) (Fig. 6A). Four specimens are mounted on a single card, the second specimen from the left with “TY” handwritten beneath it, is here designated as the lectotype, the remaining three specimens are paralectotypes. Paralectotypes. WESTERN AUSTRALIA: " upper Ord R., E. Kimberley, Helms / Co-type/ also slide/ I.12031 Aphanocephalus potamophilus Lea N. W. Australia [black ink, handwritten] TYPE [red ink, handwritten]/ SAMA Database 25-50369 " (5, SAMA); "Water edge/ CO-TYPE/ Co-type/ Upper Ord R/ C/2266/ Aphanocephalus potamophilus Lea N. W. Australia [black ink, handwritten] Cotype [red ink, handwritten]" (2, QMB); " Upper Ord R/ Aphanocephalus potamophilus Lea, co-type/ SYNTYPE T.13455 Aphanocephalus potamophilus Lea, 1921 [red rectangle]/ [blue rectangle] " (1, MMV).
Types of A. potamophilus John. Lectotype and paralectotype (here designated). WESTERN AUSTRALIA: " Upper Ord R/ Australia 1921-94./ Aphanocephalus potamophilus Lea, Co-type/ Aphanocephalus potamophilus John, det. H. John / Typus [red rectangle]" (NHM). Two specimens mounted on the same card with ♀ and ♂ symbols beneath, the right specimen (male) is here designated as the lectotype. The female is a paralectotype.
Other material. WESTERN AUSTRALIA: "Co-type/ Upper Ord R / C/2339 / Aphanocephalus bimaculatus Lea N. W. Australia [black ink, handwritten] Cotype [red ink, handwritten]" (2, QMB); Upr. Ord. R., E. Kimberley Helms/ Aphanocephalus potamophilus Lea id. W. Armstrong (2, ANIC). These specimens look exactly as A. potamophilus also the locality is identical to the holotype locality, so the label with the species name is definitely a mistake; these specimens probably are a part of the original type series of A. potamophilus. QUEENSLAND: Station CK. 11m. N. Mt. Molloy. N.Q. 18-II-69. J.G. Brooks Q. 691./ J.G. Brooks Bequest, 1976 (5, ANIC); Station CK. N.Q. 18-II-69. J.G. Brooks/ Q. 691./ J.G. Brooks Bequest, 1976 (4, ANIC); QLD, 2km W of Chillagoe 330m. 28/6/71 Decid. Vine. Thicket/ BerlesateANIC, 341 Taylor Feehan 17.14x144.30 (3, ANIC).
Type locality. Western Australia, Upper Ord River.
Distribution. Northern Queensland, Western Australia (Fig. 16).
Diagnosis. Species quite variable in coloration. Rufous specimens of A. potamophilus are most similar to A. calderi sp. nov. in body coloration. However, it can be distinguished from the latter by distinct lateral margins of the elytra, whereas in A. calderi, they are very narrowly explanate. Moreover, A. potamophilus has double-sized punctae on the pronotum, with larger and coarser punctae in the posterior pronotal corners, while in A. calderi, the punctation is single-sized. The central area of the elytra in A. potamophilus are covered with two intermixed sizes of punctae, while in A. calderi it is covered with small punctae of a single size. The male genitalia of A. potamophilus are also most similar to those of A. calderi, but the apex of the tegmen is truncate in A. potamophilus (Fig. 13F) and rounded in the latter (Fig. 10I). In lateral view, the penis of A. potamophilus has a less distinctly rounded inner margin (Fig. 13D) than in A. calderi (Fig. 10G). Dark specimens of A. potamopilus may also be similar to A. slipinskii sp. nov., both species can potentially overlap in mid Queensland. Then dissection of male genitalia is necessary, in A. potamopilus tegmen is more elongate and slightly narrowing towards truncate apex (Fig. 13F), while in A. slipinskii sp. nov. tegmen is much shorter, stout, with sides regularly rounded and apex broadly rounded (Fig. 14F). In A. potamophilus penis in lateral view has less roundly produced inner margin (Fig. 13D), while in A. slipinskii it is distinctly rounded (Fig. 14D); also, outer margin of gonopore is slightly hooked in A. potamophilus, while in A. slipinskii it is straight.
Redescription. Length: 1.84–1.93 mm, width: 1.35–1.46 mm. Body elongate oval about 1.30–1.35 times as long as wide, moderately convex in lateral view (Figs 1B, 6A, 9A, B). Pronotum and elytra covered with yellowish, moderately long setae, more densely distributed on pronotum than elytra. Pronotum and elytra rufous to light brown with just sutural line on elytra and lateral margins of elytra narrowly dark brown (Fig. 9A), sometimes central part of pronotum darkened, and dark brown sutural line on elytra extends laterally into rhomboid macula, sometimes covering the whole central area of elytra (Fig. 6A); ventral side light brown to yellow; antennae, mouthparts and legs yellow. Sometimes entire pronotum and elytra light brown without darkened areas.
Pronotum covered with punctae of two sizes, disc, lateral and anterior part with small punctae, only posterior corners with coarser punctae. Lateral margins of pronotum bordered, anterior margin without bordering line. Elytra covered with punctae of two sizes, uniformly intermixed. Pronotum and elytra distinctly explanate laterally, margins well visible throughout. Lateral sides of elytra slightly rounded, without pseudopores. Epipleuron with shallow sub-marginal furrow.
Mentum without lateral carinae. Labial palps narrowly separated. Prosternum with notosternal carinae well visible; prosternal process with lateral carinae absent. Metaventrite about same length as ventrite 1. Ventrite 1 longer than ventrites 2–4 combined. Ventrite 1 with large punctae covering almost entire surface except posterior part of central area, which is covered with much smaller punctae; ventrites 2–5 covered with punctae of two sizes, coarser in lateral areas and at base of ventrite forming a single row, and smaller on the rest of surface.
Male genitalia. Tegmen in inner view with sides rounded in middle, slightly tapering toward apex in apical part, apically broadly truncate, with a few short setae at apex (Fig. 13F); in lateral view broad at base, sub-triangular in apical part, pointed at apex, outer margin slightly rounded, inner margin sinusoidal in middle (Fig. 13E). Penis long, broadening toward apex, outer margin straight in basal 3/4 and roundly curved in apical fourth, inner margin apically sinuate; gonopore about as long as wide, with apex slightly extending beyond apex of penis, apically truncate; outer margin of gonopore with blunt hook (Fig. 13D).
Female genitalia. Coxites narrow, elongate. Sperm duct diverging apically from bursa copulatrix; spermatheca with vermiform basal part and bulbous apical part (Fig. 15E), apical part about same diameter as basal part.
Remarks. Lea (1921a) described A. potamophilus from North Western Australia without designating a holotype. Four specimens, mounted on a single card with the label "TYPE" are deposited in the SAMA collection. The second specimen from the left, with the handwritten "TY" beneath it, is here designated as the lectotype to fix the taxonomic status of this species. The remaining three specimens are paralectotypes.
In his publication Lea (1921a) mentioned that this species was collected near water edges.
After describing the species, Lea sent co-types of his newly described species to the British Museum in London. Three decades later, John examined these specimens, but unaware of Lea’s description, he described his species under the same name (using the original name from Lea's label) based on the same specimens. Thus, John's species is both a homonym and a synonym of A. potamophilus Lea. John examined two of Lea’s specimens preserved in the NHM, mounted on a single card: the left specimen is a female, and the right is a male. John did not designate a holotype for his species, but he dissected the male genitalia. Therefore, the male specimen is here designated as the lectotype to fix the taxonomic status of this species.
Later John (1959) mentioned that A. potamophilus occurs on the Lord Howe and Norfolk Islands, however, no such specimens were found, so this information needs verification.
description: Published as part of Szawaryn, Karol, 2025, Revision of the Australian species of Aphanocephalus Wollaston (Coleoptera: Discolomatidae), pp. 401-440 in Zootaxa 5632 (3) on pages 429-431, DOI: 10.11646/zootaxa.5632.3.1, http://zenodo.org/record/15372416