Pharaxonotha taylori Skelley and Tang

Tang, William, Skelley, Paul E., Taylor B, Alberto S. & Salzman, Shayla, 2024, Review of Pharaxonotha Reitter (Coleoptera: Erotylidae: Pharaxonothinae) inhabiting cones of the cycad Zamia L. (Cycadales) in Panama, with descriptions of five new species, Insecta Mundi 2024 (43), pp. 1-40 : 31-33

Pharaxonotha taylori Skelley and Tang

Figures 11A–J (photographs 1A–J in Skelley and Tang 2020)

Pharaxonotha taylori Skelley and Tang 2020: 4–7 .

Diagnosis. Pharaxonotha taylori is the smallest known member of the genus, length 1.59–2.08 mm. Other distinguishing characters include the pale brown body coloration; pronotum with basal lateral sulcus of disc indistinct to absent; pronotal hind angles and humerus of elytra rounded, lacking small denticle; narrowed protibia with straight apical margin bearing complete row of short stout spinules; male terminalia not distinctly dorsoventrally flattened; and known distribution in Panama on Zamia cunaria and Z. ipetiensis .

Description. [Reprinted with minor changes from Skelley and Tang (2020)]. Type series length 1.59–2.08 mm, width 0.60–0.81 mm. Body ( Fig. 11A–C ) in dorsal view elongate, somewhat cylindrical, greatest width at middle of elytra; in lateral view weakly convex dorsally. General body color entirely pale yellow-brown; dorsal surface punctate, weakly alutaceous, shining and appearing glabrous, short procumbent hairs associated with punctation on pronotum and elytra, ventrally shining and appearing glabrous except mesoventrite and abdomen with short sparse procumbent setae.

Head not broad ( Fig. 11D–E ), width = 0.78–0.84× pronotal width; in dorsal view conical, gradually narrowed anteriorly, surface flat to slightly convex, finely, moderately punctured, average distance between closest punctures 3–4× width of puncture; head width 0.40–0.51 mm; dorsal interocular distance 0.23–0.29 mm, head width/dorsal interocular distance ratio 1.55–1.91, ventral interocular distance 0.14–0.21 mm, head width/ventral interocular distance ratio 2.37–2.86. Eye with large black facets, about 2× diameter of head punctures. Antennal length slightly shorter than pronotal width, 1.2× head width; antennomere I (scape) fairly large, slightly elongate; antennomere II slightly larger than III; IV circular; IV–VIII small, equal in length, VII–VIII becoming slightly wider with flattened apex; club fairly large, IX and X similar in length; XI not enlarged, slightly longer than X, globular with rounded apex. Clypeus weakly concave anteriorly, moderately punctate. Transverse occipital line [vertexal line] distinct from eye to eye. Mentum and submentum coarsely punctured, distance between nearest punctures approximately 2–3× own diameter, each puncture with a short seta; submentum with weak medial depression visible on some. Gular area smooth, without punctation or setae, border with submentum marked by change in punctuation and with a shallow transverse depression.

Thorax with pronotum transversely quadrate in dorsal view, length/width ratio 0.71–0.81; with distinct marginal carina laterally and basally, anteriorly with fine marginal carina medially; surface mostly convex, slightly flattened medially; anterior angles broadly rounded, not projecting forward; posterior angles rounded, lacking small denticle at angle; lateral margin evenly shallowly arcuate medially, more strongly anteriorly and posteriorly; posterior margin slightly projecting medially, projection beginning approximately by pair of small, dark pores in margin located 1/4 width from posterior angles, each pore marks base place where an indistinct sulcus may extend anteriorly onto disc at most 1/8 length of pronotum, sulcus usually lacking. Prosternum in ventral view convex, with few scattered punctures; anterior margin slightly emarginate, finely denticulate with row of long, anteriorly directed setae, longest setae approximately 1/3 length of eye; prosternal process convex apically, expanded and truncate at apex. Hypomeron laterally with few minute punctures, medially lacking distinct longitudinal striations. Scutellar shield distinctly transverse pentagonal, posterior margin weakly rounded. Elytra in dorsal view elongate, convex; length/width 1.66–1.87, greatest width near midlength; with distinct marginal line basally; 10 complete striae of moderate puncture size; scutellary striole extending 1/4 elytral length, with 10–15 punctures; punctures of elytral striae slightly larger than pronotal punctures, striae not impressed; intervals of striae with fine, shallow punctures, 1/2 size of strial punctures; all punctures of elytral bearing a single short seta; seta only visible in profile, extending slightly out of puncture. Mesoventrite with fine indistinct punctuation. Metaventrite glossy, with weak lateral punctation separated by 4–5× own diameter; medial surface indistinctly punctured; entire surface convex, metathoracic discrimen extending approximately 3/4 metaventrite length. Legs narrow, relatively similar in length and shape. Procoxa oval; mesocoxa globular; metacoxa transversely elongate-oval; trochanters obliquely truncate apically; femora weakly robust, moderately compressed laterally; tibiae shorter than femora, weakly widening to truncate apices; protibia with apical lateral tooth weak, with complete apical fringe of short spinules on straight ventral apical margin; meso- and metatibia with apical fringe of short spinules on anterior margin, finer setae on posterior margins.

Abdomen. Ventrite apical margin bearing short, sparse setae; all ventrites finely, sparsely punctate across surface, distance to nearest puncture approximately 4–5× diameter of puncture, punctures bearing mostly reclining setae; ventrite V with setae length nearly uniformly approximately 2× diameter of puncture; I–IV each with 2 or more median pairs of longer, semi-erect sensory hairs (difficult to see in poor lighting, often abraded). Male genitalia (n = 6) not distinctly dorsoventrally flattened, tegmen parallel-sided in dorsal view, parameres in dorsal view with asymmetrical apices; elongate cylindrical median lobe, and long coiled flagellum ( Fig. 11F–H ).

Female. Similar to male, no sexual dimorphism observed. Genital tube elongate, length past abdominal segment VIII = 4× width (n = 6); gonostylus set apically on gonocoxite, gonostylus length = 4–5× width ( Fig. 11I ). Spermatheca C-shaped, length> 4× width, basal third smooth, slightly swollen and wider than apical third, apex annulated ( Fig. 11J ).

Range. Known from eastern Panama in male cones of Zamia cunaria and Z. ipetiensis .

Materials examined. There are 62 specimens of the type series of P. taylori as reported by Skelley and Tang (2020): PANAMA: Panamá Province, Llano Carti, 300-400 m asl, Nov-18-2000 or Sept-8,23-2004, A. Taylor, Vial #15, Zamia cunaria , wet, lowland tropical forest, 300 m asl (holotype, allotype, 14); same locality, Sept-2- 2003, A. Taylor, #25, Zamia ipetiensis in population of Z. cunaria , wet, lowland tropical forest (11); same locality, 300-400 m asl, Sept-2-2003, A. Taylor, #5; Zamia ipetiensis in population of Z. cunaria , wet, lowland tropical forest (9); same locality, ♂ bait cone Zamia ipetiensis ( Z. cunaria habitat), 26-VIII-2011, A. Taylor (21); same province, Ipeti-Emberá, 200 m asl, Nov-18-2000 or August 12-2001, A. Taylor, Vial #21, Zamia ipetiensis , wet, lowland tropical forest (6). Repositories are reported in Skelley and Tang (2020). In Tang et al. (2020), these are presented on their tree as “D0063 Z. cunaria > PANAMA ”.

Additional specimens studied but not included in type series. COLOMBIA: Chocó, near Quibdó, III-2009, M. Colonje, Zamia pyrophylla ♂ cones (4 FSCA). In Tang et al. (2020), this population is presented on their tree as “D0021 Z. pyrophylla > COLOMBIA”.

Remarks. The two recognized hosts of P. taylori , Zamia cunaria and Z. ipetiensis , occur within the same province of Panamá. Morphologically, these Zamia are separated by small differences in leaflet and cone characters ( Stevenson 1993) and a phylogenetic analysis of the genus Zamia , based on 10 genes and encompassing the majority of recognized species in the genus ( Calonje et al. 2019), indicate these two host species are closely related, although not identical. A preliminary cross-pollination experiment ( Taylor and Calonje 2015) using hand-pollination techniques suggests that some genetic reproductive barriers may exist between the two host species, however, the fact that Pharaxonotha beetles in Z. cunaria habitat are readily attracted to Z. ipetiensis bait cones ( Terry et al. 2012), reveals no reproductive barriers by the hosts to the beetles that inhabit their cones. Based on the information available the beetles from these two host Zamia were treated by Skelley and Tang (2020) as a single species. Beetles collected on cones of Z. pyrophylla , a host that is restricted to Colombia, are morphologically similar, but tend toward a larger size range (body length = 1.98–2.07 mm, n = 4; vs. 1.67–2.08 mm) and exhibit some genetic difference with those from the Z. cunaria habitat ( Tang et al. 2018b, 2020). Although morphological and genetic analyses indicate that Z. pyrophylla belongs within the same host species group as Z. cunaria and Z. ipetiensis ( Calonje et al. 2010, 2019), its habitat is separated by some 400 km from the latter two species. These Colombian beetles are treated as a potentially separate species from P. taylori and were exclude them from the type series ( Skelley and Tang 2020). No Notorhopalotria weevils have been detected to co-occur with P. taylori and this Pharaxonotha is currently considered to be the sole pollinator in its hosts.

Kirschii species group

Adult diagnosis. The kirschii species group can be distinguished from other Pharaxonotha by a more robust head that has a temple behind the eye, and male with a small tooth or denticle at apex of terminal abdominal ventrite. Remarks. This species group was established by Skelley et al. (2022) based on analysis of the 16S rRNA gene of two populations that are part of the early diverging lineages in Tang et al. (2018b, 2020). Although no representatives of this group were detected on Zamia in Panama during this study, members of this group have been collected from cones of Ceratozamia , Dioon and Zamia in Mexico and P. kirschii is known to occur in Panama (see Skelley et al. 2022 and Materials examined under P. kirschii below). Members of this group likely represent a complex of species. Further work is needed on both the cycad associated and the free-living populations.

Figures

Figure 11. Pharaxonotha taylori. A–C) Dorsal, lateral and ventral habitus. D–E) Head, dorsal and ventral views. F) Genital capsule and tegmen attached to median lobe, (top to bottom) ventral and lateral views. G) Tegmen attached to median lobe, (top to bottom) ventral and lateral views. H) Male genital capsule. I) Retracted ovipositor, ventral view. J) Spermatheca. Images F–J reproduced from Skelley and Tang (2020).