Lophoturus boondallus, Huynh, Cuong & Veenstra, Anneke A., 2018

Huynh, Cuong & Veenstra, Anneke A., 2018, Two new Lophoturus species (Diplopoda, Polyxenida, Lophoproctidae) from Queensland, Australia, ZooKeys 741, pp. 133-154 : 136-140

Lophoturus boondallus sp. n.

Holotype.

Adult male, stadium VIII - 13 leg pairs stage, collected from Boondall Wetlands Park, Boondall, Brisbane, Queensland; 27°20'25.85"S, 153°4'36.94"E, elevation 9 m. The species was collected from leaf litter near the main entrance of the park on 10 November 2015 by author (CH).

Paratypes.

One male and 9 females were collected in the same location and date as holotype. (1 male and 2 females were used for SEM imaging in this study).

Etymology.

The species is named Lophoturus boondallus sp. n. as they were first found in Boondall Wetlands Park, Boondall, Queensland, Australia.

Diagnosis.

L. boondallus has the following morphological characteristics: 3 sensilla on the 6th antennal article and labrum with two linguiform processes. These features are typical characteristics of Lophoturus . Live specimens from this species are light or ange in colour with a round arc-shaped body form in cross section. Adults body length range from 1.6-2.2 mm.

Description.

Measurements: Holotype male body length 1.9 mm, females (paratypes) (n = 8) range from 1.9-2.2 mm. Caudal bundle of the male is slightly narrower in width with 0.6 mm in length than that of the female (0.5 mm) (Fig. 6 A–B)

Colouration. Head light orange and dark reddish-brown laterally; body light orange, contrasting with their white pleural trichomes and lighter coloured caudal bundle (Figure 2B).

Head. Ommatidia absent. Vertex with two posterior trichome groups, a large gap presents between them. Each group consists of 2 rows, the anterior, oblique row has similar sized trichome sockets. Posterior row has fewer trichome sockets with a narrow space between the anterior and posterior rows. Holotype male has 12 + 12 trichome sockets in anterior rows and 4 + 4 trichome sockets in posterior rows (Fig. 3A); paratypes indicate that variation is common in this species, ranging from 12-15 (anterior rows) and 3-7 (posterior rows) (Fig. 6C). Trichobothria: trichobothrium a, located in posterior position with a medium socket; trichobothrium b, lateral position with largest socket; and trichobothrium c, anterior position with smallest socket. Trichobothria a and b have typically thin sensory hairs with narrow cylindrical funicles compared to trichobothrium c, with a claviform funicle. Trichobothrium sockets (a, b and c) arranged unevenly between ab and bc, as trichobothria a and c located more inward (Figs 3E, 6D).

Antennae. 8 articles (4 tiny, reduced sensory cones), 7th and 8th antennal articles are equal in length (Fig. 4A), which is characteristic of Lophoproctidae . The 6th antennal article has 3 thick bacilliform sensilla (T) of differing lengths: medium sensillum posteriorly (Tp); the longest and thicker intermediate sensillum (Ti); a short sensillum anteriorly (Ta) with its socket located distally; and a conical sensillum posteriorly (c) (Figs 4C, 6F). The 7th antennal article has 2 thick bacilliform sensilla (T), the anterior Ta shorter than Tp located posteriorly, with one setiform sensillum (s) between them plus a conical sensillum (c) located in the posterior position (Figs 4B, 6E). This pattern of sensilla on the 7th article is common to all Lophoturus species.

Clypeo-labrum: Holotype has 10 setae, all half the width of the labrum. Setae on paratypes ranged from 10-12. Labrum surface setose, with tiny, backward facing hairs. Anterior margin of labrum with two whole lamellae, and a linguiform process present on each side of median cleft of labrum (Figs 3H, 7A).

Gnathochilaria. Medial palps only, 58 sensilla on the palp of holotype (male) and 18-22 sensilla on paratypes (females) (Fig. 3 F–G).

Trunk. Comprised of 10 segments, 9 pleural projections, excluding the telson and caudal bundle; 13 pairs of legs. Collum - tergite 1 (smallest tergite) with trichome sockets arranged in 2 oval shapes laterally, connected by posterior curved rows of trichome sockets with a large gap in the middle. The collum is the only tergite with lateral protuberances bearing a small number of trichome sockets. In holotype, the collum has 52 (Left: L), 52 (Right: R) trichome sockets and the lateral protuberances with 7 trichome sockets on each side (Fig. 3B). Numbers varied in paratype females within a range of 46-58 trichome sockets in the collum and the number of lateral protuberances trichome sockets range 6-8. Tergites 2 to 10, have a pair of pleural projections located antero-laterally. The arrangement of tergal trichome sockets from tergites 2 to 10 typically have 2 latero-posterior oval groups with a few sockets extended on both ends with these groups separated by a large medial gap. Trichome sockets of tergite 2 in the holotype has 54 (L) and 54 (R) (Figs 3C, 6C), tergite 10 has 38 on both sides (Fig. 3D). In contrast, the trichome sockets of tergite 2 in paratypes ranged 54-66 and tergite 10 ranged 34-46 trichome sockets.

Legs. Leg segments are named following Manton (1956). Legs 1 and 2 without trochanter, leg 1 also lacks tarsus 1. Chaetotaxy as follows: coxa 1: 2 pubescent oval setae, coxa 2: 3 pubescent oval setae, coxae 3-13: 0-4 pubescent oval setae; pre-femur, femur and post-femur with 1 pubescent oval seta (Fig. 5 A–B), tarsus 2 with a spine (Fig. 5C). Posterior edge of last sternite has 0-4 pubescent oval setae similar to those present on the coxa and the number of these pubescent oval setae varies: 2 on the holotype and 0-4 on the paratypes. Sex organs in male: A pair of penes on the 2nd coxa and coxal glands absent.

Telotarsus–Claw. slender with two latero-dorsal denticles (ldd) equal in length, a basal denticle (bd) and a small denticle (smd) present near the tip of the claw (Figs 5D, 7B).

Telson. Dorsal ornamental trichome sockets symmetrically arranged on each side, with 6 sockets of trichome a in the holotype; paratype females have 6-8 sockets of trichome a, a single trichome b and two large protruding base sockets of trichome c: c1 and c3 (The absence of c2 is characteristic of lophoproctid species) (Fig. 5E).

Caudal bundles. In the holotype male, the caudal bundle is formed by a single group of trichome sockets of uniform sizes; this structure is split ventrally with trichome socket-free tissue present and extending with a small gap dorsally toward the centre. 3 rows of the largest size barbate trichome sockets present, forming slightly uneven lateral rows that extend toward the centre of the caudal structure (Fig. 7C). In paratype females, the caudal bundle structure differed from the male, with two distinguishing structures apparent: the main dorsal structure, was similar to the male, and 2 latero-sternal structures with finer nest trichome sockets. These finer sockets located on the interior and were surrounded by 2 rows of caudal trichome sockets on exterior surface. A trichome socket-free area is present ventrally, extending with a small gap and connecting with central bare tissue with few barbate trichome sockets present. Caudal and nest trichome sockets are clearly separated. These structures gradually form a single caudal bundle structure (Fig. 7D). The structure of L. boondallus caudal bundles and their caudal trichomes is similar to those of Monographis ( Polyxenidae ) ( Huynh and Veenstra 2013, 2015) and classified as Type II by Condé and Nguyen Duy-Jacquemin (2008).

Remarks.

L. boondallus differs from L. queenslandicus in being shorter in length, in having light orange colouration, a round arc-shaped body form when viewed in cross section. Furthermore, it also differs genetically from the other Lophoturus species. In contrast, L. queenslandicus is rusty brown with a yellowish light green median band dorsally and two darker brown strips laterally; body 2.4-2.8 mm long, with a flattened arc shape (Fig. 2).