Progradungula barringtonensis Michalik & Smith, 2024

Michalik, Peter, Smith, Helen M., Milledge, Graham & Harms, Danilo, 2024, Another ghost of Gondwana-Progradungula barringtonensis Michalik & Smith, sp. nov., a new species of the relict spider genus Progradungula (Araneae: Gradungulidae) from a temperate rainforest in eastern Australia, Austral Entomology 63 (1), pp. 72-81 : 75-79

Progradungula barringtonensis Michalik & Smith , sp. nov.

https://zoobank.org/ urn:lsid:zoobank.org:act:A0674A9B-7BAE-4DE7-A900-FFEA978A7E7E

Material examined

Holotype

♂ ‘ Australia: New South Wales, Barrington Tops National Park , 14-November-2019, leg. Peter Michalik & Helen Smith’; ‘ Databased KS.129955 AMS’; ‘ Holotype: Progradungula barringtonensis Michalik & Smith’ ( AMS).

Other material examined

One immature with same data as the type ( ZMH-A0010454 ) . One immature, locality as holotype, 3 March 2016, leg. Graham Milledge & Helen Smith ( AMS KS.125999) . One immature found in different part of Barrington Tops National Park (15 November 2019, leg. Peter Michalik & Helen Smith) .

The following material was examined for comparison: P. carraiensis (female holotype [ AMS KS.1583] and male [ AMS KS.6740], Carrai State Forest, New South Wales, Australia; AMS); P. otwayensis (female [ ZIMG II /28128] and male [ ZIMG II /28127], Great Otway National Park, Victoria, Australia; ZIMG).

Diagnosis

Progradungula barringtonensis is significantly larger in body size compared to both other known Progradungula species (male carapace length as proxy; P. barringtonensis 7.5, Figure 2a; P. carraiensis 5.03, Figure 4a [see Gray 1983] and P. otwayensis 5.42 [see Milledge 1997]). It is most similar to P. carraiensis by having male genitalia with a bifurcated process of the embolus (Figures 3c and 4d, but clearly differs by the size and position of the tegular median apophysis (Figures 3c and 4d; compare Gray [1983, Figures 3 and 4]). P. barringtonensis resembles P. otwayensis by having male genitalia with a similar positioned large tegular median apophysis, but clearly differs by a distally only slightly bent embolus with a bifurcated process (Figures 3c; compare Milledge (1997, Figures 1–3) and Michalik et al. [2013, Figure 5]).

Description

Based on male holotype ( AMS KS.129955; Figures 2–3).

Measurements. Carapace length 7.5; carapace width 5.1; caput width 2.7; abdomen length 7.6; abdomen width 4.6. Legs: length of segments (femur + patella/tibia + metatarsus + tarsus = total length): I: 14.2 + 17.1 + 17.3 + 3.7 = 52.3, II: 12.4 + 13.7 + 13.4 + 3.6 = 43.1, III: 10.4 + 11.5 + 11.2 + 2.6 = 35.7, IV: 12.7 + 13.5 + 12.8 + 2.7 = 41.7, palp: 4.1 + 3.7 + + 2.7 = 9.4.

General appearance. Carapace yellowish brown, darker in eye region. Chelicerae, maxillae and labium dark reddish brown. Sternum reddish brown marginally, paler centrally. Legs yellowish brown. Abdomen dark brown. Carapace longer than wide, widest between coxae II and III. Cephalic area elevated behind eyes. Fovea pit-like.

Eyes. Frontal view: anterior row straight to slightly recurved, posterior row slightly procurved. Dorsal view: anterior row slightly recurved, posterior row slightly recurved. Clypeus height 0.45. AME black, remainder white.

Chelicerae. Strong, vertical, slightly divergent.

Maxillae. Subparallel, external margin strongly curved and ending anteriorly in a bluntly pointed apex. Serrula present.

Labium. Free. Length 0.8, width 0.9. Apical margin indented, lateral margin subparallel below, sloping in towards apex above.

Sternum. Length 4.1, width 2.2. Elongate, shield-shaped with pointed apex which extends back midway between coxae IV.

Legs. 1243. Trochanters shallowly notched. Superior claws of leg I and II dissimilar, with raptorial proclaws long and strongly developed, retroclaws shorter. Inferior claws of legs I and II slender and strongly hooked. Superior claws of legs III and IV similar. Accessory claw setae on all tarsi. Distal half of tarsus I and II with strong ventral setae. Calamistrum reduced.

Abdomen. Vestigial cribellum, with very narrow spinning field, as wide as basal span of anterior spinnerets (Figure 3e,i). Anterior and posterior book lungs well separated. Spiracles of posterior lung books well separated but joined by a transverse groove.

Palp. Cymbium ventrally furrowed. Median hematodocha very prominent. Tegulum with a large spine-like median apophysis. Embolus tube-like with a solid bifurcated clawlike process; tip of the embolus widened and hyaline.

Remarks

Females unknown and immatures are not further considered for the description except for providing a barcode sequence from an immature (ZMH-A0010454, same locality as holotype) (GenBank OR687334).

Etymology

The specific epithet of the species is derived from its distribution area (Barrington Tops National Park), in accordance with the naming of the other two known Progradungula species.

Distribution

This species is likely endemic to patches of old Nothofagus forest in the higher sections of Barrington Tops National Park (NSW, Australia) where all specimens were collected from old hollow trees. Specimens have previously also been seen in ground-level cavities caused by dislodged roots of fallen trees and similar secure and dark retreats. The authors were not able to locate specimens in eucalypt forests surrounding the Nothofagus , nor in younger regrowth Nothofagus stands, suggesting a rather limited distribution for this species.

Biology

The webs P. barringtonensis are similar to those described for the other two Progradungula species ( Gray 1983; Ramirez & Michalik 2019), featuring a sturdy signal line leading to an upper scaffold, which is connected via suspensor lines to the catching web composed of cribellate silk. Field observations have shown that the catching ladder typically has an average of eight looping segments, similar to P. otwayensis ( Ramirez & Michalik 2019) , although an immature specimen in captivity constructed catching ladders with more looping segments, similar to P. carraiensis with estimated 14–25 segments ( Forster & Gray 1979; Gray 1983) (Figure 5).