Rhombonotus gracilis

Graceful Ant Mimic at Melba, ACT

Rhombonotus gracilis at Melba, ACT - 31 Jan 2012
Rhombonotus gracilis at Melba, ACT - 31 Jan 2012
Rhombonotus gracilis at Melba, ACT - 31 Jan 2012
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Identification history

Rhombonotus gracilis 3 Jan 2023 Bron
Rhombonotus gracilis 1 Oct 2022 YumiCallaway
Judalana lutea 6 Jun 2020 MichaelMulvaney
Unidentified 29 Apr 2020 Bron

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User's notes

Judalana lutea?

12 comments

YumiCallaway wrote:
   8 May 2020
I haven't looked into it much yet, but I would suggest one of the 4 (I think?) ant mimic genus or if not, a genus like Domoetas. These are the only ones I can think of off the top of my head with this distinctive body shape.
CathB wrote:
   9 May 2020
What about Rhombonotus gracilis?
   9 May 2020
I think it is to large to be Rhombonotus gracilis which get up to 3mm
YumiCallaway wrote:
   9 May 2020
I've looked through photos Whyte & Anderson's guide (2017) and arachne.org and have come up with this list:
Not Poecilipta sp (lack of speckled head)
Not Bianor sp (very different abdomen shape)
Perhaps Damoetas sp (potentially too small)
Not Holoplatys sp (It's quite convex; it's not flat)
Perhaps Judalana sp (potentially too small)
Perhaps Ligonipes sp (difficult to tell if the brushes of hair are present on leg 1, however I think this is likely)
Not Myrmarachne sp (leg 1 is not enlarged)
Not Rhombonotus sp (too small - it's small size is specifically stated)
Not Amyciaea sp (very different)
Maybe this will help!
YumiCallaway wrote:
   9 May 2020
Also, Bron, do you remember if the first pair of legs were fringed? This might help point out genus.
Bron wrote:
   9 May 2020
When I took the photo, Judalana lutea was suggested by the owner of the Amateur Entomology Australia site. I think the front legs were hairy? Yumi although I'm not sure (8 yeas ago) and my photographic skills on a small subject were pretty poor. Thanks for looking so hard for the id :) IT's not Holoplatys sp. The tags I have on this photo suggested Ligonipes sp.
YumiCallaway wrote:
   10 May 2020
Thanks Bron! I've taken a closer look today think J. lutea is most likely. 1. Fringes of hair on the tibia suggest Jodalana sp or Ligonipes sp with Ligonipes sp being more prominent. This would rule out Damoetas sp. 2. The length of the metatarsus + tarsus suggest Jodalana sp or Damoetas sp. I've noticed that this is quite long and thin on Ligonipes which doesn't stand out to me for this individual. 3. Colour ratio and distribution can vary for Jodalana lutea from a portion of the upper abdomen being yellow to the entire abdomen being yellow. I think it can vary on the legs too.
Bron wrote:
   10 May 2020
Your close looks are excellent Yumi! I agree :) Judalana lutea isn't included in CNM though... So what next?
   10 May 2020
We can add it when the system is fully operational

Thanks Yumi
YumiCallaway wrote:
   1 Oct 2022
Good evening all 😊. I am reviewing some ID and I'd like to propose another look at this sighting and the two proceeding J. lutea sightings on CNM. This one has been on my mind ever since our discussion as I remember it being difficult with lots of possibilities and suggestions. I have a little more experience and practice since then, and we may have fresh ideas now, or new minds who have joined us since! I will explain my observations, and I would love to hear everyone's thoughts!
I think it is worthwhile to re-evaluate between Judalana lutea (p. 256 for Whyte & Anderson, 2017) and Rhombonotus gracilis (p. 298 in W. & A., 2017) as Cath had initially suggested.
Initially, R. gracilis was deemed to be too small with the 3mm maximum size mentioned. However, even in the identified spiders in the 2017 edition from Whyte and Anderson, the female was given to be 5mm and the male 4mm β€” both of which are larger than this limit we considered. This sightings size is recorded as 5mm to 12mm which overlaps with the species size range.

Next, for colouration and physical features. Colouration does apear to vary between individuals in J. lutea, so this colour could be within the diversity expected of the species. Looking at R. gracilis however, the colouration already matches sample photos of slightly yellowed brown (to my eyes :)), being more likely.
In 2020, we mentioned the fringes on the legs which we weren't sure ofβ€”both species have somewhat "hairy" front legs and can have fringing. So this wouldn't be a reliable determinant for this comparison 😊.
For the top of the carapace (head), this sighting seems to have dense hairs visible to us, especially in the second photo. This matches R. gracilis, whereas J. lutea seems to have sparse or little hairs that are visibly apparent in the same area.
We could also compare the abdomen shape, where J. lutea is quite slim and uniform in width, while R. gracilis appears to have a slight but apparent bulge after their patch of colour. Do you see a slight bulge? (There seems to be in the 1st photo for me)
Mostly, it is the side of the abdomen that I would like to draw attention to. Close to where the colour transitions from light to dark on the abdomen, we can see a strip of white on each side. This line doesn't seem to go around, disappearing on the top and only visible on the sides. This feature is clearly one displayed by R. gracilis (Whyte & Anderson, 2017, top of p.298 reference photos), where it appears to be absent in J. lutea for two species which otherwise feel difficult to distinguish.
On a final note, I have not recently checked the distribution of these species, but if my memory serves me well, the expected distribution range of J. lutea was concentrated in QLD. (I'm not too sure! I will look for the research paper if anyone is interested 😊. The two in Whyte and Anderson are from QLD and Grafton (NSW, but close to the border with QLD)). In contrast, one of the sample images of Whyte and Anderson are from Queanbeyan; pretty much just next door to us 😊

I will leave R. gracilis as a suggestion for now for anyone to comment their thoughts before any concrete decisions are made. What do you all think?

I hope these thoughts open a discussion and we can review any changes if they are due! Thank you to CathB and to everyone else for ID so far! Bron, we will keep giving our best IDs 😊. Hopefully we can learn more about our spiders together this way and have some groundwork for future sightings similar to this one.
   4 Oct 2022
Thanks for the detailed research Yumi. You have convinced me - also Rainer Richter has posted a similar looking spider as Rhombonotus gracilis on INaturalist
https://inaturalist.ala.org.au/observations/101868516
Cheers Michael Mulvaney
Bron wrote:
   3 Jan 2023
Thanks Yumi I've been away from CNM for a few months - just catching up a bit during the break. I confirmed your id I hope this is ok... Happy New Year! Cheers Bron

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Nearby sightings

Page 7 of 12 - image sightings only

Trichiocercus sparshalli (Sparshall's Moth) at Melba, ACT - 7 Jan 2021 by Bron
Hypobapta diffundens (Diffundens Grey) at Melba, ACT - 7 Jan 2021 by Bron
Barea codrella (A concealer moth) at Melba, ACT - 7 Jan 2021 by Bron
Cleora displicata (A Cleora Bark Moth) at Melba, ACT - 7 Jan 2021 by Bron
Culladia cuneiferellus (Crambinae moth) at Melba, ACT - 6 Jan 2021 by Bron
Stibaroma undescribed species MOV sp.(2). (A Line-moth.) at Melba, ACT - 6 Jan 2021 by Bron
Maroga melanostigma (Pecan Stem Girdler) at Melba, ACT - 5 Jan 2021 by Bron
Scopula rubraria (Reddish Wave, Plantain Moth) at Melba, ACT - 5 Jan 2021 by Bron
Dysbatus undescribed species (A Line-moth) at Melba, ACT - 5 Jan 2021 by Bron
Stangeia xerodes (A plume moth) at Melba, ACT - 5 Jan 2021 by Bron
Circopetes obtusata (Grey Twisted Moth) at Melba, ACT - 5 Jan 2021 by Bron
Caloptilia azaleella (Azalea Leafminer) at Melba, ACT - 5 Jan 2021 by Bron
Epiphyas postvittana (Light Brown Apple Moth) at Melba, ACT - 5 Jan 2021 by Bron
Aporoctena undescribed species (A Geometrid moth) at Melba, ACT - 5 Jan 2021 by Bron
Orthaga thyrisalis (Teatree Web Moth) at Melba, ACT - 5 Jan 2021 by Bron
Destolmia lineata (Streaked Notodontid Moth) at Melba, ACT - 4 Jan 2021 by Bron
Eudesmeola lawsoni (Lawson's Night Moth) at Melba, ACT - 4 Jan 2021 by Bron
Ardices curvata (Crimson Tiger Moth) at Melba, ACT - 4 Jan 2021 by Bron
Diarsia intermixta (Chevron Cutworm, Orange Peel Moth.) at Melba, ACT - 4 Jan 2021 by Bron
Arhodia lasiocamparia (Pink Arhodia) at Melba, ACT - 4 Jan 2021 by Bron
Sorama bicolor (Two-coloured Notodontid) at Melba, ACT - 4 Jan 2021 by Bron
Isomoralla pyrrhoptera (A concealer moth) at Melba, ACT - 4 Jan 2021 by Bron
Araneus circulissparsus (species group) (Speckled Orb-weaver) at Melba, ACT - 4 Jan 2021 by Bron
Empicoris sp. (genus) (Thread-legged assassin bug) at Melba, ACT - 3 Jan 2021 by Bron
Bathytricha truncata (Sugarcane Stem Borer, Maned Moth) at Melba, ACT - 3 Jan 2021 by Bron
Idaea inversata (Purple Wave) at Melba, ACT - 3 Jan 2021 by Bron
Tracholena sulfurosa (A tortrix moth) at Melba, ACT - 3 Jan 2021 by Bron
Stathmopoda megathyma (A concealer moth) at Melba, ACT - 3 Jan 2021 by Bron
Gelechioidea (superfamily) (Unidentified Gelechioid moth) at Melba, ACT - 3 Jan 2021 by Bron
Tortricopsis pyroptis (A Concealer moth (Wingia Group)) at Melba, ACT - 3 Jan 2021 by Bron
Prasinocyma semicrocea (Common Gum Emerald moth) at Melba, ACT - 3 Jan 2021 by Bron
Ardices canescens (Dark-spotted Tiger Moth) at Melba, ACT - 3 Jan 2021 by Bron
Dichromodes estigmaria (Pale Grey Heath Moth) at Melba, ACT - 3 Jan 2021 by Bron
Entometa undescribed species nr fervens (Common Gum Snout Moth) at Melba, ACT - 3 Jan 2021 by Bron
Meranda susialis (Three-lined Snout) at Melba, ACT - 3 Jan 2021 by Bron
Agriophara (genus) (A concealer moth) at Melba, ACT - 3 Jan 2021 by Bron
Heliocausta undescribed species (A concealer moth) at Melba, ACT - 3 Jan 2021 by Bron
Cyneoterpna wilsoni (Cyneoterpna wilsoni) at Melba, ACT - 3 Jan 2021 by Bron
Endrosis sarcitrella (White-shouldered House Moth) at Melba, ACT - 3 Jan 2021 by Bron
Scopula rubraria (Reddish Wave, Plantain Moth) at Melba, ACT - 3 Jan 2021 by Bron
Hypobapta diffundens (Diffundens Grey) at Melba, ACT - 3 Jan 2021 by Bron
Nyctemera amicus (Senecio Moth, Magpie Moth, Cineraria Moth) at Melba, ACT - 3 Jan 2021 by Bron
Cosmodes elegans (Green Blotched Moth) at Melba, ACT - 3 Jan 2021 by Bron
Proteuxoa provisional species 2 (A Noctuid moth) at Melba, ACT - 3 Jan 2021 by Bron
Etiella behrii (Lucerne Seed Web Moth) at Melba, ACT - 3 Jan 2021 by Bron
Heteromicta pachytera (Galleriinae subfamily moth) at Melba, ACT - 3 Jan 2021 by Bron
Crocidosema plebejana (Cotton Tipworm Moth) at Melba, ACT - 3 Jan 2021 by Bron
Psaroxantha calligenes (Psaroxantha calligenes) at Melba, ACT - 3 Jan 2021 by Bron
Hygraula nitens (Pond Moth) at Melba, ACT - 2 Jan 2021 by Bron
Blastobasis (genus) at Melba, ACT - 2 Jan 2021 by Bron
Spectrotrota fimbrialis (A Pyralid moth) at Melba, ACT - 2 Jan 2021 by Bron
Holocola triangulana (A Tortricid Moth) at Melba, ACT - 2 Jan 2021 by Bron
Olethreutinae (subfamily) (Unidentified leaf roller) at Melba, ACT - 2 Jan 2021 by Bron
Diatenes aglossoides (An Erebid Moth) at Melba, ACT - 2 Jan 2021 by Bron
Meritastis undescribed species (A Tortricid moth) at Melba, ACT - 2 Jan 2021 by Bron
Athetis tenuis (Plain Tenuis Moth) at Melba, ACT - 2 Jan 2021 by Bron
Chrysodeixis eriosoma (Green Looper) at Melba, ACT - 2 Jan 2021 by Bron
Faveria tritalis (Couchgrass Webworm) at Melba, ACT - 2 Jan 2021 by Bron
Didymoctenia exsuperata (Thick-lined Bark Moth) at Melba, ACT - 2 Jan 2021 by Bron
Oenochroa dinosema (A Concealer moth) at Melba, ACT - 1 Jan 2021 by Bron
Olbonoma triptycha (Chezela Group) at Melba, ACT - 1 Jan 2021 by Bron
Proteuxoa provisional species 1 at Melba, ACT - 1 Jan 2021 by Bron
Philobota philostaura at Melba, ACT - 1 Jan 2021 by Bron
Thrincophora impletana (a Tortrix moth) at Melba, ACT - 1 Jan 2021 by Bron
Cerdistus sp. (genus) (Yellow Slender Robber Fly) at Melba, ACT - 1 Jan 2021 by Bron
Ocrasa albidalis (A Pyralid moth) at Melba, ACT - 1 Jan 2021 by Bron
Trachymela sp. (genus) (Brown button beetle) at Melba, ACT - 1 Jan 2021 by Bron
Ectropis excursaria (Common Bark Moth) at Melba, ACT - 1 Jan 2021 by Bron
Helicoverpa (genus) (A bollworm) at Melba, ACT - 31 Dec 2020 by Bron
Gastrina cristaria (Wave-lined Geometrid) at Melba, ACT - 31 Dec 2020 by Bron
Psaroxantha undescribed species (A concealer moth) at Melba, ACT - 31 Dec 2020 by Bron
Oenochroa and Artiastis (genera) at Melba, ACT - 31 Dec 2020 by Bron
Microdes squamulata (Dark-grey Carpet) at Melba, ACT - 31 Dec 2020 by Bron
Macrobathra desmotoma ( A Cosmet moth) at Melba, ACT - 31 Dec 2020 by Bron
Neodialineura striatithorax (A therevidae fly) at Melba, ACT - 31 Dec 2020 by Bron
Hypobapta diffundens (Diffundens Grey) at Melba, ACT - 31 Dec 2020 by Bron
Philobota philostaura at Melba, ACT - 31 Dec 2020 by Bron
Diatenes aglossoides (An Erebid Moth) at Melba, ACT - 31 Dec 2020 by kasiaaus
Olbonoma triptycha (Chezela Group) at Melba, ACT - 31 Dec 2020 by Bron
Aporocera (Aporocera) sculptilis (Leaf beetle) at Melba, ACT - 31 Dec 2020 by kasiaaus
Aporocera (Aporocera) sculptilis (Leaf beetle) at Melba, ACT - 31 Dec 2020 by Bron
Faveria tritalis (Couchgrass Webworm) at Melba, ACT - 31 Dec 2020 by Bron
Edosa fraudulens (Tineidae) at Melba, ACT - 31 Dec 2020 by Bron
Proteuxoa sanguinipuncta (Blood-spotted Noctuid) at Melba, ACT - 31 Dec 2020 by Bron
Proteuxoa sanguinipuncta (Blood-spotted Noctuid) at Melba, ACT - 31 Dec 2020 by kasiaaus
Isopeda sp. (genus) (Huntsman Spider) at Melba, ACT - 31 Dec 2020 by Bron
Epiphyas postvittana (Light Brown Apple Moth) at Melba, ACT - 31 Dec 2020 by Bron
Cleora displicata (A Cleora Bark Moth) at Melba, ACT - 31 Dec 2020 by Bron
Pterohelaeus piceus (Pie-dish beetle) at Melba, ACT - 31 Dec 2020 by kasiaaus
Diarsia intermixta (Chevron Cutworm, Orange Peel Moth.) at Melba, ACT - 31 Dec 2020 by kasiaaus
Cleora displicata (A Cleora Bark Moth) at Melba, ACT - 31 Dec 2020 by kasiaaus
Helpis minitabunda (Threatening jumping spider) at Melba, ACT - 31 Dec 2020 by Bron
Heteromicta pachytera (Galleriinae subfamily moth) at Melba, ACT - 31 Dec 2020 by Bron
Heteromicta pachytera (Galleriinae subfamily moth) at Melba, ACT - 31 Dec 2020 by Bron
Philobota philostaura at Melba, ACT - 31 Dec 2020 by Bron
Garrha phoenopis (Garrha phoenopis) at Melba, ACT - 31 Dec 2020 by Bron
Garrha phoenopis (Garrha phoenopis) at Melba, ACT - 31 Dec 2020 by kasiaaus
Macrobathra desmotoma ( A Cosmet moth) at Melba, ACT - 31 Dec 2020 by kasiaaus
Thrincophora impletana (a Tortrix moth) at Melba, ACT - 31 Dec 2020 by Bron
Merophyas divulsana (Lucerne Leafroller) at Melba, ACT - 31 Dec 2020 by kasiaaus

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