Neocaledosynthemis, Fleck, 2024

Fleck, Günther, 2024, A remarkable new synthemistid from New Caledonia (Odonata: Anisoptera: Synthemistidae s. str.). Taxonomic and phylogenetic note on New Caledonian Synthemistidae and erection of a new genus, Zootaxa 5403 (3), pp. 320-330 : 328-329

Neocaledosynthemis gen. nov.

Type species. Synthemis fenella Campion

Other included species. Synthemis ariadne Lieftinck

Etymology. After New Caledonia and Synthemis Selys.

Justification and differential diagnosis

Material examined: male, female and larva (reared) of all New Caledonian species of synthemistids (female C. ariadne based on photos), except C. pamelae Davies and larva C. jeanlegrandi . In addition to characters accessible in literature for non-New-Caledonian synthemistids male, female and larva of Synthemis tasmanica Tillyard , Austrosynthemis cyanitincta Tillyard , Tonyosynthemis claviculata Tillyard , Choristhemis flavoterminata Martin , Palaeosynthemis cyrene Lieftinck , Archaeosynthemis spp. , and Eusynthemis spp. were also examined.

Carle (1995), on the supposed basis of a pair of male apomorphic characters (see below discussion), erected the genus Calesynthemis to accomodate all Synthemis species from New Caledonia ie Synthemis miranda (type species), S. ariadne , S. campioni Lieftinck , S. fenella , S. flexicauda Campion , S. montaguei Campion and S. serendipita . As these species are all endemic, the genus Calesynthemis is also restricted to New Caledonia.

Davies (2002) did not recognize the genus Calesynthemis and described under Synthemis , a new species ( S. pamelae ). Given the available characters and the possible close affinity with C. miranda (being “its nearest relative” after Davies), S. pamelae should have probably been placed in Calesynthemis sensu Carle (1995) .

The New Caledonian synthemistids, even if probably rather closely related to true Synthemis (ie S. eustalacta Burmeister from South East Australia and S. tasmanica , from Tasmania) are nevertheless sufficiently different to be removed from this genus. Indeed, the true Synthemis have, among others, distinctly different male hamuli posteriores, male vesica spermalis V 1, male organisation of S2 ventral tergum, male epiproct, female ovipositor, FW relative position of arculus, HW anal loop construction, larval frontal plate, larval premental distal margin, and larval mask setal organisation.

Fleck (2005, in Fleck et al. 2020) considered New Caledonian synthemistids as Synthemis sensu lato, because the species S. ariadne and S. fenella were not considered belonging to Calesynthemis , and Fleck & El Adouzi (2013) did not treat New Caledonian synthemistids and mentioned “New Caledonian synthemistids are in need of a revision and probably to be split into two genera”. In the matter of fact, the species S. ariadne and S. fenella are distinctly different from other Calesynthemis , not only by virtue of their smaller size, but for example their larvae are remarkable and unique among synthemistids by the absence of long body setae giving them a strong glabrous and finely granulose aspect, and by the absence of dentition on the labial palps. The following characters permit the separation of S. fenella and S. ariadne from other New Caledonian species:

- All discoidal triangles free. They are generally free in S. fenella , in S. ariadne rarely crossed in one or even two wings. In other New Caledonian representatives discoidal triangles are crossed at least in one pair of wings (usually on both pair of wings). HW discoidal triangle is generally free in male C. miranda and occasionally in female.

- Arculus not strongly shifted distal to Ax2. In S. fenella and S. ariadne the arculus is often placed slightly proximal to Ax2 or at Ax2, it is regularly shifted slightly distally (rarely distinctly in HW). In most other species, except C. flexicauda , the origin of arculus is distinctly shifted distal to Ax2, most of the time in both pair of wings. In C. flexicauda it is placed at Ax2 or slightly distally shifted. Note that in some Eusynthemis Förster and allied genera, the arculus is shifted distal to Ax2.

- Male cerci not longer than S9+10. In S. fenella they are about as long as S9+10 and in S. ariadne they are slightly shorter than S9+10. In other species they are longer, most of the time distinctly so.

- Male penis dh1 and dh2 placed on a common stem ( Fig. 23 , see arrow, compare with Fig. 8 ). In all other species they are distinctly separated or approximate on V 4, never placed on a common stem.

- Female V 1 (vulvar lamina) short and stout with U-shaped medial notch. In New Caledonian female synthemistids the V 1 are in their proximal part parallel and contiguous, in their distal part divergent, the notch being V-shaped or U-shaped; the base of the notch presents additionally a pair of denticles. In S. fenella and S. ariadne V 1 is restricted to the basal 1/3 to basal 1/4 of S9 sternum (contra Carle, 1995) (and also shorter than 1/2 the length of S10, contra Carle, 1995) with proximal part strongly reduced, and notch U-shaped in S. fenella , and probably derived from the S. fenella type in S. ariadne since distal part is similar to that of S. fenella but basal part shows shortly divergent inner margins (apparently unique within New Caledonian synthemistids). In other species, except C. serendipita , the V 1 are overlapping about 1/2 of S9 sternum, their proximal part is rather long and their notch V-shaped. In C. serendipita the ovipositor is short, hardly longer than 1/3 of S9 (contra Carle 1995), with notch somewhat U-shaped, but with basal part having valves contiguous over a relatively long distance (considering the distal part only, probably a convergence with S. fenella and S. ariadne given the close affinity of C. serendipita with C. campioni ).

- Female cerci not longer than S9+10. In S. fenella they are about as long as S9, in S. ariadne slightly shorter than S9+10. In other species they are generally distinctly longer than S9+10 except C. miranda where they appear up turned and shorter than S9+10.

- Larva glabrous, deprived of long setae and long hair-like setae and with fine granulose appearance (unique character within synthemistids). All other larvae present long setae and/or long hair-like setae at least on frontal plate, occipital lateral margins, pronotal lateral lobes, lateral margins of thorax and abdomen.

- Larva with distal margin of labial palp lacking clear dentition (a unique character within synthemistids). All other larvae have distinct dentition.

- Larva with only 6 or fewer antennomeres (apparently unique within synthemistids). Contrary to the claim of Lieftinck (1976), from 12 F-0 and 2 F-1 checked S. fenella larvae from different localities, only one F-0 seems to have 7 antennomeres on one antenna (moreover the character is not clearly cut since the interantennomeral joint is not clearly marked!); three specimens exhibit 5 antennomeres in a least one antenna. All S. ariadne checked larvae (6 F-0 and 2 F-1) have 6 antennomeres. Thus, S. fenella and S. ariadne larvae can be considered to have 6 antennomeres (sometimes with one less, very exceptionally, and aberrantly, with one more). All other species have 7 antennomeres, and antennae, comparatively to body dimension, longer.

- Larva with only 2 long premental setae and 2 or 3 palpal setae (apparently unique within synthemistids). Other larvae have at least 3 long premental setae and 4 palpal setae.

Considering all the above-mentioned characters, any of them unique among synthemistids and considered synapomorphic, S. fenella (type species) and S. ariadne are placed in the genus Neocaledosynthemis .

Figures

FIGURES 22–24. 22. Comparison of paratype female Calesynthemis jeanlegrandi sp. nov. (left) and female Calesynthemis serendipita (right). 23. Neocaledosynthemis gen. nov. N. fenella. Vesica spermalis (or penis) in right lateral view.Arrow indicates common stem of dh1 and dh2. 24. Synthemis tasmanica. Vesica spermalis (or penis). V3 and V4 in right lateral view. Note the remarkable similarity with V3 and V4 of Neocaledosynthemis fenella gen. nov.

FIGURES 6–10. Calesynthemis jeanlegrandi sp. nov., male holotype. Vesica spermalis (or penis). 6. Left general view. 7. Ventral general view. 8. Detail of V2–V4 in right lateral view. 9. Detail of V3 in ventral view. 10. Detail of V3–V4 in anteroventral view. Note the strongly divergent branches of dh1.