Temnothorax haveni Lee, Hamer & Guénard, 2023

Hamer, Matthew T., Lee, Roger H. & Guénard, Benoit, 2023, First record of the genus Temnothorax Mayr, 1861 (Formicidae: Myrmicinae) in Hong Kong, with descriptions of two new species, European Journal of Taxonomy 879 (1), pp. 116-135 : 124-129

Temnothorax haveni Lee, Hamer & Guénard sp. nov.

urn:lsid:zoobank.org:act:D5640CE1-BA4A-469B-959B-444695F094C3

Figs 3–5

Diagnosis

Head subquadrate; lateral margins of head subparallel in full face view; clypeus with longitudinal carinae extending only in the anterior half; scapes not reaching occipital head margin; in lateral view promesonotum convex, followed by a concave mesopropodeal depression at the junction with the propodeum; promesonotal suture visible in lateral view only; metanotal groove absent; propodeal spines well-developed with thick base, long and curved pointing backwards; head and mesosoma glabrate; head, mesosoma and gaster covered with scarce erect, stout setae. Core body concolorous ochreous-yellow.

Etymology

The specific epithet ‘haveni’ is a noun in English. This was the first species of Temnothorax recorded in Hong Kong, one of the most urbanized cities but with 40% of the land designated as protected areas for biodiversity conservation, providing havens for countless species and those awaiting discovery.

Material examined

Holotype CHINA • worker; Hong Kong SAR, Hong Kong Island, Aberdeen Reservoir; 22°15′32.04″ N, 114°9′34.56″ E; 190 m a.s.l.; 27 Jun. 2017; Roger H. Lee and Yuet Yin Ling leg.; ground baiting; ZRC RHL03433 .

Paratypes (n = 8) CHINA – Hong Kong SAR • 1 worker; Mui Wo ( Lantau Trail ); 22°15′41.76″ N, 114°0′6.84″ E; 38 m a.s.l.; 15 Aug. 2022; André Ibáñez and Matthew T. Hamer leg.; Winkler; HKBM ANTWEB1010974 [MW1T1W4-5] • 1 worker; Hong Kong Island, Lung Fu Shan ; 22°16′45.48″ N, 114°8′13.92″ E; 231 m a.s.l.; 14Apr. 2022; Matthew T. Hamer leg.; hand collection on ground; HKBM ANTWEB1010976 • 1 worker; Hong Kong Island, Aberdeen Reservoir ; 22°15′32.04″ N, 114°9′34.20″ E; 192 m a.s.l.; 27 Jun. 2017; Roger H. Lee leg.; ground baiting; HKBM RHL03467 [RHL5265] • 1 worker; Hong Kong Island, The Peak ; 22°16′24.96″ N, 114°8′20.04″ E; 391 m a.s.l.; 11 Jul. 2017; Roger H. Lee leg.; hand collection; HKBM RHL03474 [RHL5272] • 1 worker; Tai Po Kau Nature Reserve ; 22°25′12.72″ N, 114°10′35.76″ E; 349 m a.s.l.; 23 Aug. 2022; Shaolin Han leg.; arboreal baiting, 20 meters high; IBBL ANTWEB1010993 [TPK_S1_T3] • 1 worker; Fanling, Fanling Golf Course ; 22°29′25.44″ N, 114°6′37.08″ E; 48 m a.s.l.; 23 May 2022; Matthew T. Hamer and André Ibáñez leg.; ground baiting; IBBL ANTWEB1010975 [FGE1T2B2-1] • 1 worker; Girl Guides Pok Hong Campsite ; 22°22′16.68″ N, 114°11′46.68″ E; 84 m a.s.l.; 24 Jun.–1 Jul. 2022; Matthew T. Hamer and André Ibáñez leg.; flight interception vane trap; IBBL ANTWEB1010987 [GGPH2V2-1] • 1 worker; Tsing Yi, Tsing Yi Peak ; 22°20′35.16″ N, 114°5′59.64″ E; 244 m a.s.l.; 16 Mar. 2018; R. Cheung and M. Law leg.; Winkler; IBBL ANTWEB1016704 [TYP S1-R] .

Description

MEASUREMENTS (n = 9). Holotype (n = 1); CL 0.55; CW 0.54; CWb 0.50; SL 0.4; WL 0.65; SPST 0.23; PEL 0.29; PPL 0.15; PEH 0.16; PPH 0.16; PW 0.34; SPBA 0.12; SPTI 0.17; PEW 0.13; PPW 0.18; ATL 0.62; HS 0.52; SI 80.6; CI 91.58; SBI 23.2; PSI 35.02; PWI 145.6; PLI 194.63; TL 2.26. Paratypes (n = 8); HL 0.51–0.55; CW 0.5–0.55; CWb 0.44–0.5; SL 0.35–0.41; WL 0.61–0.69; SPST 0.23–0.29; PEL 0.25–0.32; PPL 0.12–0.17; PEH 0.14–0.18; PPH 0.15–0.16; PW 0.3–0.34; SPBA 0.1–0.17; SPTI 0.11–0.18; PEW 0.11–0.12; PPW 0.16–0.18; ATL 0.46–0.58; HS 0.47–0.53; SI 75.71–87.67; CI 86.22–92.04; SBI 21.1–37.66; PSI 36.99–41.84; PWI 140.16–151.35; PLI 160–229.41; TL 1.99– 2.22.

HEAD. In full face view, head subquadrate, longer than broad (CI 86.22–92.04), with weakly convex sides and occipital margin, rounded occipital corners. Clypeus widely inserted between antennal lobes; anterior margin weakly convex and angulate medially; three clypeal carinae present. Mandible broadly triangular, masticatory margin with five teeth, apical most tooth larger than preceding teeth. Frontal carinae weak but moderately long, extends from the antennal insertions to the area of the vertex; frontal lobes present. Antenna with 12 segments terminating in an incrassate three-segmented club; apical segment longer and broader than following segments. Scape of medium length (SI 78.57–87.67), terminating before posterior corners of the head. Eye convex; located medially on head and extending laterally beyond the cephalic capsule. In lateral view, eyes composed of 9–10 ommatidia across the longest width. In dorsal view, occipital carina present but weakly developed.

MESOSOMA. In dorsal view, mesosoma widest at the middle portion of pronotum; humeri widely rounded; mesosoma weakly tapering posteriorly, reaching a minimum width at the anterior part to propodeum. Promesonotal suture absent dorsally but present laterally. Metanotal groove absent. In lateral view, promesonotum convex and follow by a distinct concavity at mesonotum, forming a weak promesonotal dome. Propodeal spiracle circular. Propodeal lobe round. Propodeal spines well-developed, long, and slightly downward curved toward the end; spines longer than the distance between their bases (SPST 0.23–0.29; SBPA 0.10–0.17), spines feebly diverge postero-laterally from the dorsal view. In lateral view, propodeal declivity subtly concave.

METASOMA. In lateral view, petiole subtriangular, longer than high. Anterior face of petiole distinctly longer than posterior face; node with acute apex. Postpetiole short and convex. In dorsal view, postpetiole subquadrate; distinctly wider than petiole. Gaster wider than postpetiole; first gastral tergite long, as long as mesosoma; anterolateral corners obtusely angled.

SETAE. In full face view, mandible dorsum with well-spaced sub-decumbent pilosity; anterior clypeal margin with two long and tapering setae on either side of clypeal median. Several sub-erect setae present on anterior clypeal margin, directed towards clypeal median. From clypeal dorsum to cephalic dorsum, covered with sparse, stout and erect setae that are spaced roughly equidistantly. Scapes and subsequent antennal segments with sub-decumbent to semi-erected pilosity. In lateral view, ventral part of head with scare erect to semi-erect pilosity, intertwined with stout-erect setae. Mesosoma with long, erect setae arranged in series of transverse rows, normally not more than five pairs. Mesosoma dorsum also with sparse, short decumbent and appressed setae between the long, erect, setae pairs; of propodeal spines also with a single pair of setae sub-apically. Posterior face of petiole dorsum with a few pairs of erect setae, anterior face lacking setae. Postpetiole dorsum with a few pairs of erect setae. Gastral tergite with scarce erect stout setae in varying length arranged in loose rows. Femur and tibia with short and appressed pubescence.

SCULPTURE. In full face view, mandibles overlain by very weak lateral striae. Majority of clypeus dorsum smooth other than short, longitudinal carinae that begin at the clypeal anterior border. Dorsum of head, from clypeus to posterior head corners, glabrate. Dorsal pronotum, mesonotum and propodeum glabrate. Pronotum, mesonotum and propodeum overlain with faint but weak lateral striae laterally. Petiole and postpetiole dorsally and laterally weekly punctate-recticulate. Gaster comparatively smooth and shining.

COLOUR. Core body concolorous ochreous-yellow. Setae across whole of body yellowish white. Gaster with dark brown patches laterally from dorsal and lateral view.

Comments

Temnothorax haveni sp. nov. would key out to T. zhejiangensis in Zhou et al. (2010) and shares several morphological characters. These characters include the presence of erect setae on the mesosomal dorsum, a pair of long slightly downcurved propodeal spines, humeri rounded in dorsal view, a short petiole peduncle and a petiole that is longer than high in lateral view. However, various characters differ, including the sculpture on the head dorsum, lateral and dorsum mesosoma being predominately glabrate in T. haveni rather than punctate in T. zhejiangensis . The mesosomal outline differs greatly between both species with a convex promesonotum followed by a distinct concavity forming a weak promesonotal dome in T. haveni but only slightly convex across its whole length in T. zhejiangensis . The petiole peduncle is narrower and slightly longer in T. haveni than in T. zhejiangensis being broader and shorter. The petiole node in T. haveni has an acute dorsal apex within T. zhejiangensis is subtriangular with a narrowly rounded dorsum. Similarly, T. haveni might be mistaken for T. ruginosus both species can be differentiated by size ( T. haveni WL 0.61–0.69; T. ruginosus WL (ML in Zhou et al. (2010)) 1.80–1.84), as well as head and mesosomal sculpturing and the mesosomal outline. Temnothorax haveni may also be mistaken for T. barrettoi sp. nov., however, both species can be differentiated by the glabrate sculpture and more scarce erect stout setae over the body of T. haveni . We believe the above characters distinctly differentiate T. haveni from its congeneric species due to their uniqueness and consistency across all specimens examined. In fact, the lack of sculpture, particularly on the head, combined with distinct mesopropodeal depression, makes T. haveni morphologically distinct amongst Chinese Temnothorax . Further description of species of Temnothorax from other regions of Southeast Asia were examined with no species satisfying all characters.

Natural history

Temnothorax haveni sp. nov. has been collected from semi-open to closed canopy secondary forests throughout the territory of Hong Kong. Specimens are mostly found within leaf litter samples but have also been attracted to ground baiting. One worker of T. haveni was collected twenty metres above the ground in a tree from an arboreal bait sample within a secondary forest. An additional specimen was hand collected along a waist high handrail and another from a flight interception trap (vane trap) hung from a tree at head height. These samples may indicate T. haveni forages on shrubs or understorey vegetation, as well as within trees and could therefore be a predominately arboreal species, which may also forage occasionally on the forest floor. However, it is difficult to rule out individuals falling from plants due to unintentional vegetation interaction by samplers, which may explain specimens from Winkler samples and ground hand collection. Moreover, the lack of any whole nest samples from the mostly ground based sampling effort in Hong Kong (e.g., Winklers), indicates this species may not nest in leaf litter, with only singletons found and no reproductive caste thus far collected.

While infrequently collected within Hong Kong, perhaps due to limited sampling towards arboreal species at this point, the species appears relatively widespread, being found on most larger islands and continental parts of the SAR ( Fig. 5 ). Temnothorax haveni sp. nov. is thus expected to be found in the nearby province of Guangdong which shares a similar climate and habitats as Hong Kong.

Figures

Fig. 3. Temnothorax haveni Lee, Hamer & Guénard sp. nov., holotype (RHL03433). A. Lateral view. B. Dorsal view. C. Head in full face view.

Fig. 4. Temnothorax haveni Lee, Hamer & Guénard sp. nov., holotype (RHL03433), morphological characters. A. Petiole and postpetiole in lateral view. B. Petiole and postpetiole in dorsal view. C. Mesosoma in dorsal view. D. First gastral tergite in dorsal view.

Fig. 5. Distribution map of Temnothorax Mayr, 1861 records from Hong Kong. The darker the green areas, the greater the tree canopy cover.