Cardiocondyla itsukii, Seifert, Bernhard, Okita, Ichiro & Heinze, Jürgen, 2017

Seifert, Bernhard, Okita, Ichiro & Heinze, Jürgen, 2017, A taxonomic revision of the Cardiocondyla nuda group (Hymenoptera: Formicidae), Zootaxa 4290 (2), pp. 324-356 : 339-343

Cardiocondyla itsukii sp. nov.

Tab. 1, Figs. 10 – 12

Etymology. The species is dedicated to Itsuki Okita, the son of the junior author.

Type material. The holotype plus 8 paratypes (4 workers, 2 gynes and 2 males) are on three pins labelled " JAP: 34.72297 N, 137.83881 E / Shizuoka Pref. Iwata-shi, 12 m / street margin in rural land/ leg. I. Okita 2010.09.05-81". The pin with the holotype carries a red type label " Holotype (top specimen) / & Paratypes / Cardiocondyla itsukii / Seifert & Okita " and the two pins with paratypes have labels " Paratypes / Cardiocondyla itsukii / Seifert & Okita ". These are deposited at SMNG . Five additional paratype workers are deposited at CAS. Furthermore, 120 workers, 86 gynes, and 1 ergatoid male are stored in ethanol at MNEHS.

All material examined. A total of 45 nest samples with 108 workers were subject to NUMOBAT investigation.

Bhutan: Puntsholing, 1972.04.0 5, [26.86, 89.39]. China: Nanning, 1966.06.0 2, [22.82, 108.30]. Hawaii Islands : Hawaii, 2002.04.0 9, No PKS127/130, [19.442, -155.316] ; Hawaii, 2002.04.xx, No PDK129/131, [20.579, -156.136] ; Hawaii: Mauna Kea, 2001.06.14, [19.726, -155.447] ; Hawaii: Mauna Kea, 2002.06.13, No 0 49, (GenBank DQ 023088 ), [19.726, -155.447]; Kauai, 2006.09.0 4, No HI 54, [22.129, -159.661]; Maui: 2001.08.18, No PKS121, [20.681,-156.136]; Maui, 2003.06.16, No 173, [20.747, -156.247]; Maui, 2003.07.0 3, No 170, [20.749, -156.241]; Maui, 2003.xx.xx, No 144, [20.751, -156.240]; Maui: Kapalua, 1990.02.23, [21.000, - 156.659]; Oahu: Waikane Trail, 1989.09.30, [21.483, -157.856]. India: Bhopal- 130 km SE, Pachmarhi, 2006.06.26, [22.47, 78.43]; Calcutta, pre 1920 (Rothney-Smith), [22.60, 88.40]; Dehradun- 10 km SE, 1996.xx.xx, No 552, [30.21, 78.13]; East India , pre 1920 (Rothney-Smith), [23.6, 88.4] . Indonesia: Java: Cibodas , 2000.01.0 5, No I6, [-6.83, 107.68] ; Sulawesi: Dumoga Bone National Park, 1985.xx.xx, [0.58, 123.90]. Japan: Fukuroi, 2010.10.24, No 88, (GenBank LC199504 ), [34.791,137.865]; Hamamatsu , 2010.08.0 7, No 71 (GenBank LC199505 ), [34.716, 137.604]; Iriomote , 2013.09.18, No 199 (GenBank LC199506 ), [24.258, 123.865]; Ishigaki , 2013.09.18, No 197 (GenBank LC199507 ), [24.337, 124.154]; Iwakuni , 2013.08.27, No 175 (GenBank LC199508 ), [34.076, 132.210]; Iwata-shi , 2010.09.0 5, No 81 (GenBank LC199509 ), type Cardiocondyla itsukii , [34.723, 137.839] ; Nagasaki: Mt. Unzen , 1983.08.20, [32.760, 130.301] ; Nagasaki: Mt. Unzen without date, [32.760, 130.301]; Nakagusuku, 2013.06.0 7, No 148 (GenBank LC199510 ), [26.275, 127.781]; Nanjo, 2013.06.0 2, No 128 (GenBank LC199511 ), [26.178, 127.828]; Ogasawara Island , 1972.07.29, [27.10, 142.20]; Ogasawara Island , 1977.02.11, [27.10, 142.20] ; Okinawa: Ada Island, 1994.09.22, (GenBank DQ 023082 ), [26.74, 128.32] ; Okinawa: Izena Island, 1985.03.31, [26.93, 127.94] ; Okinawa : Okinawa, 2003.06.26, [26.50, 127.94]; Tahara, 2011.08.0 9, No 107 (GenBank LC199512 ), [34.587, 137.026] ; Wakayama, 2013.08.30, No 186 (GenBank LC199513 ), [34.288, 135.072]; Yaizu, 2010.10.31, No 94 (GenBank LC199514 ), [34.895, 138.347]. Kiribati: Enderbury Island , 2000.05.0 7, [-3.13, -171.09] . Nepal: Pohkara- 27 km NW, 1995.11.xx, [28.302, 83.781]: Pohkara vicinity, 1995.11.xx, No 975, [28.20, 83.98]. Philippines: Paloc, 1995.01, [14.580, 120.550]. Réunion: Le Port, 2007.05.21, No 17714, [-20.938, 55.295] . Sri Lanka: Bandarawella, 1988.01.16, [6.824, 80.994]; Nuwara Eliya, 1988.01.16, [6.953, 80.783]. Thailand: Koh Chiang, beach, 2004.01.xx, [12.048, 102.302].

Description of worker caste. Worker ( Tab. 1, Figs. 10 – 12 ): Head less elongated than in all other members of the C. nuda group, CL/CW 1.169. Postocular distance moderately large, PoOc/CL 0.444. Eyes relatively small, EYE 0.228. Frontal carinae immediately caudal of the FRS level parallel or very slightly converging ( Fig. 10 ). Foveolae on vertex without interspaces, deeply impressed, with 15 – 22 µm diameter, and with an inner corona (a flat tubercle) of 7 – 9 µm diameter having the base of a decumbent pubescence hair in its center. This type of sculpture can also be described as a strongly sculptured microreticulum. Longitudinal sculpture on vertex reduced; only frontal laminae, clypeus, and a narrow area on anteromedian vertex finely longitudinally carinulate; a weak semicircular rugosity is found around the antennal fossae. Lateral mesosoma on whole surface regularly and strongly microreticulate; longitudinal sculpture except for 4 – 6 weak and short carinulae on metapleuron entirely absent ( Fig. 11 ); dorsal promesonotum with more irregular reticulum the meshes of which have twice the diameter than on lateral mesosoma. Whole surface of petiole and postpetiole more shining, with a very fine microreticulum. The strength of sculpture on mesosoma and waist in particular shows considerable variation within the huge distributional range, without showing regional trends. Cuticular surface of first gaster tergite smooth and shining, a very delicate microreticulum with wide meshes becomes visible at higher microscopic resolution. Pubescence hair length on gaster tergites is the largest within the C. nuda group, PLG/CS 7.12% ( Fig. 12 ). Metanotal groove distinct but rather flat, MGr/CS 2.16%. Propodeal spines reduced to short dents. Petiolar profile in many specimens with a steeper frontal face compared to C. strigifrons and C. kagutsuchi . Petiole node slightly longer than wide. Postpetiole narrower than in C. mauritanica ; in dorsal view with clearly angulate sides and straight anterior margin that is clearly shorter than posterior margin ( Fig. 12 ); postpetiolar sternite flat, without any protrusions. Color most variable over the huge distributional range: most frequent are morphs with a medium brown mesosoma and waist, a dark brown head and a dark to blackish brown gaster but much lighter or darker color morphs are not rare. For morphometric data of 108 workers see Tab. 1.

Geographic range. C. itsukii shows a huge range extending over 17000 km from the Island Reunion in the Indian Ocean, over East India , Indochina , Japan and diverse Pacific Islands east to Hawaii . The most marginal, isolated populations on Island Reunion and Hawaii most probably have been founded by anthropogenous introduction. Despite showing tramp species properties C. itsukii is rare in the Indo-Malayan Archipelago where C. kagutsuchi and strigifrons dominate.

Diagnosis. See key.

Biology. On Hawaii it is one of the very few ants occurring in high densities in primary rain forests with Metrosideros sp. trees and Cibotium ferns and is found also at higher elevations on Mauna Kea volcano ( Krushelnycky et. al. 2005, Wetterer et. al. 1998). Biological traits of C. itsukii were studied by Frohschammer & Heinze (2009), Heinze et. al. (2013) and Okita et. al. (2015). Winged males are not known in C. itsukii but only wingless ergatoid males with more than one male usually being present in a colony. The males are in reproductive competition and use the strong shear-shaped mandibles to attack freshly eclosed rivals by crushing their heads or cutting-off appendages but males do not fight when in adult stage. As in C. mauritanica , the strictly intranidal mating and polygyny is considered as a preadaptation for a successful tramp species strategy. The total number of sexual offspring of queens is positively associated with their life-span. More fecund queens live longer than less fecund queens and early onset of sexual production does not negatively affect the queen’s life-span. The number of eggs present in colonies increased with queen’s age until shortly before death, indicating negligible reproductive senescence. Several queens produced only males late in their lives, suggesting the occurrence of sperm depletion.

Figures

FIGURE 10. Head of holotype of Cardiocondyla itsukii sp. nov. in dorsal aspect.

FIGURE 11. Lateral aspect of holotype of Cardiocondyla itsukii sp. nov.

FIGURE 12. Waist and gaster of holotype of Cardiocondyla itsukii sp. nov. in dorsal aspect.