Microvelia minsa, Aiso & Ishikawa, 2024

Aiso, Takumi & Ishikawa, Tadashi, 2024, A new species of the small water strider genus Microvelia (Hemiptera: Heteroptera: Veliidae) from the Ryukyus, Japan, with notes on the distribution of M. kyushuensis, Zootaxa 5468 (2), pp. 350-360 : 351-358

publication ID	https://doi.org/ 10.11646/zootaxa.5468.2.6
publication LSID	lsid:zoobank.org:pub:2F1BB275-16B6-42B4-8B50-610F210C494E
DOI	https://doi.org/10.5281/zenodo.11638120
persistent identifier	https://treatment.plazi.org/id/4B192F63-FFE0-9C5D-33F2-FDE0FE95FEAF
treatment provided by	Plazi
scientific name	Microvelia minsa
status	sp. nov.

Treatment

Microvelia minsa sp. nov.

Japanese name: Minsâ-keshi-katabiroamembo

( Figs. 1–4 View FIGURE 1 View FIGURE 2 View FIGURE 3 View FIGURE 4 , 5A, B View FIGURE 5 , 6A View FIGURE 6 )

Microvelia kyushuensis View in CoL (non Esaki & Miyamoto 1955): Miyamoto (1964: 137; new record from Ishigaki-jima Is., the Ryukyus, Japan); Hayashi & Miyamoto (2005: 341, Fig. 30A; diagnosis, key, ecological notes, distribution) (part); Hayashi & Miyamoto (2006: 52, Fig. 1 View FIGURE 1 ; new record from Yonaguni-jima Is., the Ryukyus, Japan) (part); Hayashi & Miyamoto (2018: 383, Fig. 31A; diagnosis, key, ecological notes, distribution) (part).

Type series. All types of materials are preserved in the TUA. HOLOTYPE: apterous male, “Ômija-gawa Riv., Takana, Iriomote-jima Is., Taketomi-chô, Okinawa Prefecture, the Ryukyus, Japan, 27 III 2023, T. Aiso ”. GoogleMaps PARATYPES: [ Japan: the Ryukyus: the Yaeyama Islands] Miyara, Ishigaki-jima Is., 31 X 2021, T.Aiso (1 apterous male, 1 apterous female and 1 macropterous female); GoogleMaps Mt. Maese-dake, Ishigaki-jima Is., 26 I 2022, T. Naito (1 apterous male and 1 apterous female); GoogleMaps same as holotype (1 apterous male and 1 apterous female); GoogleMaps Iriomote, Iriomote-jima Is., 24.38811N 123.76733E, 10 VII 2020, T. Ishikawa (1 apterous male and 1 apterous female); GoogleMaps Hoshidate , Iriomote-jima Is., 3 IX 2021, H. Nozawa (8 apterous females and 1 macropterous female); GoogleMaps Hoshidate , Iriomote-jima Is., 24.3937N 123.7554E, 22–23 XI 2019, T. Ishikawa (1 apterous male and 1 apterous female); GoogleMaps Ôhama-nouen , Iriomote-jima Is., 24.37779N 123.75589E, 12 VII 2020, T. Ishikawa (1 apterous male and 1 apterous female); GoogleMaps Higawa, Yonaguni-jima Is., 3 XI 2021, T. Aiso (5 apterous males, 5 apterous females, 2 macropterous males and 2 macropterous females); GoogleMaps near Angaimidouchi , Yonaguni-jima Is., 5 IV 2022, Y. Yamaguchi (2 apterous males and 1 apterous female); GoogleMaps Mt. Imbi-dake , Yonaguni-jima Is., 25 V 2022, Y. Miyazaki (1 apterous male) GoogleMaps .

Other material examined. “Omotosan [in Japanese] 14.X.1963 ”, “ Microvelia Kyushuensis Es. Et Miy. ” (1 apterous female, used in Miyamoto (1964)) (KUM); “Omotosan [in Japanese] 14.X.1963 ” (1 apterous female, used in Miyamoto (1964)) (KUM).

Description. Apterous male ( Figs. 1A View FIGURE 1 , 2A View FIGURE 2 , 4 View FIGURE 4 , 5A View FIGURE 5 , 6A View FIGURE 6 ). Coloration: Body generally dark-gray, covered with dense gray pubescence ( Figs. 1A View FIGURE 1 , 2A View FIGURE 2 , 5A View FIGURE 5 ). Head dark-gray, with whitish areas around eyes. Eyes dark-red.Antennae dark-brown; bases of segments I and II yellow. Labial segments I–III yellow, and segment IV black. Pronotum anteriorly with white wide transverse band; wide transverse band with orange marking in middle; posterior margin of pronotum brown. Legs dark-brown; femora generally yellow in basal half and dark-brown in apical half. Abdomen dorsally dark-gray to blackish; mediotergite I gray along lateral and posterior margins, with orange round marking at center; mediotergites II, III, V and VI each with a pair of gray square markings; mediotergite VII gray for most parts, with blackish spot at center; dorsal laterotergites II–VII dark-gray to blackish on inner half and brown on outer half; brown parts of dorsal laterotergites II, III and VI often becoming paler; tergite VIII and pygophore brownishyellow.

Structure: Body elongate-oval, approximately 2.5 times as long as its maximum width. Head approximately 0.75 times as long as width across eyes, covered with long erect setae on apex. Antennae ( Fig. 4A View FIGURE 4 ) slender, slightly shorter than half of body length; segment I covered with short, decumbent to suberect setae; segments II–IV equipped with long erect setae on outer (anterior) side intermixed with short, decumbent to suberect setae; segment IV longest; proportional lengths of segments I–IV 1.1: 1.0: 1.3: 2.4. Pronotum transverse, approximately 0.45 times as long as its maximum width, coarsely punctate; punctures roughly arranged in 2–3 transverse lines; anterior margin shallowly concave; posterior margin convex. Meso- and metanotum concealed under pronotum except lateral parts of metanotum represented by small triangular lobe in dorsal view. Legs densely covered with short setae. Fore legs ( Fig. 4B View FIGURE 4 ) short and slender; femur widest at middle; tibia widened apicad, with apical process normal in size and short grasping comb; grasping comb approximately 0.15 times as long as tibia ( Fig. 4E View FIGURE 4 ); proportional lengths of femur, tibia, and tarsus 2.0: 1.7: 1.0. Middle and hind legs long ( Fig. 4C, D View FIGURE 4 ); tarsomere II longer than tarsomere I; middle tibia straight, covered with long setae on dorsal and ventral sides; hind tibia straight, covered with long setae on dorsal side; proportional lengths of femur, tibia, tarsomere I, and tarsomere II of middle leg 3.8: 3.6: 1.0: 1.3, and of hind leg 4.3: 5.4: 1.0: 1.3. Abdomen widest at segments IV and V; dorsal laterotergites extend horizontally to obliquely upward; dorsal laterotergite VII covered with long setae along lateral (outer) margin; segment VIII ( Fig. 4F View FIGURE 4 ) covered with long setae along lateral margin; posterior margin roundly concave in middle. Proctiger ( Fig. 4G View FIGURE 4 ) elongate-oval, with slender lateral process on each side in middle. Right paramere ( Figs. 4I View FIGURE 4 , 6A View FIGURE 6 ) large, arcuate, evenly curved, sparsely covered with short to long setae in basal half, twisted dorsally in apical half in dorsal view, acute at apex, with apex directed upward and forward. Left paramere ( Fig. 4H View FIGURE 4 ) generally similar to but smaller and shorter than right paramere.

Apterous female ( Figs. 1B View FIGURE 1 , 2B View FIGURE 2 , 5B View FIGURE 5 ). Generally similar to apterous male. Fore tibiae lacking grasping comb; square markings of abdominal mediotergites II, III, V–VII and dorsal laterotergite VI grayish-blue; mediotergite VIII grayish-blue; dorsal laterotergites extend obliquely to vertically upward.

Macropterous male and female ( Fig. 1C, D View FIGURE 1 ). Generally similar to apterous males and females, respectively. Pronotum wider, with lateral and posterior margins broadly rounded; meso- and metanota completely concealed under pronotum; hemelytron dark brown, with long white patch basally and 3–4 white spots on apical half; long white patch more than 3 times as long as its maximum width.

Measurements. See Table 1 View TABLE 1 .

Subgeneric placement. This new species belongs to the subgenus Pacificovelia Andersen & Weir, 2003 of the genus Microvelia based on the following diagnostic characters of the subgenus: grasping comb present on fore tibia only, parameres large and slightly asymmetrical, and proctiger elongate-oval with lateral process on each side ( Andersen & Weir 2003). Pacificovelia consists of more than 10 species, mainly known from the Oceanian and Australian regions, and three of these species are distributed throughout Asia ( Andersen & Weir 2003). Although in Japan, two species, M. kyushuensis Esaki & Miyamoto, 1955 and M. morimotoi Miyamoto, 1964 , were identified prior to the present study ( Andersen & Weir 2003), our research resulted in the recognition of three species in total.

Differential diagnosis. This new species is the most similar in general appearance to M. kyushuensis , but can be distinguished by a combination of the following characters (features of M. kyushuensis in parentheses): larger and more slender body approximately 2.5 times as long as its maximum width (approximately 2 times); longer male grasping comb on fore tibia approximately 0.15 times as long as tibia ( Fig. 4E View FIGURE 4 ) (less than 0.1 times); hemelytron of macropterous male and female basally with long white patch more than 3 times as long as its maximum width ( Fig. 1C, D View FIGURE 1 ) (approximately 2 times); a pair of square markings on abdominal mediotergites II, III, and V gray to grayish-blue ( Fig. 5A, B View FIGURE 5 ) (brownish-gray, Fig. 5C, D View FIGURE 5 ); and male right paramere evenly curved with twisted apical half ( Figs. 4I View FIGURE 4 , 6A View FIGURE 6 ) (right-angularly curved at basal third and not twisted in apical half, Fig. 6B View FIGURE 6 ). This new species is also similar in general appearance to M. morimotoi , the other member of Pacificovelia in Japan, but can be distinguished by a combination of the following characters (features of M. morimotoi in parentheses): larger body length 1.60–2.00 mm (1.08–1.35 mm); antennal segments II–IV equipped with long erect setae on outer (anterior) side (without long erect setae on outer (anterior) side); longer male grasping comb on fore tibia approximately 0.15 times as long as tibia ( Fig. 4E View FIGURE 4 ) (less than 0.1 times); and male right paramere twisted in apical half ( Figs. 4I View FIGURE 4 , 6A View FIGURE 6 ) (not twisted in apical half).

Distribution. Japan: The Yaeyama Islands of the Ryukyus (Ishigaki-jima Island, Iriomote-jima Island, and Yonaguni-jima Island) ( Fig. 8 View FIGURE 8 ).

Etymology. The specific name is named after the traditional Okinawan textiles “Minsa” mainly from the Yaeyama Islands, the type locality of the new species, referring to the checkered pattern on the dorsum of the abdomen; noun in apposition.

Ecological notes. Adults were collected from streams or river potholes ( Fig. 7 View FIGURE 7 ) along with the other veliid species Pseudovelia hirashimai Esaki, 1964 , and P. takarai Esaki, 1964 .

Remarks. This new species bears a striking resemblance to Microvelia kyushuensis . Our investigation has unveiled that the new species had been erroneously labeled as M. kyushuensis in no fewer than four publications ( Miyamoto 1964; Hayashi & Miyamoto 2005, 2006, 2018). Among these publications ( Hayashi & Miyamoto 2005, 2006, 2018), the veliid individuals depicted in the photographs were identified as M. kyushuensis , yet upon thorough examination, we have determined them all to be M. minsa sp. nov. The remaining publication ( Miyamoto 1964) documented M. kyushuensis from Ishigaki-jima Island, part of the Yaeyama Islands in the Ryukyus, for the first time, based on two female specimens, albeit lacking any illustrations or photographs facilitating species identification. Our scrutiny of the specimens utilized by Miyamoto (1964) uncovered that they were M. minsa sp. nov. ( Fig. 3 View FIGURE 3 ), although, regrettably, one of the two specimens sustained severe damage, rendering its identification difficult; the body shape and color of the markings on the abdomen barely made it possible to identify it.

For a span of at least 60 years, this new species has been mistakenly identified as M. kyushuensis . Hence, careful attention is imperative when interpreting findings from previous studies employing the scientific name M. kyushuensis .