Xylocopa caerulea, Wood, T. J., Risch, S., Orr, M. C. & Hogan, J. E., 2025

14a. Xylocopa insularis Smith, 1857 View in CoL

Fig. 13

Bombus coeruleus Fabricius, 1804: 345 , sex not stated [ Indonesia: Java; RMNH, neotype by present designation].

Xylocopa insularis Smith, 1857: 48 View in CoL , ♂ [ Malaysia: Borneo; OUMNH, lectotype by present designation] syn. nov.

Xylocopa bangkaënsis Friese, 1903: 206 View in CoL , ♀ ♂ [ Indonesia: Bangka; NHMW, lectotype by present designation] syn. nov.

Type material examined

Neotype

INDONESIA • ♀; W Java, Udjungkulon [ Ujung Kulon N.P.], Tjilamar ; 1–31 Dec. 1958; A.M.R. Wegner leg.; T.J. Wood det.; RMNH, RMNH.INS.1715657 ( neotype of Bombus coeruleus , by present designation).

Lectotype

INDONESIA • ♀; Asia Arch., Bangka; 1901; H. Kühn leg.; NHMW ( lectotype of Xylocopa bangkaensis , by present designation).

Lectotype

MALAYSIA • ♂; Sar. [ Sarawak]; [ 29 Oct. 1854 – 10 Feb. 1856]; OUMNH, ENT-HYME2775-01 ( lectotype indicated by Lieftinck in 1958, de facto lectotype of Xylocopa insularis , by present designation).

Other material examined

CHINA • 1 ♀; S China, Hainan, Jianfenling N. Nature Res.; 980–1050 m a.s.l.; 13–14 Jul. 2013; C.v. Achterberg leg.; T.J. Wood det.; RMNH, RMNH.INS.1715652 .

INDONESIA • 6 ♀♀; W Java, Udjungkulon [Ujung Kulon N.P.], Tjilamar ; 1 Nov.–31 Dec. 1958; A.M.R. Wegner leg.; T.J. Wood det.; RMNH • 1 ♀; Sumatra, SE coast, Laut Tador ; 29 Jan. 1949; R. Straatman leg.; T.J. Wood det.; RMNH • 1 ♀; Banca [Bangka]; v.d. Bossche leg.; T.J. Wood det.; RMNH • 1 ♀; Bangka Isl. ; 14–19 Mar. 1955; J.v.d. Vecht leg.; T.J. Wood det.; RMNH, RMNH.INS.1715641 • 1 ♀; Bangka, Toboali ; 18 Jun. 1930; J.v.d. Vecht leg.; T.J. Wood det.; RMNH, RMNH.INS.1715642 • 2 ♀♀; Banka, PK Pinang [Pangkalpinang]; 31 Oct. 1929; J.v.d. Vecht leg.; T.J. Wood det.; RMNH, RMNH.INS.1715643, RMNH.INS.1715644 • 1 ♀; Borneo Exp., G. Kenepai [Gunung Kenepai]; 21–31 Dec. 1893; Dr J. Büttikofer leg.; T.J. Wood det.; RMNH, RMNH.INS.1715627 • 1 ♀; Eil. Bunguran, Natuna ; 1–31 May 1895; v. Yosfelt leg.; T.J. Wood det.; RMNH, RMNH.INS.1715645 • 1 ♀; Kalang [Sidikalang, Sumatra]; Hillebrand leg.; T.J. Wood det.; RMNH, RMNH.INS.1715622 • 3 ♂♂; W Java, Mt Panggerano [ Pangrango], Tjisaroea Z. [ Cisarua]; 1000 m a.s.l.; 3–4 Nov. 1941; M.A. Lieftinck leg.; M.A. Lieftinck det.; RMNH • 2 ♂♂; W Java, Buitenzorg [Bogor]; 250 m a.s.l.; 16 Apr. 1940; M.A. Lieftinck leg.; M.A. Lieftinck det.; RMNH, RMNH.INS.1715638, RMNH.INS.1715639 • 1 ♂; W Java, Buitenzorg, Bogor ; 250 m a.s.l.; 1–31 Jan. 1954; M.A. Lieftinck leg.; M.A. Lieftinck det.; RMNH, RMNH.INS.1715637 • 1 ♀; Sipirok [remaining text illegible; Sumatra]; 1200 m a.s.l.; 20 Apr. 1996; R. Desmier de Chenon leg.; T.J. Wood det.; RMNH, RMNH.INS.1715650 • 1 ♀; Sumatra, Sipirok, Tapanuli ; 19 Sep. 1992; Dr Diehl leg.; T.J. Wood det.; RMNH, RMNH.INS.1715651 • 1 ♀; E Borneo, Balikpapan, Mentawir River ; 50 m a.s.l.; 1–31 Oct. 1950; A.M.R. Wegner leg.; T.J. Wood det.; RMNH, RMNH.INS.1715658 .

UNCLEAR • 3 ♀♀; Borneo; 30 Apr. 1903; M.C. Piepers leg.; T.J. Wood det.; RMNH • 1 ♀; Borneo; Muller leg.; T.J. Wood det.; RMNH .

Type locality

Borneo ( Sarawak).

Notes

Baker (1993: 196) wrote the following:

“ Two ♂♂ standing as insularis in the UMO type collection are labelled:-

a) ‘SAR.’ [white disc], ‘ Xylocopa insularis Smith’ [blue paper, Smith], ‘Lectotype’ (printed, red), ‘X. Sg, Cyaneoderes insularis F. Sm , ♂ det. M.A. Lieftinck 1958 Lectotype’ and ‘ Cyaneoderes caerulea [sic] F. var. insularis Sm. Det. M.A. Lieftinck 1958 Lectotype!’.

b) ‘SAR.’ [white disc], ‘ Xylocopa insularis Smith’ [blue paper, Smith] and ‘ X. ( Cyaneoderes) caeruleiformis M.W, ♂ det. M. A, Lieftinck 1958 ’. [ Maa, 1939: 94, gives caeruleiformis as a synonym of coerulea .]

These ♂♂ may be regarded as syntypes of insularis and Lieftinck’s choice of lectotype may be confirmed [designation not published?: Hurd & Moure give no references for Lieftinck after 1957]. The lectotype is in fair condition, the distal segments of tarsi II and R tarsus III lost”.

We agree with Baker’s position that Lieftinck’s lectotype designation is unpublished, and so we formally publish it here. Baker also listed X. insularis as a junior synonym of X. caerulea ( Fabricius, 1804) , but did not discuss this action or mark it with a “syn. nov.”. Given the examination of the lectotype, it is necessary to discuss the status of X. insularis and its treatment in the literature. At the present time, X. insularis is treated as specifically distinct from Xylocopa caerulea , two taxa exist that differ consistently in size, and are treated as distinct in areas where they co-occur, such as Singapore ( Mawdsley 2016; Ascher et al. 2022).

Although X. caerulea was nominally described from New Caledonia, a territory far to the east of its known distributional range (ending in Borneo and Java, e.g., see comments to this effect as early as Cockerell 1909), the use of this name in its current form and species concept is well established (e.g., Maa 1939; Hurd 1959; Mawdsley 2016). The type is considered lost (e.g., Maa 1939) and there is no record of its location in the catalogue of Fabrician types ( Zimsen 1964: 415, entry 1076). It was not recovered during searches for Fabrician bee material from the Southeast Asian region (e.g., Lieftinck 1958), and no specimens are present in the Fabricius collection housed in Copenhagen based on modern searches (L. Vilhelmsen pers. com.). Given these circumstances, particularly the questionable geographic provenance of the specimen, there is zero benefit seen in overturning the current species concept at the present time.

Consequently, it is desirable to designate a neotype. In line with the conditions of article 75.3 ( ICZN 1999), this neotype is needed to decisively settle the status of this name, and to decisively confirm it as the oldest name within the subgenus Cyaneoderes Ashmead, 1899 , and senior to other names that have been described from the western part of the Malay Archipelago, thus preserving nomenclatural stability. The selected specimen ( Fig. 14) is from the island of Java (West Java, Ujung Kulon), which is not close to the nominal terra typica of New Caledonia, but as this location does not fall within the geographic range occupied by the species to which this name has been applied, the reported terra typica is considered irrelevant. The selected specimen is a female; no sex was specified in the original description. This neotype selection allows the name X. caerulea to continue to be applied in its current manner. The neotype is deposited in the RMNH collection (unique reference number: RMNH.INS.1715657).

More pressingly, the recent revision of subgenus Cyaneoderes ( Mawdsley 2016) has not resolved existing issues and has introduced new problems. Mawdsley considered five species to be valid within this subgenus, namely X. abbotti ( Cockerell, 1909) described from Terong in Malaysia, X. bangkaensis Friese, 1903 described from Bangka Belitung Island next to Sumatra, X. caerulea , X. insularis , and X. tumida Friese, 1903 which was also described from Bangka Belitung Island. Mawdsley gives morphological criteria which other than size are related entirely to the colour and extent of the pubescence or the pigmentation of the wings (the latter more reliable for some groups of Xylocopa ). He also states that males are only known for two of the five species ( X. caerulea and X. insularis ), but this is not the case for X. bangkaensis as Friese (1903: 206) described the species from three females and one male. Mawdsley (2016: 56) also refers to the holotype female of X. bangkaensis (without specifying the repository), but no holotype was indicated by Friese, and to our knowledge no lectotype has been designated. Moreover, Mawdsley repeats chresonomic lists (e.g., that of Maa 1939), without re-examining types; specifically he repeats the synonymy of:

1) X. caeruleiformis Meade-Waldo, 1914 described from Sarawak and synonymised with X. caerulea ( Maa 1939) , whereas an examination of the type (images now available from the NHMUK data portal) shows that due to the smaller body size, hyaline wings, and lateral fringes of T2–4 blue, under Mawdsley’s (2016: table 1) criteria this taxon would be conspecific with X. tumida ,

2) Xylocopa caeruleiformis var. fusca Meade-Waldo, 1916 described from Sarawak (images likewise available) and synoymised with X. caerulea by Maa (1939), but would meet X. abbotti under Mawdsley’s criteria, and

3) X. coerulea var. viridis Meade-Waldo, 1916 described from Sarawak (images likewise available) and synoymised with X. caerulea by Maa (1939), this taxon being preoccupied by X. viridis Smith, 1854 and replaced by X. meadewaldoi Hurd, 1959 ; this taxon meeting X. caerulea under Mawdsley’s criteria.

Given the names described from Sarawak ( X. insularis , X. caeruleiformis , X. caeruleiformis var. fusca , and X. meadewaldoi ), that under Mawdsley’s criteria would fit four species, it is beneficial to clarify how many taxa are actually present on the island of Borneo and surroundings in order to have a robust chresonomic framework for X. insularis .

Examination of Cyaneoderes material in the RMNH collection ( 55 specimens, partim), including careful examination of males, examination of the lectotype of X. insularis , examination of type photographs, and careful reading of the description and diagnoses of species reveals that the five taxa of Mawdsley are just three taxa. These are a large-bodied species ( 20–28 mm in length) which shows a flattened clypeus with no longitudinal raised and shining ridge ( Fig. 15A), a small-bodied species ( 15–19 mm in length) which shows a conspicuous raised, polished, and shining ridge on the clypeus ( Fig. 15C, E), and a small-bodied species ( 15–19 mm in length) with a thin but distinctly raised longitudinal ridge on the clypeus ( Fig. 15F). Whilst the name of the first taxon remains X. caerulea , the earliest available name for the smaller taxon with a raised and polished clypeal ridge is actually X. tumida .

Smith (1857: 48) described the male of X. insularis as measuring 11 lines in length, and with a line equalling 1/12 th of an inch, this equals 23 mm. We confirm that this measurement is accurate based on a modern measurement of the OUMNH lectotype specimen. At this size, it is impossible for the name X. insularis to be applied to one of the small-bodied species, as is the case in Mawdsley. It was also the case in the RMNH collection, where some small-bodied specimens were identified as X. insularis by P.D. Hurd (labels dated 1957). In contrast, Lieftinck identified small-bodied specimens as X. caeruleiformis , labels dated 1955, thus implying an avoidance of the concepts of Maa (1939). Importantly, the lectotype of X. insularis also shows a thick tuft of hair on the clypeus that obscures the underlying structure ( Fig. 13C); this is typical of X. caerulea which shows a thick hair tuft here ( Fig. 15B), in contrast to the male of X. tumida which has sparse hairs on the clypeus ( Fig. 15D), allowing the raised and shining longitudinal ridge to be seen; such a ridge is absent on male X. caerulea when the thick hair tuft is either naturally abraded or actively removed by entomologists. The overall colouration and tergal extent of the body pubescence has no utility at all in separating the two species, as variation from brown, grey, green-grey, brown-blue, blue-green, and bright blue is possible. Xylocopa insularis is therefore formally synonymised with X. caerulea syn. nov.

The combination of body size, presence or absence of a raised, polished, and shining longitudinal midline on the clypeus (both sexes), the presence or absence of a thick obscuring hair tuft on the clypeus (males), and the male genital capsule allow for consistent separation of X. caerulea and X. tumida . With these revised species concepts, it is beneficial to explicitly state why certain taxa belong to the small-bodied species with a raised shining clypeal midline.

Xylocopa tumida ; Friese (1903: 205) clearly states the small body size ( ♀ 16–17 mm) and the presence of a raised shining longitudinal midline on the clypeus: “ Clypeus dichter; dieser mit breiter, wulstig erhabener, glatter Mittelfläche ” [Clypeus denser; this with broad, bulging, raised smooth median surface]. A single specimen remains in the NHMW collection ( Fig. 16); since Friese described the species from two females, the remaining specimen is designated as the lectotype. The specimen is small bodied, as expected, and shows faded greyish pubescence on the head, mesosoma, and first tergal segment.

Xylocopa dormeyeri ; Enderlein (1909: 204–205) clearly states the small body size ( ♀ 15–18 mm; ♂ 18– 18 ½ mm) and the presence of a raised shining longitudinal midline on the clypeus: “ Clypeus mit breiter, medianer, kräftiger und poliert glatter Längswalst ” [Clypeus with broad, median, strong and polished smooth longitudinal ridge].

Xylocopa caeruleiformis ; Meade-Waldo (1914: 454) clearly states the smaller body size ( ♀ 17–18 mm); this small size along with the raised shining longitudinal midline on the clypeus is clearly visible on the type photographs on the NHMUK data portal.

Xylocopa caeruleiformis var. fusca ; Meade-Waldo (1916) does not provide a detailed description, but the small ♀ body length of 16 mm and the typical clypeus with raised shining longitudinal midline are clearly visible on the type photographs on the NHMUK data portal. It is simply a specimen showing entirely brown pubescence on the mesosoma. These synonymies are formalised below in Section 14b. The remaining taxa listed as synonymous with X. caerulea View in CoL by Mawdsley (2016) remain junior synonyms of that species.

In the case of Xylocopa abbotti, Cockerell (1909: 415) View in CoL clearly states the smaller body size ( ♀ smaller; anterior wing not over 16 mm long). Examination of the type photographs shows that there is a longitudinal carina present on the clypeus, but it is narrow and is not strongly polished. It is retained as a valid species with a more northernly distribution; see Section 14c.

Finally, van der Vecht (1953) considered X. bangkaensis to be a form of X. caerulea occurring on Bangka Belitung Island, placing the taxon in combination as X. caerulea bangkaensis . Reading of Friese’s description in combination with an examination of the single female specimen remaining in the NHMW collection ( Fig. 17) and examined material from Bangka Island (including the two females mentioned by van der Vecht 1953: 67 from Pangkalpinang on 31 October 1929) shows that X. bangkaensis is a large bodied species ( ♀ 23–24 mm; ♂ 26–27) that has the clypeus “ unbewehrt ” [unreinforced], in reference to the lack of a raised longitudinal midline. There are no structural differences between typical female X. caerulea and X. bangkaensis , and indeed specimens of X. caerulea with greyish or brownish pubescence can be found on the islands of Natuna and Borneo, respectively ( RMNH). We therefore agree with van der Vecht but go further and argue that X. bangkaensis is simply a colour form, and does not merit subspecific status since it shows no consistent geographic range limit; it is formally synonymised with X. caerulea syn. nov. Although described from three females and a male, only one female could be found in the NHMW collection. This specimen was labelled with a red label as “ Lectotypus Hurd ’64 [1964]”, but this designation was never published. We now formally publish this specimen as the lectotype.

Current status

Xylocopa ( Cyaneoderes) caerulea ( Fabricius, 1804) View in CoL syn. nov.

Distribution

China ( Yunnan, Guangxi, Hainan *, Guandong), Myanmar, Vietnam, Thailand, Cambodia, Malaysia (Peninsula, Borneo), Singapore, Indonesia ( Sumatra, Bangka Belitung, Natuna, Java) ( Mawdsley

2016 partim; Ascher et al. 2022; Ascher & Pickering 2024; present study). The listing from Sulawesi ( Ascher & Pickering 2024) requires further investigation, as it was not considered part of the fauna of this island by van der Vecht (1953).