Loxosceles rufescens (Dufour, 1820)

Barrion-Dupo, Aimee Lynn A., Lit, Jr., Ireneo L., Duran, Camille Faith D., Cammayo, Ma. Francia Kyla M., Alviola, Marnelli S., Mercado, Sheila Mae Q., Osio, Cecille Ann L., Eusebio, Orlando L., Lucanas, Cristian C. & Barrion, Alberto T., 2024, Integrative taxonomy reveals first record of Loxosceles rufescens (Dufour, 1820) (Araneae, Sicariidae) in the Philippines, Biodiversity Data Journal 12, pp. 117072-117072 : 117072

Loxosceles rufescens (Dufour, 1820)

Loxosceles rufescens Scytodes rufescens Dufour, 1820 - Dufour (1820): 203; For full synonymy, see World Spider Catalogue.

Materials

Type status: Other material. Occurrence : catalogNumber: ARA-00526, 527; 528-530 ; individualCount: 5; sex: 2 males, 3 females; lifeStage: adult; preparations: in EtOH; occurrenceID: 617D84B3-4CE3-58F4-980F-0AD6ABA92187; Location : country: Philippines; stateProvince: Batangas; municipality: Lobo ; locality: Brgy. Biga, Kamantigue Cave ; verbatimLocality: PHILIPPINES: Luzon , Batangas, Lobo , Biga : Kamantigue Cave ; Identification : identificationID: Loxosceles rufescens; identifiedBy: NICER P3; Event : eventDate: 11-09-2022; year: 2022; month: 09; day: 11; habitat: Kamantigue Cave ; Record Level : type: PhysicalObject; institutionID: UPLB MNH; institutionCode: UPLBMNH Type status: Other material. Occurrence : catalogNumber: ARA-00531, 532, 533, 534 ; individualCount: 4; sex: 1 male, 2 females, 1 juvenile; lifeStage: 3 adults, 1 juvenile; preparations: in EtOH; occurrenceID: 31CBAEC6-CBA0-5A85-B4C4-BC53671C4089; Location : country: Philippines; stateProvince: Batangas; municipality: Lobo ; locality: Brgy. Biga, Kamantigue Cave ; verbatimLocality: PHILIPPINES: Luzon , Batangas, Lobo , Biga : Kamantigue Cave ; Identification : identificationID: Loxosceles rufescens; identifiedBy: NICER P3; Event : eventDate: 19-11-2022; year: 2022; month: 11; day: 19; habitat: Kamantigue Cave ; Record Level: type: PhysicalObject; institutionID: UPLB MNH; institutionCode: UPLBMNH

Description

Male (Fig. 2 A). Total length 8.05 + 0.92. Carapace: length 4.30 + 0.14, width 3.40 + 0.57, height 1.75 + 0.21. Abdomen: length 3.75 + 1.06, width 2.18 + 0.46, height 2.08 + 0.18. Pedipalp length 3.75; femur 1.40 long; patella 0.45; tibia 1.00 long, 0.60 wide; cymbium 0.50 long, 0.40 wide; bulb 0.40 long. 0.45 wide and embolus 0.50 long.; palpal tibia length/width ratio 1.67. Embolus (1.19 + 0.01) as long as width of globular bulb (1.16 + 0.01).

Carapace pale orange-brown marked with dorsal dark orange-brown violin-shaped marking. Eyes six in three dyads in a recurved transverse row. Sternum pale yellowish to cream. Chelicerae, labium and maxillae reddish-brown. Legs orange-brown. Abdomen ground colour cream brown to greyish-brown, with short, grey setae. Leg formula 2-1-4-3 (Table 2 ). Male palp. Cymbium noticeably shorter than tibia length (0.40:1.00), slightly longer than palp bulb. Embolus possessing a thin cylindrical shaft towards apex (Figs. 2B-2D). Female. Habitus as in (Fig. 2 E) Total length 8.10 + 1.63. Carapace: length 3.38 + 0.62, width 2.83 + 0.42, height 1.86 + 0.15. Abdomen: length 4.73 + 1.17, width 2.85 + 0.66, height 3.05 + 0.90. Colouration and eye arrangement same as male. Leg formula as in male (Table 2 ). Spermatheca (Fig. 2 F) short and rounded distally, its anterior end rounded and directed towards each other (converging) and basal area relatively wide.

Distribution

Southern Europe, northern Africa to Afghanistan, Iran. Introduced to the USA, Mexico, Peru, Macronesia, South Africa, India, Yemen, China, Japan, Korea, Laos, Malaysia, Thailand, Australia, Hawaii and Philippines (new record).

Notes

This represents a new record of the family Sicariidae Keyserling, 1880 and species in the Philippines. It can be distinguished from other spider families in the Philippines by the six eyes arranged in three dyads in a recurved row, relatively flat carapace, rounded abdomen and tarsal claws two (compared to Scytodidae : humped carapace, tarsal claws 2-3; and 6-eyed Pholcidae : eyes arranged in two distinct triads, abdomen usually elongate and narrow, tarsal claws 2-3).The Philippine specimens exhibit the typical spermatheca and male palp features of the Loxosceles rufescens -species group ( Binford et al. 2008, Fukushima et al. 2017). Brignoli (1969) and Zamani et al. (2020) noted several variations on the epigyne of L. rufescens in Mediterranean, Iran, Afghanistan and Turkmenistan species, but refrained from describing them as distinct species without additional specimens.

The spermatheca of Philippine specimens are short and rounded distally with reduced or absent spermathecal bilobation, similar to those from the Balkan Peninsula ( Naumova and Deltshev 2021), Mexico ( Valdez-Mondragón et al. 2018) and from Hormozgan in Iran ( Zamani et al. 2020), but slightly differs in the size of the inner receptacle lobe. It also closely resembles the Australian specimen recovered in the Iberian Clade by Duncan et al. (2010).

Similarly, the male palp of Philippine specimens conforms with the report of Lotz (2017) of L. rufescens : (a) the short cymbium; (b) cymbium slightly longer than palp bulb; (c) ratio of palp tibia length/height is 1.67; (d) palp cymbium noticeably shorter than the tibia [0.40:1.00]; and (d) embolus possessing a thin cylindrical shaft towards the apex (Fig. 2 B-D).

Overall, the examined morphological characters of the Philippine species conform with the present description of L. rufescens as presented in Lotz (2017), Valdez-Mondragón et al. (2018), Zamani et al. (2020), and Naumova and Deltshev (2021).

Furthermore, the results of the molecular analysis corroborate those obtained using classical morphological techniques. The BLASTn results of the COI sequences generated from four Philippine spider specimens (412-433 bp long) reveals significantly high similarity (percent identity = 98-100%) with those of L. rufescens . Meanwhile, the pairwise distance between the Philippine samples and those from Mediterranean samples ranges from zero to nearly 0.1 (Table 3 ). Although the taxonomy of L. rufescens is not yet fully resolved ( Duncan et al. 2010), the Philippine specimens closely match those presently considered as L. rufescens .

Interestingly, distances between Philippine specimens and those from India (Maharashtra), Portugal (Porto Santo) and Spain (Sagunt) were recovered to be zero. Historically around the 18th century, there is an existing trade route between India - Philippines ( Seshan 2006, Eang 2011), countries which were occupied by Portugal and Spain, respectively. Given this, it is possible that the Philippine populations have been introduced via this trade route. This hypothesis can be tested if other specimens of L. rufescens could be observed in areas following this trade route; unfortunately, molecular information from specimens in Perak, Malaysia is lacking. However, the distance between the eyes of females from Philippines resemble those from Malaysia (eye dyads separated by ~ 2-2.5 median eye diameter), but with slightly more recurved eyes ( Duncan et al. 2010).

Additionaly, distances between Philippine specimens and those from Australia (Adelaide) and USA (New York) were also recovered to be zero. Duncan et al. (2010) recovered both specimens to belong to the Iberian clade of L. rufescens . However, this may suggest an alternative route of introduction for the Philippine population.

On the other hand, Philippine specimens were recovered to be distant from those from Guangxi, China suggesting that they may have followed different routes of introduction. Luo and Li (2015) suggested that L. rufescens was introduced to China around 42,710-46,008 years ago which coincides with the movement of modern humans to East and South-East Asia.

Phylogenetic analysis shows three major clusters consisting of L. rufescens specimens (100% bootstrap support), Canarian species (74% bootstrap) and L. persica (57% bootstrap) (Fig. 3 ). In the L. rufescens cluster, the specimens from Kamantigue Cave, Lobo, Batangas (PH1-PH4) are grouped together with specimens from Australia (AU), Gran Canaria (GC), India (ID), Portugal (PT), Spain (SS) and America (US). This group is sister to a clade of L. rufescens specimens from China (GH), Turkey (KT), Italy (SI) and Spain (CS, VS).

Figures

Figure 2. Loxosceles rufescens (Dufour, 1820), male (A-D) and female (E-F); Habitus, dorsal view (A, E); palp: prolateral (B), retrolateral (C), apical (D); spermatheca (F). Abbreviations: f - femur, p - patella, Ti - tibia, c - cymbium, b - bulb, e - embolus.

Figure 3. UPGMA tree generated using the COI sequences of the four Philippine Loxosceles rufescens (Dufour, 1892) specimens and 20 other Loxosceles species. Evolutionary distances were calculated using the Tamura-Nei parameter model with 1,000 bootstrap iterations. AU - Adelaide, Australia; CH - Guangxi, China; CS - Cabo de Gata, Spain; FI - Fars, Iran; GC - Subida San Felipe, Gran Canaria; ID - Maharashra, India; KT - Kepez, Turkey; PH - Batangas, Philippines; PT - Porto Santo, Portugal; SI - Sardinia, Italy; SS - Sagunt, Spain; US - New York, USA; VS - Vilamarxant, Spain; YI - Yazd, Iran.